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Dichanthium annulatum is a popular halophyte C4 perennial forage crop of semi-arid tropics that reproduces apomictically. In vitro plant regeneration in apomictic species helps in producing new germplasm that can supplement existing breeding program. Field-collected seeds and in vitro shoot apices were tested for response to 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP) for initiation of somatic embryogenesis (SE) and direct shoot organogenesis (DSO). Explants produced callus on Murashige and Skoog (MS) medium with varying level of 2,4-D and 0.5 mgL–1 BAP. After 4th sub-culture, yellowish brown turns into white nodular callus tissue with a friable appearance, which exhibited the highest percentage of embryogenic callus induction on MS medium with 3.0 mgL–1 2,4-D and 0.5 mgL–1 BAP, was transferred to MS with BAP or kinetin and 0.125 mgL–1 2,4-D to promote somatic embryo germination into plantlet. The developmental stages of SE were identified using scanning electron microscopy and histology. Multiple shoots were observed with the combinations of BAP or kinetin with 2,4-D. The highest number of shoots (27) occurred on MS medium comprising 4.0 mgL–1 BAP and 0.125 mgL–1 2,4-D. In vitro plantlet was rooted on MS medium with 0.4% charcoal. The rooted 80% plants could be acclimatized and established in soil, as they showed healthy growth and fertility. [ABSTRACT FROM AUTHOR]

The low efficiency of somatic embryo induction, proliferation, germination, and conversion to plantlets is a major problem in walnut. In this study, we used the cotyledons of immature embryos of apomictic seeds in walnut plus trees 'Y17' as explants. The optimum medium and culture conditions of somatic embryo induction, proliferation, and germination were tested through comparative experiments. The results showed that the optimum formula for somatic embryo induction, proliferation, and germination medium was DKW medium with 1.0 mg L−1 6-BA, 2.0 mg L−1 KT, and 0.01 mg L−1 IBA, DKW medium with 30–40 g L−1 sucrose and 7–8 g L−1 agar, and DKW medium with 2.0 mg L−1 concentrations of GA3, respectively. Meanwhile, the optimum time of seedling training was 36 h, and the substrate ratio was perlite: peat soil: vermiculite (1: 2: 1) after plant transplanting. The inter simple sequence repeat marker banding patterns of the primary embryo, secondary embryo and regenerated plants were all identical to that of the mother plant and proved the genetic stability of regenerated plants. An excellent walnut tissue culture system from walnut somatic embryo to the whole plant was formed, which can accelerate the speed of walnut genetic improvement. Key message: An excellent walnut tissue culture system from walnut somatic embryo to the whole plant was formed, which can accelerate the speed of walnut genetic improvement. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the vegetative, reproductive, production, and forage quality characteristics of three Buffel grass varieties from northern Tamaulipas. Design/Methodology/Approach: A pot trial was established under open field conditions, at CERIBCIRNE-INIFAP in Río Bravo, Tamaulipas, on 04/15/2016 and 03/10/2017; the experiment was carried out with a completely randomized design, with 30 replications per material. The morphological, reproductive, production, and chemical composition characteristics of the Milenio, Regio, and Titán Buffel grass varieties forage were evaluated. Results: The year accounted for 62.3% of the variation in the stem and leaf characteristics. The genotype contributed 35.4% and G*Y interaction, less than 2%. Regarding the reproductive variables, the genotype accounted for 62% of the results, the G*Y interaction, 25%, and the year, 13%. The genotype and the year accounted for 44% and 47% of the variance in forage production and quality, respectively. The G*Y interaction had no statistical effect. Limitations/Implications: The evaluation was carried out under pot conditions, which implies that the roots of the plants have limited growth and that the expression of some of the characteristics of the material may be restricted. Findings/Conclusions: The major differences between the three varieties were found in their morphological characteristics: duration of the flowering stage, reproductive stems proportion, panicle length, exertion of the panicle from the main stem, number of florets per panicle, and seed weight. [ABSTRACT FROM AUTHOR]

• In this study, we developed an efficient, easy and reproducible in vitro plant regeneration through callus mediated somatic embryogenesis and direct multiple shoot induction in two genotypes of Pennisetum pedicellatum. • This is the first report on somatic embryogenesis and direct multiple shoot induction in Deenanath grass. This protocol is highly suitable for optimizing the genetic transformation of Pennisetum pedicellatum. • This protocol is easy to follow and it can be used for production of large number of in vitro plantlets for commercial production. • The somaclonal variations induced through this protocol can be heritably fixed in this grass due to its predominant apomictic mode of reproduction. Pennisetum pedicellatum Trin. is a C 4 tropical perennial forage grass known as Deenanath grass holding great potential to address vital, puzzling issues such as bio-economy, human health and the environment. Genetic complexity not only is a big barrier in selection and breeding practices but also restricts harnessing of the full potential of this multipurpose fodder crop. By optimizing a rapid, effective and consistent in vitro regeneration protocol through callus mediated and direct shoot organogenesis, we can multiply these plants for producing a large amount of biomass. Calli were induced from mature seeds and shoot apices of two genotypes on Murashige and Skoog (MS) medium containing different levels of 9.0–22.5 µM 2,4-Dichlorophenoxyacetic acid (2,4-D) and a constant level of 2.22 µM N6-benzyladenine (BA). Seventy-one percent of the calli turned embryogenic when 2,4-D (2.25 µM) was reduced in the medium. Somatic embryogenesis was accomplished on MS medium with an increased level of either BA (4.4–17.6 µM) or kinetin (4.6–18.4 µM) along with 0.56 µM 2,4-D. Ultra-structural and histological studies indicated globular, scutellar and coleoptilar somatic embryos. A maximum of 82.7±1.6% plant regeneration was accomplished from seed explants on MS medium containing 8.8 µM BA and 0.56 µM 2,4-D. Multiple shoots were induced on MS media containing either BA (4.4–18.0 µM) or kinetin (4.6–18.4 µM) along with 0.56 µM 2,4-D using shoot apices. A maximum of 22.1±0.45 shoots per shoot apex was produced on MS medium containing 8.8 µM BA and 0.56 µM 2,4-D. Successful rooting of healthy shoots generated through both the pathways could be optimized on ½MS medium containing 0.4% charcoal. Complete plants could be hardened in plastic pots and were well established on field conditions. In vitro regeneration was established for the first time successfully, which would be very useful for genetic improvement of this apomictic species through transgenic approach. [ABSTRACT FROM AUTHOR]

Some thrips species are considered as model insect organisms to study reproductive biology since some closely related (sub) species were mainly reproducing by arrhenotoky, thelytoky and in some rare cases as deuterotoky. As other insect species, thrips are associated with endosymbiotic bacteria and this bacteria has led to manipulating their reproductive biology. The main goal of this paper is to review the reproductive modes, potential reproductive manipulators and their strategies to change the reproductive biology of thrips species. Thrips species are reproducing through, arrhenotoky, thelytoky and deuterotoky. Wolbachia, Cardinium, Rickettsia and Spiroplasma have been detected in the reproductive organs of some thrips species and the most common insect reproductive manipulators by causing cytoplasmic incompatibility, thelytokous parthenogenesis, male killing and feminization. [ABSTRACT FROM AUTHOR]

A highly reproducible plant regeneration protocol through somatic embryogenesis and shoot organogenesis has been developed for Cenchrus ciliaris. Three explants (seeds, shoot apices, and immature inflorescences) of four genotypes (IG-3108, IG-718, IG-74, and DBC15-8/32/10) were used for callus induction and plant regeneration. The highest rate of callus formation was found using Murashige and Skoog (MS) medium supplemented with 0.5 mg L−1 benzylaminopurine (BA) and 3.0 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D). The largest number of somatic embryos was generated with the addition of 400 mg L−1 L-proline, 400 mg L−1 L-glutamine, and 300 mg L−1 casein hydrolysate. Somatic embryos were successfully germinated on MS medium with 3.0 mg L−1 BA and 0.25 mg L−1 2,4-D. In vitro plant regeneration was accomplished through somatic embryogenesis using all three explants. Ultra-structural features of somatic embryos confirmed proper formation and ontogeny. [ABSTRACT FROM AUTHOR]

Guggul ( Commiphora wightii ) is a critically endangered medicinal plant distributed in arid and semi-arid agro-climatic zones of Northern-west India. Information on genetic diversity of C. wightii using DNA markers even though reported is limited to Rajasthan and Haryana populations and that too without considering its reproductive behaviour. In the present study, we are reporting for the first time the genetic diversity vis-a-vis its reproductive behaviour by including more number of accessions from Gujarat, which is the only place in India where sexual populations are distributed. We used RAPD and ISSR markers since genome sequence information is lacking in the species. Twenty four RAPD primers and 16 ISSR primers amplified a total of 185 and 128 reproducible DNA fragments, respectively with fragment sizes ranged from 200 to 3000 bp. RAPD analysis showed higher polymorphism (80%) in comparison to ISSR (69%). Jaccard's coefficient of similarity showed that pair-wise genetic similarity coefficients ranged from 46 to 98.3% in RAPD analysis, whereas it ranged from 47.8 to 98.6% in ISSR analysis. The results showed that the trend of genetic variation was not strictly correlated to the geographical locations, but was related to the reproductive behaviour of the populations. The diversity was somewhat low in Rajasthan populations where only apomictic populations are distributed. Populations of maximum genetic diversity along with sexual forms were found distributed in Gujarat populations, especially in Kutchh, Dwarka, Jamnagar and Porbandar populations. Hence the study indicated these areas as the original areas of the species distribution from where it was spread to the other parts of Gujarat and Rajasthan. [ABSTRACT FROM AUTHOR]

Morphological variation in triploid apomicts of Amorphophallus muelleri has been postulated as low. Here, we present for the first time macroscopic variation in floral morphology from natural and gibberellin treatments. Agamosporous (A. muelleri) exhibited morphological variations on 35 out of 45 floral characters. Organ variation was apparent on peduncle, spathe, stigma, carpel, and appendix; that could relate to different genetic background. It seems that gibberellin application at initial stage of flowering increased the existing morphological variation; causing phenotypic plasticity in three characters, i.e., sheath length, disposition of second spathe and degree of limb apex shape. Present study implies that floral characters can be used as key to determine true-to-type of A. muelleri. Further extensive research is needed to clarify the variation in apomict of A. muelleri using approaches such as metabolomics and hormonal dynamics during flowering. [ABSTRACT FROM AUTHOR]

Mangosteen (Garcinia mangostana Linn.) is an ultra-tropical tree characterized by its unique dark purple fruits with white flesh. The xanthone-rich purple pericarp tissue contains valuable compounds with medicinal properties. Following previously reported genome sequencing of a common variety of mangosteen [1], we performed another whole genome sequencing of a commercially popular variety of this fruit species (var. Mesta) for comparative analysis of its genome composition. Raw reads of the DNA sequencing project were deposited to SRA database with the accession number SRX2709728.

The genetic variation and relationships of the mangosteen ( Garcinia mangostana L.) were observed across mangosteen populations in Java, Indonesia using newly identified microsatellite loci and morphological characters. In this study, we developed an improved protocol to isolate microsatellite loci, named Selective Repeats from AFLP Sequence, by using a hybridized membrane. Twenty microsatellite loci were evaluated using 78 individuals from five mangosteen populations, and we successfully amplified four closely related Garcinia species, including G. malaccensis, G. hombroniana, G. celebica, and G. porrecta. Eight loci were monomorphic and the others were polymorphic. Sixty-nine alleles were found, with 3.491 per locus on an average. Genetic diversity (Hʹ) was calculated with an average across loci within population (Hʹ) as 0.39, an average loci across many populations (Hʹ) as 0.444, and genetic differentiation (Fʹ) as 0.147. Furthermore, based on morphological characters, mangosteen individuals from four populations including Leuwiliang, Wanayasa, Puspahiang, and Kaligesing also had morphologically distinct fruit weight, rind weight, and rind thickness among populations. The study also elucidated the dispersal pattern of mangosteen in Java; the source of the genotype mangosteen in Java population was the Wanayasa population. In addition, we found evidence of tetraploidy in mangosteen. These results have potential applications in future breeding, conservation studies, and genetic assessment of mangosteen and their closely related species. [ABSTRACT FROM AUTHOR]

Polycomb group (PcG) protein MEDEA (MEA), one of the Enhancer of Zeste [E(z)], represses endosperm development in Arabidopsis until fertilization occurs. The Eulaliopsis binata is an apomictic species that forms endosperm asexually. Up to now, little is known about their homologs in apomictic plants. Here, E(z)-like genes EbEZ1 and EbEZ2 were cloned from Eulaliopsis. The EbEZs were ubiquitously expressed in vegetative and reproductive organs while their high mRNAs were accumulated in seed. In addition, up-regulated expression of EbEZ1 in mature seed was in accompanied with hypomethylation of the promoter. Transgenic EbEZ1 rice lines produced decreased seed setting and abnormal endosperm and embryo. Moreover, the expression level of genes which were co-expressed with OsCLF (a homolog of EbEZ1) were up-regulated, indicating that EbEZ1 may integrate into the regulatory network of rice endogenous PcG complex which was supported by EbEZ1 interaction in vitro with the rice FERTILIZATION INDEPENDENT ENDOSPERM 1 (FIE1) PcG protein. [ABSTRACT FROM AUTHOR]

Species with sexual and asexual life cycles may exhibit intraspecific differences in reproductive effort. The spatial separation of sexual and asexual lineages, called geographic parthenogenesis, is common in plants, animals, and algae. Mastocarpus papillatus is a well-documented case of geographic parthenogenesis in which sexuals dominate southern populations, asexuals dominate northern popula-tions, whereas mixed populations occur throughout central California. We quantified abundances and reproductive effort of sexual and asexual fronds and tetrasporophytes at eight sites in California to test the hypotheses that (1) reduced sexual reproduction at higher latitudes and tidal heights explains the observed geographic parthenogenesis and (2) reproductive effort (spore production per blade area) declines with increasing latitude. Abundances of all phases varied site-specifically. However, there was no geographic pattern of reproductive effort of fronds. Reproductive effort of fronds was greater in 2006 than in 2007 and correlated with sea surface temperatures. Sexual fronds exhibited greater reproductive effort than did asexual fronds and sexual reproductive effort was also inversely correlated with local upwelling index. Tetrasporophytes showed greater repro-ductive effort in northern sites, but total supply of tetraspores per m2 was greatest in the middle of the sampling range where crusts were more abundant. There was no decline of reproductive effort at higher latitudes. Geographic patterns of fecundity of life stages do not explain geographic parthe-nogenesis in M. papillatus. Site-specific differences in viability among spores or established thalli of different life cycles may explain their respective geographic distributions, as the sexual and asexual life cycles responded differently to environmental variations. [ABSTRACT FROM AUTHOR]

Species with sexual and asexual life cycles may exhibit intraspecific differences in reproductive effort. The spatial separation of sexual and asexual lineages, called geographic parthenogenesis, is common in plants, animals, and algae. Mastocarpus papillatus is a well-documented case of geographic parthenogenesis in which sexuals dominate southern populations, asexuals dominate northern popula-tions, whereas mixed populations occur throughout central California. We quantified abundances and reproductive effort of sexual and asexual fronds and tetrasporophytes at eight sites in California to test the hypotheses that (1) reduced sexual reproduction at higher latitudes and tidal heights explains the observed geographic parthenogenesis and (2) reproductive effort (spore production per blade area) declines with increasing latitude. Abundances of all phases varied site-specifically. However, there was no geographic pattern of reproductive effort of fronds. Reproductive effort of fronds was greater in 2006 than in 2007 and correlated with sea surface temperatures. Sexual fronds exhibited greater reproductive effort than did asexual fronds and sexual reproductive effort was also inversely correlated with local upwelling index. Tetrasporophytes showed greater repro-ductive effort in northern sites, but total supply of tetraspores per m2 was greatest in the middle of the sampling range where crusts were more abundant. There was no decline of reproductive effort at higher latitudes. Geographic patterns of fecundity of life stages do not explain geographic parthe-nogenesis in M. papillatus. Site-specific differences in viability among spores or established thalli of different life cycles may explain their respective geographic distributions, as the sexual and asexual life cycles responded differently to environmental variations. [ABSTRACT FROM AUTHOR]

Studies of genotype × environment interactions (G × E) and local adaptation provide critical tests of natural selection's ability to counter opposing forces such as gene flow. Such studies may be greatly facilitated in asexual species, given the possibility for experimental replication at the level of true genotypes (rather than populations) and the possibility of using molecular markers to assess genotype-environment associations in the field (neither of which is possible for most sexual species). Here, we tested for G × E in asexual dandelions ( Taraxacum officinale) by subjecting six genotypes to experimental drought, mown and benign (control) conditions and subsequently using microsatellites to assess genotype-environment associations in the field. We found strong G × E, with genotypes that performed poorly under benign conditions showing the highest performance under stressful conditions (drought or mown). Our six focal genotypes comprise > 80% of plants in local populations. The most common genotype in the field showed its highest relative performance under mown conditions (the most common habitat in our study area), and almost all plants of this genotype in the field were found growing in mowed lawns. Genotypes performing best under benign experimental conditions were found most frequently in unmown conditions in the field. These results are strongly indicative of local adaptation at a very small scale, with unmown microsites of only a few square metres typically embedded within larger mown lawns. By studying an asexual species, we were able to map genotypes with known ecological characteristics to environments with high spatial precision. [ABSTRACT FROM AUTHOR]

Abstract: Female sterile plants are ideal for isolating genes involved in megasporogenesis and for investigating gene functions. Engineered female and male sterilities in plants have been considered as a way to reduce the potential of invasive species by eliminating seed set and to prevent gene flow between genetically modified species. A dwarf mutant ‘PM2’ induced by carrying ‘Nassau’ Kentucky bluegrass seeds to outer space lost the ability to produce seeds under either field conditions or artificial flower induction, whereas the untreated control was normal. Comparative study of microspore, macrospore, and embryo sac at different developmental stages along with controlled pollination showed that the PM2 mutant is likely both male and female sterile. The apoporous embryo development in PM2 aborted at globular stage prior to coleoptile formation. Multiple genes may be involved in the mutation based on the evidence observed from the morphology and anatomy of the mutant. [Copyright &y& Elsevier]

Species of the genus Mastocarpus exhibit two distinct life cycles, a sexual alternation of generations and an obligate, asexual direct life cycle that produces only female upright fronds. In the intertidal red alga, M. papillatus (Kützing) sexual fronds dominate southern populations and asexual fronds dominate northern populations along the northeast Pacific coast, a pattern of spatial separation called geographic parthenogenesis. Along the central coast of California, sexual and asexual variants occur in mixed populations, but it is not known whether they are spatially separated within the intertidal zone at a given site. We investigated reproductive phenologies and analyzed patterns of spatial distributions of sexual and asexual M. papillatus at three sites in this region. Sexual M. papillatus were aggregated lower on the shore at two sites and only reproduced during part of a year, while asexual M. papillatus occurred throughout the intertidal range at all sites and reproduced throughout the year. The distribution patterns of sexual and asexual M. papillatus are consistent with a hypothesis of shoreline topography influencing their dynamics of dispersal and colonization. Spatial and temporal partitioning may contribute to the long-term coexistence of sexual and asexual life histories in this, and other, species of Mastocarpus. The occurrence of geographic parthenogenesis at multiple spatial scales in M. papillatus provides an opportunity to gain insight into the phenomenon. [ABSTRACT FROM AUTHOR]

Crossing experiments in Fragaria have frequently resulted in some matroclinal progeny. These have been attributed to either accidental selfing and/or pollen contamination, or apomixis. In this study 202 carefully controlled intra and interspecific crosses in Fragaria were made. No progeny were produced from 164 interploid crosses made between diploids, hexaploids and octoploids but 38 intraploid crosses resulted in 904 F1 plants, of which 42 (4.6%) were found to be morphologically matroclinal. All matroclinal progeny subsequently studied by RAPDs were found to be hybrids and not apomicts. The absence of apomixis among matroclinal progeny in this study casts doubt on previous reports of apomixis in Fragaria. Our results showed that the complete morphological similarity of progeny to the seed parent, even in recessive characteristics, cannot therefore be taken as evidence of apomixis, and may rather indicate the heterozygosity of the pollen parent, emphasising the need to use DNA markers for confirmation of apomixis. [ABSTRACT FROM AUTHOR]

Buffel grass ( Cenchrus ciliaris L.) is an important apomictic grass used as forage for ruminant livestock. Biotechnological methods provide opportunities for producing new germplasm. Mature embryos of fourteen buffel grass apomictic cultivars (2 n = 4 x = 36) were used to induce embryogenic callus formation using a basal medium supplemented with 3% sucrose and with the testing of five concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and four concentrations of 6-benzylaminopurine (BAP). The effects of cultivar and culture medium on callus induction and plant regeneration were evaluated. Significant differences were observed among the fourteen cultivars and the five concentrations of 2,4-D ( P < 0·01). Values for embryogenic callus production varied from 0 to 86·7. Most cultivars showed the highest level of embryogenic callus production on the medium with the concentration of 3 mg L−1 2,4-D. The addition of different BAP concentrations in combination with 2,4-D in the medium inhibited embryogenic callus growth and did not permit plant regeneration. The data clearly demonstrated that the genotype and concentrations of 2,4-D had significant effects both on the frequency of embryonic callus formation from mature embryos and on the subsequent efficiency of plant regeneration of apomictic cultivars of buffel grass. Cultivars Biloela and Nunbank showed the greatest efficiency in in vitro culture response. [ABSTRACT FROM AUTHOR]

Mangosteen ( Garcinia mangostana Linn.) is an ultra-tropical tree characterized by its unique dark purple fruits with white flesh. The xanthone-rich purple pericarp tissue contains valuable compounds with medicinal properties. Following previously reported genome sequencing of a common variety of mangosteen [1], we performed another whole genome sequencing of a commercially popular variety of this fruit species (var. Mesta) for comparative analysis of its genome composition. Raw reads of the DNA sequencing project were deposited to SRA database with the accession number SRX2709728.

In this dataset, we distinguish 15 accessions of Garcinia mangostana from Peninsular Malaysia using Fourier transform-infrared spectroscopy coupled with chemometric analysis. We found that the position and intensity of characteristic peaks at 3600-3100 cm(-) (1) in IR spectra allowed discrimination of G. mangostana from different locations. Further principal component analysis (PCA) of all the accessions suggests the two main clusters were formed: samples from Johor, Melaka, and Negeri Sembilan (South) were clustered together in one group while samples from Perak, Kedah, Penang, Selangor, Kelantan, and Terengganu (North and East Coast) were in another clustered group.

Mangosteen (Garcinia mangostana Linn.) is a tropical tree mainly found in South East Asia and considered as "the queen of fruits". The asexually produced fruit is dark purple or reddish in color, with white flesh which is slightly acidic with sweet flavor and a pleasant aroma. The purple pericarp tissue is rich in xanthones which are useful for medical purposes. We performed the first genome sequencing of this commercially important fruit tree to study its genome composition and attempted draft genome assembly. Raw reads of the DNA sequencing project have been deposited to SRA database with the accession number SRX1426419.

Species with sexual and asexual life cycles may exhibit intraspecific differences in reproductive effort. The spatial separation of sexual and asexual lineages, called geographic parthenogenesis, is common in plants, animals and algae. Mastocarpus papillatus is a well-documented case of geographic parthenogenesis in which sexuals dominate southern populations, asexuals dominate northern populations, while mixed populations occur throughout central California. We quantified abundances and reproductive effort of sexual and asexual fronds and tetrasporophytes at eight sites in California to test the hypotheses that (1) reduced sexual reproduction at higher latitudes and tidal heights explains the observed geographic parthenogenesis and (2) reproductive effort (spore production per blade area) declines with increasing latitude. Abundances of all phases varied site-specifically. However, there was no geographic pattern of reproductive effort of fronds. Reproductive effort of fronds was greater in 2006 than in 2007 and correlated with sea surface temperatures. Sexual fronds exhibited greater reproductive effort than did asexual fronds and sexual reproductive effort was also inversely correlated with local upwelling index. Tetrasporophytes showed greater reproductive effort in northern sites, but total supply of tetraspores per m 2 was greatest in the middle of the sampling range where crusts were more abundant. There was no decline of reproductive effort at higher latitudes. Geographic patterns of fecundity of life stages do not explain geographic parthenogenesis in M. papillatus . Site-specific differences in viability among spores or established thalli of different life cycles may explain their respective geographic distributions, as the sexual and asexual life cycles responded differently to environmental variations.