Search

In terms of field application, the archeospores released from Pyropia yezoensis blades are of great significance for increasing the number of seedlings on the cultivation nets, prolonging the harvest period, and improving yield and quality. To select a new strain of P. yezoensis with fast growth, good quality, high-temperature resistance, and a suitable quantity of archeospores released, an intraspecific hybridization was carried out between the improved strain (A-18) with almost no archeospores released and Py-26W' strain with a large quantity of archeospores released. A new strain S-15 was then isolated from the offspring. From 15 days of age, the total number of archeospores released from S-15 per blade for 21 consecutive days was 1353, while that from A-18 was only 6 (P < 0.05). After being cultured for 60 days, the mean length of the S-15 blades was 156.8 cm, which is 1.2 times longer than that of the A-18 blades. When blades aged 30 days (cultured at 18 ℃) were further cultured at 25 ℃ for another 30 days, both A-18 and S-15 showed a slow increase in blade length, but the Fv/Fm value of A-18 blades decreased by 13.0% (P < 0.01), while that of S-15 remained steady. After being cultured at 18 ℃ for 45 days, the contents of chlorophyll a and total phycobiliprotein were 9.8 and 68.1 mg/g in S-15, which were 23.3% (P < 0.05) and 17.3% (P > 0.05) higher than those of A-18, respectively. In summary, S-15 was characterized by fast growth, high phycobiliprotein content, high-temperature resistance, and a suitable quantity of archeospores released, which is expected to be applied in production and cultivation. [ABSTRACT FROM AUTHOR]

Background/Objectives: The classification and phylogenetic relationships of Gossypium hirsutum L. landraces, despite their proximity to southern Mexico, remain unresolved. This study aimed to clarify these relationships using SSR markers and hybridization methods, focusing on subspecies and race differentiation within G. hirsutum L. Methods: Seventy polymorphic SSR markers (out of 177 tested) were used to analyze 141 alleles and calculate genetic distances among accessions. Phylogenetic relationships were determined using MEGA software (version 11.0.13) and visualized in a phylogenetic tree. ANOVA in NCSS 12 was used for statistical analysis. Over 1000 inter-race crosses were conducted to assess boll-setting rates. Results: Distinct phylogenetic patterns were identified between G. hirsutum subspecies and races, correlating with boll-setting rates. Latifolium, richmondii, and morilli showed no significant increase in boll-setting rates in reciprocal crosses. Cultivars Omad and Bakht, as paternal parents, yielded higher boll-setting rates. Religiosum and yucatanense displayed high boll- and seed-setting rates as maternal parents but low rates as paternal parents. Additionally, phylogenetic analysis revealed a close relationship between cultivars 'Omad' and 'Bakht' with G. hirsutum race richmondii, indicating their close evolutionary relationship. Conclusions: Reciprocal differentiation characteristics of G. hirsutum subspecies and races, particularly religiosum and yucatanense, should be considered during hybridization for genetic and breeding studies. Understanding the phylogenetic relationships among G. hirsutum taxa is crucial for exploring the genetic diversity of this economically important species. [ABSTRACT FROM AUTHOR]

To select a new strain of Neoporphyra haitanensis with thin blades and high-temperature resistance, an intraspecific hybridization of a cultivated strain (WT-bo, ♂) and improved strain (HR-5, ♀) in N. haitanensis was carried out, and then a new strain qF-15 was isolated from the offspring based on heat stress and characteristics analysis. After being cultured for 40 days, the mean thickness of the blades was 22.3 μm in qF-15, which was 9.7% and 8.3% lower than that of WT-bo and HR-5, respectively; the total phycobiliprotein content was 122.9 mg/g in qF-15, which was 41.6% and 5.9% higher than that of WT-bo and HR-5, respectively. After being cultured for 45 days, the mean length of the blades was 70.4 cm in qF-15, which was 2.6- and 1.6-fold of that of WT-bo and HR-5, respectively. After being cultured for 7 days at 30 °C, the survival rate of conchospore germlings was 25.9% in qF-15, which was 439.6% and 223.8% higher than that of WT-bo and HR-5, respectively. The blades were cultured for 25 days at 23 °C and then cultured for another 20 days at 30 °C. Plenty of cells died in the blades of WT-bo, while only a little of cells died in the blades of HR-5 and qF-15. After the conchocelis-inoculated shells experienced the process of high temperature and shrunk of light, the time for the emergence of a lot of conchosporangial branch was about 20 days for the three strains. In summary, qF-15 was characterized by thin blades, high-temperature resistance of conchospore germlings and blades, fast growth, high phycobiliprotein content, and fast differentiation rate of conchocelis-inoculated shell, and it is expected to be applied in production and cultivation. [ABSTRACT FROM AUTHOR]

Intraspecific hybridization between distinct populations could increase the fitness and adaptive potential of biological control agents that often have low genetic diversity and can be inbred due to long‐term laboratory rearing often at small population sizes. Hybridization can also alter host preference and performance when the parental insect populations are adapted to different host plants. We investigated the effects of hybridization between two populations (Northern and Southern) of the psyllid, Aphalara itadori, that have different fitness on three invasive knotweed species (Japanese, giant, and Bohemian). Fecundity, host choice, and developmental success of second‐generation reciprocal hybrids and the parental psyllid populations were compared on the three knotweed species in multiple‐choice tests. Hybridization did not increase fecundity. All three knotweed species were accepted for oviposition without preference by the Southern and the two hybrid psyllid populations. The northern psyllid population laid the most eggs on Bohemian knotweeds but those were maladaptive choices since almost all eggs failed to develop. The developmental success of the parental psyllid populations was highest on the knotweed species they were originally collected from, on Japanese knotweed of the Southern psyllids and giant knotweed of the Northern psyllids. Hybrids had intermediate or higher survival on given knotweed hosts compared to their parents. These results can inform release tactics of A. itadori in different regions especially where there appear to be climatic and/or host mismatches such as in Michigan. In southern Michigan, based on climate the Northern psyllid population should be released. However, the most common knotweed species in the region are Bohemian and Japanese knotweeds that do not support the development of the Northern psyllids. In this case, hybrids that may carry cold adaptations of the Northern psyllids but have better developmental success on the prevailing knotweed species may be considered for release to increase establishment success. [ABSTRACT FROM AUTHOR]

Translocating individuals from multiple source populations is one way to bolster genetic variation and avoid inbreeding in newly established populations. However, mixing isolated populations, especially from islands, can potentially lead to outbreeding depression and/or assortative mating, which may limit interbreeding between source populations. Here, we investigated genetic consequences of mixing individuals from two island populations of the dibbler ( Parantechinus apicalis ) in an island translocation. Despite a high level of genetic divergence between the source populations ( F ST ranges 0.33-0.64), and significant differences in body size, individuals with different ancestries were able to successfully interbreed in captivity and in the wild. However, the genetic contributions from each source population were unequal initially despite each of the source populations contributing an equal number of founders. Mating success of captive animals based on the pedigree suggests that this bias toward one source population was due to founder mortality and the mating success of younger and heavier animals. Nevertheless, genetic contributions in the translocated population became equal over time with no parental purebreds, suggesting an extreme excess of hybrids across multiple years. While genetic variation in the translocated population was comparable or higher than the source populations, the increase was short-lived. Genetic composition of captive animals may not reflect what happens in the wild. These changes post-translocation highlight the need for continued genetic monitoring., Competing Interests: The authors declare no conflicts of interest., (© 2025 The Author(s). Evolutionary Applications published by John Wiley & Sons Ltd.)

• Rhododendron is an economic plant with decorative, spice, and medicinal value. • Ultrastructural observation and transcriptome analysis were conducted. • The hybrid incompatibility (HI) between R. 'XXL' × R. delavayi could attribute to post-fertilization isolation. • The plant hormone signal transduction and flavonoid biosynthesis play key role in HI. • MAPK signaling and plant-pathogen interaction pathways were involved in HI. Hybridization across species has been widely utilized to improve agriculturally important traits in Rhododendron. These interspecific hybridizations are often inhibited by reproductive barriers at the prezygotic and postzygotic stages. Thus, in order to character the barriers and reveal the underlying regulation mechanism of interspecific hybrid incompatibility in Rhododendron , we compared the pollen germination and pollen tube growth, fruit growth, seed number and germination rate between intraspecific (Rhododendron 'XXL' × R. 'XXL') and interspecific (R. 'XXL' × R. delavayi) hybridizations. After pollination, the pollen germination rate and pollen tube growth rate of interspecific hybridization (Inter) were always higher than that of intraspecific hybridization (Intra) during the whole observation period. Conversely, the fruits and ovules of Intra grew faster than that of Inter after 20 DAP. The ratio of shrunken embryos of Inter was 73.27 ± 10.19 %, which was significantly higher than that of Intra with 28.41 ± 8.33 % at 40 DAP. Moreover, the fruit setting rate, the average number of seeds per fruit and seed germination rate of Intra were significantly higher than that of Inter at 150 DAP. These results indicated that the barriers of interspecific incompatibility between R. 'XXL' × R. delavayi could be mainly ascribed to post-fertilization isolation. Consequently, RNA-Seq analysis on ovaries at three developmental stages from two hybridizations indicated that plant hormone signal transduction, flavonoid biosynthesis, MAPK signaling pathway and plant-pathogen interaction pathways might play important roles in regulation of hybrid incompatibility between R. 'XXL' × R. delavayi. The results can provide a basis for the study of the hybrid incompatibility mechanism of Rhododendron , and provide useful information for the breeding and conservation of genetic resources of Rhododendron. [ABSTRACT FROM AUTHOR]

The correlations were explored between fertility indicators of intraspecific V. vinifera hybrids and different cultivars were subjected to selfing or used in reciprocal crosses by testing them as female parents or male parents. Two cold-resistant and four high-quality cultivars were selected, and the offspring of fourteen crosses and six self-combinations were evaluated. The pollen viability of the six cultivars was determined by TTC staining. Compatibility and the rates of fruit-setting, seediness, germination, emergence, and seedling were measured as parameters that can affect fertility of both hybridization and self-crossing processes. Using principal component analysis, the six fertility indexes were transformed into comprehensive principal components, and the weights of the indexes were determined. Combined with the membership function method, the fertility index was comprehensively evaluated for different crosses to screen for hybrid combinations with higher fertility. The results showed a high positive correlation between the pollen viability of the cultivar subjected to selfing and the fruitsetting rate, seediness rate, and hybrid compatibility index of the cultivar used as the male parent for crossing. Additionally, there was a one-toone positive correlation between the fruit-setting rate, germination rate, emergence rate, and seedling rate of the selfed cultivar and the fruitsetting rate, germination rate, and seedling rate of the cultivar used as the female parent for crossing. There was some variation in the comprehensive fertility index values for the parents and combinations in different years. The comprehensive fertility index was always the highest for Ecolly as the male parent. The composite fertility index values were relatively high when Dunkelfelder, Cabernet Sauvignon, or Marselan were used as the female parent. The combinations of C1 (Cabernet Sauvignon x Ecolly), C3 (Marselan x Ecolly) and C6 (Dunkelfelder x Ecolly) exhibited relatively high comprehensive fertility indices, and pedigree clustering shows that these three combinations cluster into one class of highly fertile hybrid combinations. This study provides the basis for effective intraspecific hybrid breeding of grape (V. vinifera). [ABSTRACT FROM AUTHOR]

Downy mildew is a major disease that severely restricts the healthy and sustainable development of the global grape and wine industry, so there is significant interest in breeding high-quality disease-resistant varieties. In this study, hybridization was carried out between two disease-resistant and four high-quality varieties for eight hybrid combinations. The downy mildew resistance of 6 hybrid parents and 350 hybrid F1 progeny was determined by the leaf disc inoculation test, and the frequency distribution of the disease resistance grades was analyzed for the different populations. Agarose gel electrophoresis and disease resistance identification were used to screen SSR molecular markers of the tested hybrids for resistance to downy mildew. The results showed that minor disease-resistance genes in V. vinifera varieties were the main determinant of the variation in disease susceptibility among different varieties. V. vinifera resistance to downy mildew is inherited by a quantitative trait controlled by multiple genes. Intraspecific hybridization of V. vinifera can be applied to breed suitable intermediate materials or new types of disease resistance. The screening and verification of simple-sequence repeats (SSR) as molecular markers revealed that UDV-304, UDV-305, and UDV-737 could be used as standard markers for the identification of downy mildew resistance of hybrid progeny of Ecolly and Cabernet Sauvignon, UDV-305 could be used for the hybrid progeny of Meili and Cabernet Sauvignon, and VMC8g9 could be used for the hybrid progeny of Ecolly or Meili and Dunkelfelder. The disease-resistant progeny selected in this study can be used as intermediate materials for the breeding of new high-quality, disease-resistant varieties by intraspecific recurrent selection in V. vinifera. The screened standard markers can be utilized for rapid batch identification of hybrid progeny of different hybrid combinations to facilitate molecular marker-assisted breeding. [ABSTRACT FROM AUTHOR]

Populus nigra is an important autochthonous woody plant that can be grown as a renewable energy source. The possibility of its improvement through intraspecific hybridization was tested. Differences in biomass production, growth parameters, Melampsora larici-populina rust resistance and drought tolerance were evaluated among 19 intraspecific hybrids from controlled crosses, 2 clones selected from natural populations and the “MAX 4” clone (P. nigra × P. maximowiczii). These P. nigra clones from controlled crosses were chosen from more than 2000 hybrid individuals whose parents were selected from natural populations in the Czech Republic. A field trial was set up in Pruhonice, Czech Republic (320 m a.s.l., 591 mm rainfall annually, mean annual temperature of 9.5 °C). The planting density was 6061 plants ha-1, and the plants were coppiced three times at 3-year intervals. The trial was irrigated only during its establishment. Among the clones, significant differences were found in all the evaluated traits over three rotations. An average dry matter yield of the best clone “MAX 4” was 12.8 t ha-1 yr-1 over three harvests. The best black poplar clone reached up to 9.4 t ha-1 yr-1 in three harvests. Rust resistance was constant over 9 years and high for the three P. nigra clones (two from controlled crosses and one from natural populations). Moreover, the best P. nigra clones from controlled crosses showed higher drought tolerance than the “MAX 4” clone. Breeding progress was confirmed, and most of the P. nigra clones from controlled crosses performed better than the clones selected from natural populations. The trial validated the suitability of natural populations for use as gene sources for intraspecific hybridization and as sources of clones with traits comparable with those of interspecific clones. These new P. nigra clones can replace allochthonous clones in areas where autochthonous P. nigra populations are threatened by introgression.

In Southern Brazil, much of the livestock activity is developed in native grasslands. Studies about forage traits, frost tolerance and nutritional value of native forage species there has been increasing with better results of productive efficiency (animal gain). The objective of this work was to evaluate forage yield of forty-five intraspecific hybrids of segregating progenies of bahiagrass (Paspalum notatum Flügge) from agronomic analyses under greenhouse conditions and determine the reproduction mode of selected hybrids. The hybrids had great variability in all agronomic characteristics measured. The plants with the highest total dry mass production were 17PN10P3 and 17PN29P1 (sexual reproduction), 17PN10P5, 17PN16P3 and 17PN28P4 (apomictic reproduction). The high correlation of the total dry mass with tillers number and with the root dry mass demonstrate that the hybrids can be used as forage and also to reduce the effects of soil erosion in degraded areas. The evaluations of agronomic characteristics and the determination of the mode of reproduction of the selected hybrids allowed the identification of promising genetic materials for forage yield and to soil cover, selecting them for additional stages in the breeding program.

In the process of carrying out studies as a result of hybridization of soft wheat with spelt wheat, a number of new forms that differ in morphobiological and economically valuable features were obtained. The aim of the research was to expand the genetic diversity of soft wheat by hybridization with spelt wheat, analysis of the heterotic effect in hybrids in order to systematize the samples and obtain valuable original forms for the breeding process of creating high-yielding varieties. As a result of research the breeding technology of creating high-yielding forms of soft winter wheat by cross-species hybridization of Triticum aestivum L. × Triticum spelta L. has been improved. It has been determined that the plant height and ear length in hybrids are inherited by type of intermediate inheritance or negative dominance, the number of grains in the ear - by type of intermediate inheritance or positive dominance; ear grain weight - by type of superdominance or positive dominance. In F2 hybrids there is a dihybrid cleavage into forms with speltoid, squarehead and typical ear with a quantitative predominance of speltoid plants, which indicates the control of the 'ear shape' indication by two non-allelic genes. The ear shape of the soft wheat original varieties in relation to speltoid varieties turned out to be a recessive trait, but at the same time it was dominant to a squarehead form. Regardless of the genotypes of soft wheat included in the combination of crossbreeding with spelt wheat, red color ear indication was determined by a monogenic type of inheritance. Varieties of soft winter wheat Artaplot, Umanska Tsarivna and Freya have been created, which are included in the State Registry of Plant Varieties Suitable for Distribution in Ukraine and recommended for cultivation in Polissia. [ABSTRACT FROM AUTHOR]

Introduction. Rapeseed is a facultative autogamous plant; its percentage of cross-pollination is 10–50%, so rapeseed breeding engages the line and population breeding methods as well as the development of hybrids and all innovative research approaches.Material and methods. Among the main techniques used for the development of parent material and, eventually, cultivars at the Pustovoit Institute (VNIIMK) is the pedigree method (individual selection from intraspecific and interspecific hybrid populations, combined with inbreeding). Physical and chemical mutagenesis is also employed in rapeseed breeding at VNIIMK. The material with yellow-colored seed coat has been obtained by exposing rapeseed seeds to various doses of gamma rays (50, 100 and 150 kR). Seed treatment with chemical mutagens is primarily aimed at changing the fatty acid composition of oil.Results. Breeding achievements for winter and spring rapeseed, registered by VNIIMK in the State Register of Breeding Achievements of the Russian Federation over the past 15 years, are highly productive line cultivars with a seed yield of 4–5 t/ha for winter rapeseed, and 2–3 t/ha for spring rapeseed. Promising experimental interline hybrids, significantly exceeding the reference in seed yield (by 1.61–2.26 t/ha), have been developed. Yellowseeded lines, which exceed the black-seeded reference cv. ‘Tavrion’ in seed yield by 0.08–0.15 t/ha, have been selected. We developed the material with an oleic acid level of 78.9–80.5%.

Abstract The success rate of weed biological control programs is difficult to evaluate and the factors affecting it remain poorly understood. One aspect which is still unclear is whether releases of multiple, genetically distinct populations of a biological control agent increase the likelihood of success, either by independent colonization of different environmental niches or by hybridization that may increase the agent's fitness and adaptive ability. Since hybridization is often invoked to explain the success of unintentionally introduced exotic species, hybridization among biocontrol agents may be similarly important in shaping the effectiveness of biological control programs. In this study, we first evaluated intraspecific hybridization among populations of a weed biological control agent, the ragwort flea beetle, Longitarsus jacobaeae. These insects were introduced as part of a classical biological control program from Italy and Switzerland. We genotyped 204 individuals from 15 field sites collected in northwest Montana, and an additional 52 individuals that served as references for Italian and Swiss populations. Bayesian analysis of population structure assigned seven populations as pure Swiss and one population as pure Italian, while intraspecific hybrid individuals were detected in seven populations at frequencies of 5%–69%. Subsequently, we conducted a 2‐year exclusion experiment using six sites with Swiss beetles and three with hybrid beetles to evaluate the impact of biological control. We found that biological control by Swiss beetles and by hybrid beetles is effective, increasing mortality of the target plant, Jacobaea vulgaris, by 42% and 45%, and reducing fecundity of surviving plants by 44% and 72%, respectively. Beetle densities were higher and mortality of larger plants was higher at sites with hybrids present. These results suggest that hybridization of ragwort flea beetles at high‐elevation sites may improve biological control of tansy ragwort and that intraspecific hybridization of agents could benefit biological control programs.

Understanding hybridization barriers is relevant for germplasm conservation and utilization. The prezygotic barriers to hybridization include floral morphological differences like pistil and stamen length, pollen characteristics and pollen-pistil interactions. This study sought to elucidate the reproductive biology of Solanum aethiopicum; its mating systems and compatibility barriers. Eight genotypes of Solanum aethiopicum were examined for differences in floral morphology, phenology and cross compatibility in a full diallel mating design, with assessment of fruit set, seed set and seed viability. In-vivo pollen tube growth was observed for failed crosses at 24, 48 and 72 h after pollination. All genotypes had heterostyly flowers, with predominantly small white petals. Incompatibility was observed in five out of 39 combinations. All selfed genotypes displayed compatibility implying the genotypes are self-compatible. Pollen–pistil incompatibility, which was exhibited in four out of the five failed cross combinations, occurred on the stigma, upper style and lower style, a phenomenon typical in Solanaceae. Solanum aethiopicum is self-compatible and majorly self-pollinating but has features that support cross-pollination.

A southern population (S) from Xiushui County (29°1′N, 114°4′E) and a northern population (N) from Shenyang city (41°48′N, 123°23′E) of the cabbage beetle, Colaphellus bowringi vary greatly in their life-history traits, and may serve as an excellent model with which to study the inheritance of life-history traits. In the present study, we performed intraspecific hybridization using the two populations, comparing the key life-history traits (fecundity, development time, body weight, growth rate, and sexual size dimorphism (SDD)) between the two populations (S♀ × S♂ and N♀ × N♂) and their two hybrid populations (S♀ × N♂ and N♀ × S♂ populations) at 19, 22, 25, and 28°C. Our results showed that there were significant differences in life-history traits between the two parental populations, with the S population having a significantly higher fecundity, shorter larval development time, larger body weight, higher growth rate, and greater weight loss during metamorphosis than the N population at almost all temperatures. However, these life-history traits in the two hybrid populations were intermediate between those of their parents. The life-history traits in the S × N and N × S populations more closely resembled those of the maternal S population and N population, respectively, showing maternal effects. Weight loss for both sexes was highest in the S population, followed by the S × N, N × S, and N populations at all temperatures, suggesting that larger pupae lost more weight during metamorphosis. The changes in SSD with temperature were similar between the S and the S × N populations and between the N and the N × S populations, also suggesting a maternal effect. Overall, our results showed no drastic effect of hybridization on C. bowringi, being neither negative (hybrid inferiority) nor positive (heterosis). Rather, the phenotypes of hybrids were intermediate between the phenotypes of their parents. [ABSTRACT FROM AUTHOR]

Downy mildew is a major disease that severely restricts the healthy and sustainable development of the global grape and wine industry, so there is significant interest in breeding high-quality disease-resistant varieties. In this study, hybridization was carried out between two disease-resistant and four high-quality varieties for eight hybrid combinations. The downy mildew resistance of 6 hybrid parents and 350 hybrid F1 progeny was determined by the leaf disc inoculation test, and the frequency distribution of the disease resistance grades was analyzed for the different populations. Agarose gel electrophoresis and disease resistance identification were used to screen SSR molecular markers of the tested hybrids for resistance to downy mildew. The results showed that minor disease-resistance genes in V. vinifera varieties were the main determinant of the variation in disease susceptibility among different varieties. V. vinifera resistance to downy mildew is inherited by a quantitative trait controlled by multiple genes. Intraspecific hybridization of V. vinifera can be applied to breed suitable intermediate materials or new types of disease resistance. The screening and verification of simple-sequence repeats (SSR) as molecular markers revealed that UDV-304, UDV-305, and UDV-737 could be used as standard markers for the identification of downy mildew resistance of hybrid progeny of Ecolly and Cabernet Sauvignon, UDV-305 could be used for the hybrid progeny of Meili and Cabernet Sauvignon, and VMC8g9 could be used for the hybrid progeny of Ecolly or Meili and Dunkelfelder. The disease-resistant progeny selected in this study can be used as intermediate materials for the breeding of new high-quality, disease-resistant varieties by intraspecific recurrent selection in V. vinifera. The screened standard markers can be utilized for rapid batch identification of hybrid progeny of different hybrid combinations to facilitate molecular marker-assisted breeding.

ABSTRACT The two-spotted spider mite (Tetranychus urticae) is the main pest encountered in strawberry cultivation in protected environments, causing damage and increasing the cost of production associated with chemical control. Breeding programs are essential for obtaining new cultivars that are more tolerant to two-spotted spider mites. The objective was to evaluate whether the leaf trichomes mediatethe resistance of intraspecific strawberry hybrids to two-spotted spider mites. Preselected hybrids were subjected to infestation by two-spotted spider mites and evaluated via the no-choice assay and the travel test. Resistance was correlated with the density of trichomes, both glandular and non-glandular, present on the surface of the leaflets of strawberry genotypes. The results indicated that there is an influence of hybrids and cultivars on the behavior of the pest, allowing the verification of the existence of resistant genotypes (RVDA#16, RVCS#44 and Camino Real). These treatments resulted in low numbers of eggs deposited and hatched compared with the other treatments and shorter distances traveled by two-spotted spider mites on the surface of leaflets. It was also verified that the glandular trichomes presented a significant negative correlation with the average distance traveled by two-spotted spider mites on the surface of the leaf discs, indicating that these structures alter the behavior of these arthropods. Genotype resistance was associated with the presence of glandular trichomes. In addition to the superiority of the agronomic and postharvest attributes of the preselected hybrids (RVDA#16 and RVCS#44) identified in the previous selection efforts, they proved to be promising materials for achieving resistance to the spider mite, revealing important genotypes for use as cultivars and particularly as parents in breeding programs.

Key message: Creation of second generation Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) hybrids based on parents from geographically distant locations did not appreciably increase variance in height, frost damage and bud break. New and favorable trait combinations between height and the two adaptive traits were found in the F2 populations. Context: Increased genetic variance and new trait combinations can improve selection efficiency in terms of selection response and increased adaptability. Aims: This project tested a novel method for generating higher genetic variance and new trait combinations in Douglas-fir populations. Methods: Parents from Southern British Columbia (BC), Washington (WA), Oregon (OR), and Northern BC (NBC) were crossed within each provenance; then selections from BC were crossed with the other sources to create three F1 interpopulation generations. Unrelated random selections from the same F1 population were subsequently crossed to produce three F2 populations. The parental, F1 and F2 generations were concurrently grown in three field tests and were evaluated for height, frost damage, and bud break date. Results: Significant segregation variances were found only in the BCxNBC cross for height in two sites and frost damage in one site and in the BCxOR cross for bud break in one site. In the BCxNBC cross, correlations between breeding values for height and frost damage changed from 0.71 in F1 to − 0.04 in F2 and between height and bud break from − 0.71 to − 0.26. In the BC-OR cross, correlations between height and bud break changed from − 0.71 in F1 to − 0.49 in F2. Conclusion: Our results suggest that creation of wide-cross hybrids may not be very effective in increasing segregation variance in traditional tree improvement programs but in some cases may be considered to increase diversity of trait combinations. [ABSTRACT FROM AUTHOR]

The Asian corn borer, Ostrinia furnacalis, is a serious pest and is widely distributed in corn-producing regions throughout China. This insect enters facultative diapause as fully grown larvae in response to short day lengths. Here, we evaluate the changes in diapause incidence and critical day length (CDL) by crossing a tropical strain with five subtropical and temperate strains from a 2897-km latitudinal gradient to investigate the latitudinal variations in diapause induction and CDL and their heredity. Photoperiodic responses of diapause induction in the different geographical strains at different temperatures showed that diapause incidence and CDL increased with increasing latitude and decreased with increasing temperature. Similarly, diapause incidence and CDL for the hybrid strains also showed an increase with increasing latitude or decreasing temperature. Conversely, the diapause incidences were significantly lower and the CDLs were significantly shorter in hybrid strains than their parents with high diapause incidence. Furthermore, the males had significantly more influence than the females on the incidence of diapause in subsequent progeny. Diapause incidence and CDL in O. furnacalis are strikingly different among pure strains and hybrid strains. The photoperiodic response controlling diapause is strongly heritable, with diapause being a partial dominant character over nondiapause, with the incidence of diapause mainly determined by the male parent. These results can help us to predict the time course of diapause induction in nature and may provide a genetic means for pest management by providing information on the overwintering capabilities of the hybrids. [ABSTRACT FROM AUTHOR]

Cotton is an important agro-industrial crop across the globe. Improving the fiber quality and yield potential of cotton are major commercial targets for cotton breeders. The cotton lint yield is computed by multiplying three fundamental yield constituents: average boll weight, boll number per unit ground area, and lint percentage. The cotton species Gossypium arboreum exhibits a wide range of desirable traits, which are absent in the congener Gossypium hirsutum. Four parental lines of G. hirsutum and G. arboreum, with significant differences in boll-related traits, were used to develop the following four F2 populations: Mei Zhongmian × Chimu Heizi (MC), Mei Zhongmian × L-02292-3 (ML), Dixie king × Suyuan 04-44 (DS), and Dixie king × Pamuk (DP), in order to study complex traits, such as boll weight (BW) (g), lint percentage (LP) (%), boll upper width (BUW), boll medium width (BMW), boll lower width (BLU), and boll length (BL) (mm). In segregation populations, extensive phenotypic differences and transgressive segregation were observed. The results show that most of the correlation clusters were negatively associated with boll weight and lint percentage. The positive correlation clusters were observed among boll upper width (BUW), boll medium width (BMW), boll lower width (BLW), and boll length (BL). Seven of the twenty-four extracted principal components had eigenvalues > 1. This accounted for 62.2% of the difference between the four F2 populations. Principal component 1 accounted for 15.1% of the overall variability. The variation in principal component 1 was mainly attributed to boll lower width (BLW), boll medium width (BMW), boll upper width (BUW), boll length (BL), and boll weight (BW) of the ML population. The heritability estimates varied between high, medium, and low for various traits among the studied F2 populations. Interestingly, all traits demonstrated low genetic advance, which indicates that non-additive genes controlled these characters and that direct selection for these traits is not beneficial. The outcome of the present investigation will help to develop cotton cultivars with improved boll weight and lint percentage.

Purpose. Analysis of the process of hexaploid triticale breeding for winter hardiness by intraspecific hybridization method using systemic ecological tests under contrasting conditions. Methods. Dialectical investigation, field experiments, laboratory testing and statistical evaluation. Results. The results of breeding winter and alternate triticale varieties possessing a complex of valuable traits by the method of intraspecific hybridization of forms of different types of development using systemic ecological tests under contrasting conditions (Forest-Steppe – extremely arid Steppe) and at low temperatures were presented. During the years of research (1980–2005), 18 varieties were developed and transferred to the state testing, 17 of them were registered. Conclusions. Thus, the effective selection of highly productive genotypes with increased and high winter hardiness is possible from populations obtained by crossing hexaploid triticale of different types of development (winter triticale with spring and alternate ones) and contrasting level of frost and winter hardiness. During the period of 1980–2015, medium-tall and dwarf varieties of winter (‘Amfidyploid 256’, ‘Garne’, ‘Kharroza’, ‘Rarytet’, ‘Timofey’, etc.) and alternate (‘Nikanor’, ‘Yaroslava’, ‘Plastun Volynskyi’) triticales were developed. They are superior to the standard varieties of soft winter wheat for the critical temperature of freezing by -0.5...- 2.0 °C, characterized by increased (up to 9–12 t/ha) grain yield of various quality depending on the purpose of use.

This article is devoted to the creation of a new material of sunflower fertility reducing agents, having an optimal combination of tribenuron-methyl resistance and a sufficient vegetation period for the production of hybrids in zones with a short frost-free vegetation period. Lines used as a source of tribenuron-methyl resistance were purchased by Sativa LLC at the University of North Dakota Seed Fund (USA). The maximum resistance to aherbicide treatment was demonstrated by plants of hybrid combinations received by using the paternal line B0708VG, which line was significantly superior to the B0707VG line. Also, in the generation of the B0708VG line there is a tendency for increased productivity compared to the generation of the line B0707VG. The use of the method of intraspecific hybridization of the line - a carrier of the resistance gene SURES-2 followed by negative selection against the background of herbicide treatments makes it possible to create promising paternal forms with a sufficient period of vegetation and duration of the period «rise-start of flowering»for zones with a short frost-free period and having resistance to the tribenuron-methyl. [ABSTRACT FROM AUTHOR]

Genetic admixture, the intraspecific hybridization among divergent introduced sources, can immediately facilitate colonization via hybrid vigor and profoundly enhance invasion via contributing novel genetic variation to adaption. As hybrid vigor is short‐lived, provisioning adaptation is anticipated to be the dominant and long‐term profit of genetic admixture, but the evidence for this is rare. We employed the 30 years' geographic‐scale invasion of the salt marsh grass, Spartina alterniflora, as an evolutionary experiment and evaluated the consequences of genetic admixture by combining the reciprocal transplant experiment with quantitative and population genetic surveys. Consistent with the documentation, we found that the invasive populations in China had multiple origins from the southern Atlantic coast and the Gulf of Mexico in the US. Interbreeding among these multiple sources generated a "hybrid swarm" that spread throughout the coast of China. In the northern and mid‐latitude China, natural selection greatly enhanced fecundity, plant height and shoot regeneration compared to the native populations. Furthermore, genetic admixture appeared to have broken the negative correlation between plant height and shoot regeneration, which was genetically‐based in the native range, and have facilitated the evolution of super competitive genotypes in the invasive range. In contrast to the evolved northern and mid‐latitude populations, the southern invasive populations showed slight increase of plant height and shoot regeneration compared to the native populations, possibly reflecting the heterotic effect of the intraspecific hybridization. Therefore, our study suggests a critical role of genetic admixture in accelerating the geographic invasion via provisioning rapid adaptive evolution. [ABSTRACT FROM AUTHOR]

Iva is a new Bulgarian gladiolus variety created at the Institute of Ornamental and medicinal Plants - Sofia by the method of intraspecific hybridization, i.e. by crossing Oasis and Blues varieties. Variety Iva is of high ornamental quality with purple color, medium high, very strong and light green stem, that makes it competitive on the market. The new variety is characterized by earlier flowering period in comparison with standard cultivar Blues, respectively 13 days. The number of blossoms per one plant, yield of cut flower and corms, and weight of cormels /100 m2, from the new variety are higher in comparison with the standard variety Blues, respectively 16.30 %, 9.61% аnd 45.6%. The cut flowers of variety Iva show longer vase life in water, than the standard variety, respectively 4 days. The new variety is suitable for greenhouse and field production, urban landscaping purposes. [ABSTRACT FROM AUTHOR]

It is commonly observed that if the genetic divergences between parental lineages are too marked, the intermixed offspring might not be successful or might present reduced fitness, i.e., hybrid inferiority. In the present study, we performed an intraspecific hybridization using two populations of the Asian corn borer, Ostrinia furnacalis: a southern population (S) from Huizhou city (23.09°N, 114.4°E) and a northern population (N) from Harbin city (44.9°N, 127.2°E). The key life-history traits were compared between the two populations with geographical reproductive isolation and their two hybrid populations (S♀ × N♂ and N♀ × S♂ populations) at 20, 24, 28 and 32 °C. Our results showed that there were significant differences in life-history traits in the two parental populations, with the S population performing better. However, the two hybrid populations exhibited delayed larval development time, relatively reduced body weight, lower growth rate and sex ratio distortion compared with their parents. Our results provided further evidence that intraspecific hybridization between the two geographical populations reduced the fitness of the hybrids. The sexual size dimorphism was also different between the pure populations and the hybrid populations. We also found that the sex ratios in the two hybrid populations were mainly influenced by the genotype of the mothers. The negative effects of intraspecific hybridization on the key life-history traits may provide a genetic means of pest management to suppress pest populations. [ABSTRACT FROM AUTHOR]

The success rate of weed biological control programs is difficult to evaluate and the factors affecting it remain poorly understood. One aspect which is still unclear is whether releases of multiple, genetically distinct populations of a biological control agent increase the likelihood of success, either by independent colonization of different environmental niches or by hybridization that may increase the agent's fitness and adaptive ability. Since hybridization is often invoked to explain the success of unintentionally introduced exotic species, hybridization among biocontrol agents may be similarly important in shaping the effectiveness of biological control programs. In this study, we first evaluated intraspecific hybridization among populations of a weed biological control agent, the ragwort flea beetle, Longitarsus jacobaeae. These insects were introduced as part of a classical biological control program from Italy and Switzerland. We genotyped 204 individuals from 15 field sites collected in northwest Montana, and an additional 52 individuals that served as references for Italian and Swiss populations. Bayesian analysis of population structure assigned seven populations as pure Swiss and one population as pure Italian, while intraspecific hybrid individuals were detected in seven populations at frequencies of 5%–69%. Subsequently, we conducted a 2‐year exclusion experiment using six sites with Swiss beetles and three with hybrid beetles to evaluate the impact of biological control. We found that biological control by Swiss beetles and by hybrid beetles is effective, increasing mortality of the target plant, Jacobaea vulgaris, by 42% and 45%, and reducing fecundity of surviving plants by 44% and 72%, respectively. Beetle densities were higher and mortality of larger plants was higher at sites with hybrids present. These results suggest that hybridization of ragwort flea beetles at high‐elevation sites may improve biological control of tansy ragwort and that intraspecific hybridization of agents could benefit biological control programs. [ABSTRACT FROM AUTHOR]

Studies of the inheritance and and variability of chasmo- and cleistogamous types of cotton flower on the base of intraspecies hybridization of Gossypium barbadense L. are an urgent genetical task, whose applications involve plant breeding and seed industry. The purpose of our study was to determine the genetic control of this trait on the base of the regularity of alternative chasmo- and cleistogamous types of flowers in intraspecific hybrids of G. barbadense species. It is of theoretical and practical significance in the development of isogenic forms, lines, and varieties with the fully closed cleistogamous type of flowers, possessing important commercial traits. A pioneering method was elaborated for determining the genetic control of chasmo- and cleistogamous types of flowers in inrtaspecific hybridization of Gossypium barbadense L., which was a continuation of our studies on interspecific cotton hybridization. Two strategies were applied to the genetic analysis of hybrids: (1) paired reciprocal hybrids F1, F2 and (2) backcrossed hybrids Fb. On the grounds of these strategies, we determined the inheritance mode of flower types in reciprocal hybrids F1, which possessed the c1cg1Cg2cg2 genotype with chasmogamous flowers without reciprocal difference. The classes segregated in F2 as follows: 1 (cg1cg1Cg2Cg2) : 2 (cg1cg1Cg2cg2) : 1 (cg1cg1cg2cg2), where cleistogamy was double recessive (This trait shows the complete dominance inheritance pattern.) Segregation into two phenotypic classes occurs in the 3:1 ratio, i.e., three plants with chasmogamous flowers per one cleistogamous. The segregation Fb is 1:1; i.e., 1 chasmogamous : 1 cleistogamous. Thus, cotton chasmogamy is inherited in F2 according to the Mendelian law in a completely dominant manner: 3:1, which is proven by the Fb cross.

Premise of the Study: Hybridization between previously isolated species or lineages can stimulate invasiveness because of increased genetic diversity and inherited traits facilitating competitive and reproductive potential. We evaluated differences in stand characteristics and sexual and vegetative reproduction among native, introduced, and hybrid Phragmites australis lineages in the southwestern United States. We also assessed the degree of hybridization among lineages and backcrossing of hybrids with parental lineages. Methods: Growth and morphological characteristics were measured in native, introduced, and hybrid Phragmites stands to evaluate relative cover and dominance in associated plant communities. Panicles were collected from stands to evaluate germination, dormancy, and differences in seed traits. Seedlings from germination trials were genotyped to determine frequency of crossing and backcrossing among lineages. Key Results: Introduced and hybrid Phragmites stands had significantly greater stem and panicle densities than native stands and were more likely to be dominant members of their respective plant communities. Hybrid seed outputs were significantly greater, but hybrid seeds had lower germination rates than those from native and introduced lineages. We detected a novel hybridization event between native and introduced lineages, but found no strong evidence of hybrids backcrossing with parental lineages. Conclusions: Hybrid Phragmites in the Southwest exhibits reproductive, genetic, and morphological characteristics from both parental lineages that facilitate dispersal, establishment, and aggressive growth, including high reproductive output, rhizome viability, and aboveground biomass, with smaller seeds and greater genetic diversity than its progenitors. Our results show hybrids can inherit traits that confer invasiveness and provide insight for managing this species complex and other cryptic species with native and introduced variants with potential for intraspecific hybridization. [ABSTRACT FROM AUTHOR]

Hybridization is widely used. However, for a long time, systematic theories and technologies related to hybridization in fish have been lacking. In this study, through long-term systematic research, we investigated and obtained the main rules regarding inheritance and reproduction related to fish distant hybridization. Furthermore, we established one-step and multistep breeding technologies that were suitable for interspecific hybridization and intraspecific hybridization. Simultaneously, we used these two breeding technologies to produce a batch of diploid fish lineages and tetraploid fish lineages and improved fishes. In addition, we widely discuss the methods, technologies and results of hybridization breeding, referring to the domestic and foreign literature on fish hybridization. We hope that this paper will be beneficial for the research and application of fish hybrid breeding. [ABSTRACT FROM AUTHOR]

Hybridization can combine the genomes of different strains or species, which leads to changes of genotype and phenotype in the hybrids. In this study, we aimed to investigate the genetic variations of hybrids (WR-F1 and WR-F2) derived from the intraspecific hybridization of white crucian carp (Carassius auratus cuvieri, WCC, ♀) and red crucian carp (Carassius auratus red var., RCC, ♂). Here, we compared the orthologous genes in the liver transcriptomes of hybrids with those of WCC and RCC, and classified the orthologous genes into eight gene patterns within three categories (chimera, mutant, and biparental origin genes). The results revealed 19.04%, 4.17% chimeric genes and 6.90%, 5.05% mutations of orthologous genes in WR-F1 and WR-F2 respectively. Seventeen of twenty-three characterized genes (77%) were confirmed to be the chimeras at the genomic DNA level. The GO classification discovered that some chimeric and mutant genes were related to metabolic process, immune system and developmental process in WR-F1. Our results provide the new evidence that hybridization can combine the parental genomes, leading to changes in the genotype of the resultant hybrids. This is the first report on the formation of chimeric genes from fish intraspecific hybridization, which is potentially interesting from the context of both evolution and the genetic breeding of fish. [ABSTRACT FROM AUTHOR]

Successive rearing in laboratory conditions can result in the loss of genetic diversity, inbreeding depression and adaptation to the captive environment, affecting the quality of the insects reared and compromising their field performance. Introduction of genetic variation by admixing different populations may increase the fitness of populations, minimizing the negative effects of rearing many generations in artificial conditions. We experimentally investigated the role of intraspecific hybridization in enhancing the fitness of the egg parasitoid Trichogramma galloi Zucchi, 1988 (Hymenoptera: Trichogrammatidae), by reciprocally crossing three populations. Our results showed that the mating type did not affect the number of crosses that produced viable daughters. Homotypic crosses produced 94% viable daughters, while heterotypic crosses produced 92%. There were neither mating incompatibilities nor reproductive barriers between these populations. However, we observed a low fitness value for females from one of the populations studied. The fitness of hybrids was either unchanged or improved (in one case) when compared to the parental populations. We discuss the implications of our results and suggest future research directions. [ABSTRACT FROM AUTHOR]

Transposable elements (TE) and tandem repeats (TR) compose the largest fraction of the plant genome. The abundance and repatterning of repetitive DNA underlie intrapopulation polymorphisms and intraspecific diversification; however, the dynamics of repetitive elements in ontogenesis is not fully understood. Here, we addressed the genotype-specific and tissue-specific abundances and dynamics of the Ty1-copia, Ty3-gypsy, and LINE retrotransposons and species-specific Spelt1 tandem repeat in wild diploid goatgrass, Aegilops speltoides Tausch. Copy numbers of TEs and TR were estimated by real-time quantitative PCR in vegetative and generative tissues in original plants from contrasting allopatric populations and artificial intraspecific hybrids. The results showed that between leaves and somatic spike tissues as well as in progressive microsporogenesis of individual genotypes, the copy numbers of three TEs correlatively oscillated between 2- to 4-fold and the TR copy numbers fluctuated by 18- to 440-fold. Inter-individual and intraorganismal TEs and TR copy number dynamics demonstrate large-scale parallelism with extensive chromosomal rearrangements that were detected using fluorescent in situ hybridization in parental and hybrid genotypes. The data obtained indicate that tissue-specific differences in the abundance and pattern of repetitive sequences emerge during cell proliferation and differentiation in ontogenesis and reflect the reorganization of individual genomes in changing environments, especially in small peripheral population(s) under the influence of rapid climatic changes. [ABSTRACT FROM AUTHOR]

Hybridization creates unique allele combinations which can facilitate the evolution of invasiveness. Frequent interspecific hybridization between the Siberian elm, Ulmus pumila, and native elm species has been detected in the Midwestern United States, Italy and Spain. However, Ulmus pumila also occurs in the western United States and Argentina, regions where no native elm species capable of hybridizing with it occurs. We examined whether inter- or intraspecific hybridization could be detected in these regions. Nuclear markers and the program STRUCTURE helped detect interspecific hybridization and determine the population genetic structure in both the native and the two non-native ranges. Chloroplast markers identified sources of introduction into these two non-native ranges. No significant interspecific hybridization was detected between U. pumila and U. rubra in the western United States or between U. pumila and U. minor in Argentina and vice versa. However, the genetic findings supported the presence of intraspecific hybridization and high levels of genetic diversity in both non-native ranges. The evidence presented for intraspecific hybridization in the current study, combined with reports of interspecific hybridization from previous studies, identifies elm as a genus where both inter- and intraspecific hybridization may occur and help maintain high levels of genetic diversity potentially associated with invasiveness. [ABSTRACT FROM AUTHOR]

Biological invasions are often associated with multiple introductions and genetic admixture of previously isolated populations. In addition to enhanced evolutionary potential through increased genetic variation, admixed genotypes may benefit from heterosis, which could contribute to their increased performance and invasiveness. To deepen our understanding of the mechanisms and management strategies for biological invasions, we experimentally studied whether intraspecific admixture causes heterosis in common ragweed ( Ambrosia artemisiifolia) by comparing the performance of crosses (F1) between populations relative to crosses within these populations for each range (native, introduced) under different ecologically relevant conditions (control, drought, competition, simulated herbivory). Performance of admixed genotypes was highly variable, ranging from strong heterotic effects to weak outbreeding depression. Moreover, heterosis was not uniformly observed among between-population crosses, but certain native population crosses showed considerable heterosis, especially under simulated herbivory. In contrast, heterosis was largely absent in crosses from the introduced range, possibly implying that these populations were already admixed and benefit little from further mixing. In conclusion, these results support the hypothesis that heterosis may contribute to biological invasions, and indicate the need to minimize new introductions of exotic species, even if they are already present in the introduced range. [ABSTRACT FROM AUTHOR]

Hybridization of sympatric closely related species may sometimes lead to introgression and speciation. The sister species Helicoverpa armigera and Helicoverpa assulta both use (Z)-11-hexadecenal and (Z)-9-hexadecenal as sex pheromone components but in reversed ratios. Female H. armigera and male H. assulta could hybridize and produce fertile male hybrids, which can then backcross with females of the two parent species to get backcross lines in the laboratory. In this study, we compared the olfactory responses to pheromone compounds in the periphery and in the antennal lobes (ALs) of males of the two species, as well as of their hybrids and backcrosses. Single-sensillum recordings were carried out to explore characteristics of male-specific sensilla on the antennae, and in vivo calcium imaging combined with digital 3D-reconstruction was used to describe what happens in the macroglomerular complex (MGC) of the AL. The results show that the population ratio of the two male-specific types of olfactory sensory neurons responding to two sex pheromone components are controlled by a major gene, and that the allele of H. armigera is dominant. Consistently, the study of the representative areas activated by sex pheromone components in the ALs further support the dominance of H. armigera. However, the topological structure of the MGC in the hybrid was similar but not identical to that in H. armigera. All subtypes of male-specific sensilla identified in the two species were found in the male hybrids and backcrosses. Moreover, two new subtypes with broader response spectra (the expanded A subtype and the expanded C subtype) emerged in the hybrids. Based on the inheritance pattern of the pheromone sensory system, we predict that when hybridization of female H. armigera and male H. assulta occurs in the field, male hybrids would readily backcross with female H. armigera, and introgression might occur from H. assulta into H. armigera through repeated backcrossing. [ABSTRACT FROM AUTHOR]

Attention has been focused on the utilization of useful genetic resources in developing elite parental lines and making Jatropha hybrids for incorporating superior traits in Jatropha germplasm. Evaluations of morphological and yield contributing traits in F1 progeny have been made and hybrids having high seed yield and oil content have been identified. Multiplication of these hybrid lines was undertaken through stem cuttings. To develop Jatropha hybrids through intraspecific hybridization, twenty three accessions were collected from different parts of the country and grown on wastelands under semi-arid conditions. All the germplasm were assessed for desirable traits and cross-combinations were made between identified accessions of J. curcas based on considerable seed yield and higher oil content. Growth and yield performance was recorded from plants raised through stem cuttings of various cross combinations and studies were undertaken in four leading hybrids along with their respective parents. Two years old plants developed from the cross IC565735 × IC565739 proved to be the best with 75 % fruit set, 300 g seed yield per plant and 39.02 % oil content. [ABSTRACT FROM AUTHOR]

Hybrids pre-zygotic barriers between wild forms of cowpea. The wild forms of cowpea, Vigna unguiculata, constitute an important gene pool insufficiently exploited for the improvement of the cultivated form. In order to promote the use of these wild forms in the genetic improvement programmes, we undertook to understand the various incompatibility reactions which appear in the crosses between wild forms. Efforts were concentrated to understand the incompatibility barriers in the hybridizations between subsp. baoulensis NI 933 and the other wild forms of V. unguiculata. Thanks to the use of the aniline blue fluorescence, we observed a high frequency of pre-zygotic barriers. They appear in three sites, i.e. the higher and lower third of the style, and within the ovary. However, these incompatibility barriers are not absolute. Indeed, in our hybridizations, more than 4% of the ovules were fertilized in the various studied combinations.

* Premise of the study: The introduction of nonnative taxa into areas occupied by conspecifics can lead to local extinction of native taxa via habitat modification and competitive dominance, and be exacerbated by outbreeding depression or the formation of invasive hybrid lineages following intraspecific gene flow. The expansion of Eurasian Phragmites australis into tidal wetlands of North America has been accompanied by a dramatic decline of native P. australis, with few relic populations remaining along the Atlantic coastline of the United States, particularly in the Virginia portion of the Chesapeake Bay. * Methods: We sampled populations from the York River and its two major tributaries to determine the pattern of Phragmites invasion and identify remnant native populations that warrant conservation. We used chloroplast DNA haplotypes and nuclear DNA microsatellite profiles to classify individuals as belonging to the native or introduced lineage. * Key results: Although native Phragmites stands were identified in the brackish upstream reaches of the two York River tributaries, the majority of Phragmites stands surveyed contained the introduced lineage. We also identified a single putative hybrid plant, based on its microsatellite profile. This plant possessed the native cpDNA haplotype and was located in an otherwise native Phragmites stand that is adjacent to an isolated patch of introduced Phragmites. * Conclusions: Although evidence of field hybridization between native and introduced lineages of Phragmites in North America is still relatively rare, the continued encroachment of the introduced lineage into native wetlands may increase the likelihood of future hybrid formation. Careful genetic monitoring to identify remnant native and potential hybrid Phragmites is essential for prioritizing ongoing management efforts. [ABSTRACT FROM AUTHOR]

In this study, the phylogenetic relationships between cachaça strains of Saccharomyces cerevisiae isolated from different geographical areas in Brazil were obtained on the basis of sequences of one mitochondrial ( COX2) and three nuclear ( EGT2 , CAT8 , and BRE5) genes. This analysis allowed us to demonstrate that different types of strains coexist in cachaça fermentations: wine strains, exhibiting alleles related or identical to those present in European wine strains; native strains, containing alleles similar to those found in strains isolated from traditional fermentations from Latin America, North America, Malaysian, Japan, or West Africa; and their intraspecific hybrids or 'mestizo' strains, heterozygous for both types of alleles. Wine strains and hybrids with high proportions of wine-type alleles predominate in southern and southeastern Brazil, where cachaça production coexists with winemaking. The high frequency of 'wine-type' alleles in these regions is probably due to the arrival of wine immigrant strains introduced from Europe in the nearby wineries due to the winemaking practices. However, in north and northeastern states, regions less suited or not suited for vine growing and winemaking, wine-type alleles are much less frequent because 'mestizo' strains with intermediate or higher proportions of 'native-type' alleles are predominant. [ABSTRACT FROM AUTHOR]

Ascochyta blight (AB) caused by Ascochyta rabiei (Pass.) Labr. and Botrytis grey mould (BGM) caused by Botrytis cinerea (Pers. ex Fr.) are important diseases of the aerial plant parts of chickpea in most chickpea growing areas of the world. Although conventional approaches have contributed to reducing disease, the use of new technologies is expected to further reduce losses through these biotic stresses. Reliable screening techniques were developed: ‘field screening technique’ for adult plant screening, ‘cloth chamber technique’ and ‘growth chamber technique’ for the study of races of the pathogen and for segregating generations. Furthermore, the ‘cut twig technique’ for interspecific population for AB and BGM resistance was developed. For introgression of high levels of AB and BGM resistance in cultivated chickpea from wild relatives, accessions of seven annual wild Cicer spp. were evaluated and identified: C. judaicum accessions 185, ILWC 95 and ILWC 61, C. pinnatifidum accessions 188, 199 and ILWC 212 as potential donors. C. pinnatifidum accession188 was crossed with ICCV 96030 and 62 F9 lines resistant to AB and BGM were derived. Of the derived lines, several are being evaluated for agronomic traits and yield parameters while four lines, GL 29029, GL29206, GL29212, GL29081 possessing high degree of resistance were crossed with susceptible high yielding cultivars BG 256 to improve resistance and to undertake molecular studies. Genotyping of F2 populations with SSR markers from the chickpea genome was done to identify markers potentially linked with AB and BGM resistance genes. In preliminary studies, of 120 SSR markers used, six (Ta 2, Ta 110, Ta 139, CaSTMS 7, CaSTMS 24 and Tr 29) were identified with polymorphic bands between resistant derivative lines and the susceptible parent. The study shows that wild species of Cicer are the valuable gene pools of resistance to AB and BGM. The resistant derivative lines generated here can serve as good pre-breeding material and markers identified can assist in marker assisted selection for resistance breeding.

Previous studies on the phylogeography of the meadow spittlebug Philaenus spumarius (L.) (Hemiptera: Aphrophoridae) suggest the existence of a contact zone of its main phylogenetic lineages along mountain chains in Europe and western Asia. This study presents a detailed examination of the population genetics of P. spumarius within the Carpathian Mountains. The main objective was to determine whether the populations inhabiting that area consist of individuals belonging to different genetic units and whether the observed pattern could be an example of secondary contact zone which formed after incomplete allopatric speciation. Specimens from six transects across the Carpathian arc were examined. The mitochondrial phylogeography of the meadow spittlebug in the examined area clearly shows that individuals from both main clades meet and mix there. Representatives of all three main EF1-α clades were also found. The present distribution of the main clades with a zone of overlap along the mountain ranges may suggest that these phylogenetic lineages form a young hybrid zone. Moreover, a limited number of individuals were shown to possess heteroplasmic mitochondrial DNA, which gives additional support to intraspecific hybridization. P. spumarius could be used in future work as an excellent model species in investigating population genetics, intraspecific hybridization, and speciation in progress. [ABSTRACT FROM AUTHOR]

Hybridization is a prominent process among natural plant populations that can result in phenotypic novelty, heterosis, and changes in gene expression. The effects of intraspecific hybridization on F1 hybrid gene expression were investigated using parents from divergent, natural populations of Cirsium arvense, an invasive Compositae weed. Using an RNA-seq approach, the expression of 68,746 unigenes was quantified in parents and hybrids. The expression levels of 51% of transcripts differed between parents, a majority of which had less than 1.25× fold-changes. More unigenes had higher expression in the invasive parent (P1) than the noninvasive parent (P2). Of those that were divergently expressed between parents, 10% showed additive and 81% showed nonadditive (transgressive or dominant) modes of gene action in the hybrids. A majority of the dominant cases had P2-like expression patterns in the hybrids. Comparisons of allele-specific expression also enabled a survey of cis- and trans-regulatory effects. Cis- and trans-regulatory divergence was found at 70% and 68% of 62,281 informative single-nucleotide polymorphism sites, respectively. Of the 17% of sites exhibiting both cis- and trans-effects, a majority (70%) had antagonistic regulatory interactions (cis x trans); trans-divergence tended to drive higher expression of the P1 allele, whereas cis-divergence tended to increase P2 transcript abundance. Trans-effects correlated more highly than cis with parental expression divergence and accounted for a greater proportion of the regulatory divergence at sites with additive compared with nonadditive inheritance patterns. This study explores the nature of, and types of mechanisms underlying, expression changes that occur in upon intraspecific hybridization in natural populations. [ABSTRACT FROM PUBLISHER]

Inter- or intraspecific hybridization is the first step in transferring exogenous traits to the germplasm of a recipient crop. One of the complicating factors is the occurrence of epigenetic modifications of the hybrids, which in turn can change their gene expression and phenotype. In this study we present an analysis of epigenome changes in rice hybrids that were obtained by crossing rice cultivars, most of them of indica type and Thai origin. Comparing amplified fragment length polymorphism (AFLP) fingerprints of twenty-four cultivars, we calculated Nei's indexes for measuring genetic relationships. Epigenetic changes in their hybrids were established using methylation-sensitive AFLP fingerprinting and transposon display of the rice transposable elements (TEs) Stowaway Os-1 and Mashu, leading to the question whether the relationship between parental genomes is a predictor of epigenome changes, TE reactivation and changes in TE methylation. Our study now reveals that the genetic relationship between the parents and DNA methylation changes in their hybrids is not significantly correlated. Moreover, genetic distance correlates only weakly with Mashu reactivation, whereas it does not correlate with Stowaway Os-1 reactivation. Our observations also suggest that epigenome changes in the hybrids are localized events affecting specific chromosomal regions and transposons rather than affecting the genomic methylation landscape as a whole. The weak correlation between genetic distance and Mashu methylation and reactivation points at only limited influence of genetic background on the epigenetic status of the transposon. Our study further demonstrates that hybridizations between and among specific japonica and indica cultivars induce both genomic DNA methylation and reactivation/methylation change in the Stowaway Os-1 and Mashu transposons. The observed epigenetic changes seem to affect the transposons in a clear manner, partly driven by stochastic processes, which may account for a broader phenotypic plasticity of the hybrids. A better understanding of the epigenome changes leading to such transposon activation can lead to the development of novel tools for more variability in future rice breeding. [ABSTRACT FROM AUTHOR]

In the framework of biological control, the selection of effective natural enemies determines the final pest control. Thus, the genetic improvement of biocontrol agents could enhance the efficiency of biocontrol programs. Although promising, this approach has rarely been applied in this field. At the intraspecific level, hybridization between divergent populations of biocontrol agents is expected to promote hybrid vigor (heterosis), but it is not clear to what extent. An even more difficult task is the ability to predict the fitness of hybrids from the biological characteristics of their parents. We investigated these general questions by crossing seven populations of the parasitoid wasp Trichogramma chilonis (Hymenoptera: Trichogrammatidae). Our results show different levels of mating compatibilities among populations, including asymmetric or almost complete reproductive isolation. Hybrids' performance (fitness of the F1 generation) ranges from inbreeding depression to heterosis. It was possible, to some extent, to predict hybrid fitness from pairwise genetic and phenotypic distances among parents, in accordance with the 'dominance' hypothesis. This may provide general guidelines for the genetic improvement of biological control agents. [ABSTRACT FROM AUTHOR]

Hybridization is an important evolutionary mechanism that can increase the fitness and adaptive potential of populations. A growing body of evidence supports its importance as a key factor contributing to rapid evolution in invasive species, but the effects of hybridization have rarely been assessed in intentionally introduced biological control agents. We investigated hybrids between a Swiss and an Italian population of the beetle, Longitarsus jacobaeae, a biological control agent of Jacobaea vulgaris, by reciprocally crossing individuals in the laboratory. Phenological traits of F1 and F2 hybrid lineages showed intermediate values relative to their parental populations, with some maternal influence. Fitness of the F2 generation, measured as lifetime fecundity, was higher than that of the Italian parent in one of the lineages and higher than that of either parent in the other hybrid lineage. The increased fecundity of hybrids may benefit tansy ragwort biological control by increasing the establishment success and facilitating a more rapid population buildup in the early generations. Even though the long-term consequences of hybridization in this and other systems are hard to predict, intentional hybridization may be a useful tool in biological control strategies as it would promote similar microevolutionary processes operating in numerous targeted invasive species. [ABSTRACT FROM AUTHOR]

Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), is a highly successful invasive species in the continental United States, Hawaiian archipelago, several Caribbean Islands, Australia, Bermuda, and a number of other countries worldwide. It also is one of only a few invasive intraspecific hybrids that has been well characterized genetically. The natural enemy complex of Brazilian peppertree includes two thrips and two psyllids that appear to be highly adapted to specific haplotypes or their hybrids. Successful biological control of Brazilian peppertree will require careful matching of the appropriate natural enemies with their host plant genotypes. The Brazilian peppertree model reviewed here could provide a useful framework for studying biological control agents on other invasive weed species that have exhibited intraspecific hybridization. [ABSTRACT FROM AUTHOR]