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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]

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]

• 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]

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]

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]

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]

* 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]

• Premise of the study: Pyrus calleryana Decne., an ornamental tree species introduced from China, is a relatively new invasive that has only recently begun to spread across the United States after intraspecific hybridization between cultivars. The function of such hybridization in the evolution of invasiveness is still relatively understudied, especially with respect to the initial establishment and persistence of invasive genotypes. Multiple introductions of genetically divergent populations or cultivars may benefit from new genetic combinations created during hybridization events and/or release from Allee effects in founder populations. • Methods: We quantified the outcome of intraspecific hybridization between cultivars of P. calleryana in a common garden. Measures of the reproductive success and establishment ability of their early- and advanced-generation hybrid offspring were collected to assess the likelihood of particular cultivar genotypes to establish in invasive populations. These traits also were compared between cultivated and invasive parents to identity any generational differences in invasive potential. • Key results: Differences were detected in measures of reproductive ability, but no group emerged as consistently more fecund. Advanced-generation hybrids also had significantly less biomass, indicating a reduction in hybrid performance relative to that of the cultivated progeny. • Conclusion: Ultimately, this study indicates that increased spread of P. calleryana has been initiated by introduction of multiple cultivar types and subsequent widespread planting and is not the result of an inherent fitness advantage of hybrid progeny. [ABSTRACT FROM AUTHOR]

Abstract: Wintersweet [Chimonanthus praecox (L.) Link] (n =11), a dichogamous species, is a famous traditional fragrant flower plant in China. We used AFLPs and ISSR to construct a genetic linkage map on a pseudo-F2 population of wintersweet derived from a cross between the individuals H4 and H29. A total of 370 polymorphism markers was generated from 12 AFLP primer combinations and 9 ISSR primers. Two separate female and male maps were constructed using 84 female-specific and 51 male-specific testcross markers, respectively. The maternal H4 map included 80 markers ordered in 12 linkage groups; while the paternal H29 map had 47 markers in 8 linkage groups. At a minimum logarithm of the odds (LOD) score of 3.0 and maximum map distance of 50cM, the female map covered 2417.8cM, with an average distance of 25.61cM and maximum map distance of 48.2cM between two loci. In contrast, the male map covered 1184.2cM, with an average distance of 25.7cM and maximum map distance of 49.0cM between two loci. These genetic maps will serve as a framework for mapping QTLs and provide basic information for future molecular breeding studies. [Copyright &y& Elsevier]

Long-distance transplantation of seed material as done in restoration programs has raised concerns about the risks associated with the introduction of maladapted genotypes that may hybridize with neighboring native conspecifics and decrease local population fitness (outbreeding depression). We studied the consequences of gene flow from foreign provenances into local populations in the common grassland species Plantago lanceolata (Plantaginaceae). Three generations of intraspecific hybrids (F1, F2, and backcross to the local plants) were produced by controlled crossings between local plants and plants from geographically or environmentally distant populations. Their performance was compared to that of within-population crosses in a field experiment. Early growth in some interpopulation hybrids was significantly reduced, and this decrease in performance was higher in progeny of crosses with the local population from a different habitat than with geographically distant populations. At the end of the growing season, most fitness-related traits of the interpopulation hybrids were close to the average of their parents. Crosses with low-performing foreign parents therefore resulted in reduced fitness of the hybrids compared to the local plants and dilution of local adaptation. We conclude that the introduction of maladapted populations from distant or ecologically distinct environments might, at least temporarily, decrease the fitness of neighboring local plants. [ABSTRACT FROM AUTHOR]