Accessions Of Wild Species Research Articles

Assessment of Simple Sequence Repeat (SSR) Markers Derived from Whole-Genome Sequence (WGS) of Mungbean (Vigna radiata L. Wilczek): Cross-Species Transferability and Population Genetic Studies in Vigna Species

The genus Vigna is pan-tropical, having more than 200 species with many desirable economically important traits. This study aimed to validate the in silico polymorphism of whole-genome-sequence-developed mungbean-specific SSR markers and their transferability among different Vigna species. The present study utilized a set of 200 SSR markers developed from the whole-genome sequence of mungbean and validated them using a diversity panel of 25 accessions that belong to 13 Vigna species. Out of 200 SSR markers, 130 markers (65%) were polymorphic across the various Vigna species, and the number of alleles amplified varied from 7 to 24. The SSR markers showed more than 90 percent transferability across the different Vigna species accessions. Utilizing allelic data, the 25 Vigna accessions were clustered into three groups using the unweighted pair group method with arithmetic mean (UPGMA). The two integral coalitions explained 50.79 and 15.42% of the total variance. The principal coordinate analysis (PCA) biplot graph and UPGMA-based neighbor-joining clustering diagram showed a similar pattern of Vigna accession distribution. A population structure assessment grouped the cultivated and wild species accessions into two sub-populations based upon a maximum delta K value of 144.79, which drew a sharp peak at K = 2. The estimated marker parameters, such as the polymorphic information content (0.09–0.84), marker index (0.091–3.342), and effective multiplex ratio (1.0–4.0), suggested their adequacy for several genetic studies, such as parental selection, hybrid testing, genetic mapping, and marker-aided breeding programs, for the genetic enhancement of species belonging to the Vigna genus.

Interspecific hybridization in niger (Guizotia abyssinica l.f. cass)

The study presents the results of successful establishment and interspecific hybridization of cultivated Niger (Guizotia abyssinica) with one of its wild allies, G. scabra. Out of four accessions of wild species collected from Kenya, two accessions (P3: EC1077609 and P4: EC1077610) could be successfully established that were used in interspecific crosses. Direct and reciprocal crosses were made (JNS-28 x P3; JNS-28 x P4) and adequate quantity of F1 seed was obtained in crosses of wild x cultivated. Morphological analysis of the F1 hybrids showed the vigorous nature of the interspecific hybrids and the results are presented.

Detection of trait donors and QTL boundaries for early blight resistance using local ancestry inference in a library of genomic sequences for tomato.

By conducting hierarchical clustering along a sliding window, we generated haplotypes across hundreds of re-sequenced genomes in a few hours. We leveraged our method to define cryptic introgressions underlying disease resistance in tomato (Solanum lycopersicum L.) and to discover resistant germplasm in the tomato seed bank. The genomes of 9 accessions with early blight (Alternaria linariae) disease resistance were newly sequenced and analyzed together with published sequences for 770 tomato and wild species accessions, most of which are available in germplasm collections. Identification of common ancestral haplotypes among resistant germplasm enabled rapid fine mapping of recently discovered quantitative trait loci (QTL) conferring resistance and the identification of possible causal variants. The source of the early blight QTL EB-9 was traced to a vintage tomato named 'Devon Surprise'. Another QTL, EB-5, as well as resistance to bacterial spot disease (Xanthomonas spp.), was traced to Hawaii 7998. A genomic survey of all accessions forecasted EB-9-derived resistance in several heirloom tomatoes, accessions of S. lycopersicum var. cerasiforme, and S. pimpinellifolium PI 37009. Our haplotype-based predictions were validated by screening the accessions against the causal pathogen. There was little evidence of EB-5 prevalence in surveyed contemporary germplasm, presenting an opportunity to bolster tomato disease resistance by adding this rare locus. Our work demonstrates practical insights that can be derived from the efficient processing of large genome-scale datasets, including rapid functional prediction of disease resistance QTL in diverse genetic backgrounds. Finally, our work finds more efficient ways to leverage public genetic resources for crop improvement.

Distribution of potato mosaic viruses on plants of the Petota Dumort. section of <i>Solanum</i> L. in the VIR collection

Background. Potato due to its vegetative propagation is affected by viruses, among which potato viruses Y (PVY), S (PVS) and M (PVM) are spread across all Russia’s territory. The VIR collection presents the diversity of the potato gene pool, including potato cultivars and related tuber-forming species. Diagnostics of viral infections in plants saved for several years by obtaining tuber reproductions is an important part of the work on the conservation and sustainable utilization of the potato gene pool. The purpose of the work was to evaluate the distribution of PVX, PVY, PVS and PVM on plants of potato cultivars and related Solanum spp. in the VIR field collection. Material and methods. Evaluation covered 315 accessions representing all groups of the potato gene pool. Diagnosis by enzyme-linked immunosorbent assay (ELISA) was carried out on plants that did not display symptoms of a virus infection. The Russian test system of RPA “BioTechnologies” and foreign one of Bioreba AG (Switzerland) were used. Statistical data processing was performed by the Statistica StatSoft 13 program. Results. Mosaic viruses are distributed with different frequencies on potato plants in the field collection: PVM dominates, detected in 64% of potato accessions; PVY is found in 41 %, PVX on 24 %, and PVS in 18 % of accessions. The connection between the botanical and taxonomic origin of potato accessions and their infection with viruses has been confirmed. Among wild species, more than half of accessions, while among cultivated species, only 5% are affected by XBK. PVM, on the contrary, was detected in a significant part (77–91%) of cultivated potato accessions. and much less frequently (16%) in accessions of wild species. Cvs, ‘Grand’, ‘Krasa Meshchery’, ‘Yantar’ and ‘Nur-Alem’, hybrids 99-1-3, 952-35 and 914-5-2018, accessions of wild species from North America, and cultivated species Solanum goniocalyx Juz. et Buk. (k-9922) are not affected by viruses.

Uncovering natural allelic and structural variants of OsCENH3 gene by targeted resequencing and in silico mining in genus Oryza

Plant breeding efforts to boost rice productivity have focused on developing a haploid development pipeline. CENH3 gene has emerged as a leading player that can be manipulated to engineer haploid induction system. Currently, allele mining for the OsCENH3 gene was done by PCR-based resequencing of 33 wild species accessions of genus Oryza and in silico mining of alleles from pre-existing data. We have identified and characterized CENH3 variants in genus Oryza. Our results indicated that the majority CENH3 alleles present in the Oryza gene pool carry synonymous substitutions. A few non-synonymous substitutions occur in the N-terminal Tail domain (NTT). SNP A/G at position 69 was found in accessions of AA genome and non-AA genome species. Phylogenetic analysis revealed that non-synonymous substitutions carrying alleles follow pre-determined evolutionary patterns. O. longistaminata accessions carry SNPs in four codons along with indels in introns 3 and 6. Fifteen haplotypes were mined from our panel; representative mutant alleles exhibited structural variations upon modeling. Structural analysis indicated that more than one structural variant may be exhibited by different accessions of single species (Oryza barthii). NTT allelic mutants, though not directly implicated in HI, may show variable interactions. HI and interactive behavior could be ascertained in future investigations.

Assessment of genetic diversity among wild rose in Morocco using ISSR and DAMD markers

BackgroundMorocco is considered one of the main biodiversity hotspots in the Mediterranean region and contains various plant species including wild and domestic Rosa. This genus is the most important among cultivated ornamental plants in the world, with a high economic value in cosmetics, pharmaceutical industries, and floriculture. In the present study, genetic diversity among the collected accessions of wild Rosa species in Morocco was assessed using Inter-Simple Sequence Repeat (ISSR) and Directed Amplification of Minisatellites DNA (DAMD) markers. ResultsResults confirmed that both markers used have a good efficiency to assess genetic diversity in wild roses. Ten ISSR and eight DAMD primers amplified 276 and 203 loci, with an average of 27.4 and 25 polymorphic alleles per primer, respectively. The polymorphic information content (PIC) values were 0.34 with ISSR and 0.31 with DAMD. Analysis of molecular variance (AMOVA) showed that genetic variation in wild rose occurs mainly within populations (86%) rather than between populations (14%). The region of Azrou (Middle Atlas of Morocco) is the area that registered the highest genetic diversity in the present study with He = 0.21. The 39 rose accessions were divided into three main groups with among-group similarity of 30%. Principal component analysis and the hierarchical classification were consistent with genetic relationships derived by structure analysis. ConclusionThe findings revealed that the patterns of grouping are weakly correlated with geographical origin. ISSR and DAMD markers showed that the accessions have a good genetic diversity.

Divergência genética entre acessos silvestres e híbridos de tomateiro baseada em caracteres morfoagronômicos e fisiológicos

ABSTRACT The objective of this study was to evaluate the genetic divergence among accessions of wild tomato species and interspecific F1 hybrids. Six wild accessions were characterized (Solanum pimpinellifolium ‘AF 26970’, S. galapagense ‘LA-1401’, S. peruvianum ‘AF 19684’, S. habrochaites var. hirsutum ‘PI-127826’, S. habrochaites var. glabratum ‘PI-134417’, and S. pennellii ‘LA-716’), the commercial cultivar Redenção, and the respective interspecific F1 hybrids: ‘Redenção’ x ‘AF 26970’, ‘Redenção’ x ‘LA-1401’, ‘Redenção’ x ‘AF 19684’, ‘Redenção’ x ‘PI-127826’, ‘Redenção’ x ‘PI-134417’, and ‘Redenção’ x ‘LA-716’. Thirty-five quantitative traits were evaluated, encompassing 29 morphoagronomic and six physiological characteristics. Principal component analysis (PCA) was performed. Tocher’s optimization method was used based on the Mahalanobis distance and the graphic dispersion of canonical variables, which followed the same trend of genotype clustering, forming three distinct groups. The PCA indicated some genetic divergences not shown by the other methods. A high divergence was observed among the species accessions and interspecific hybrids. The cultivar Redenção had the greatest genetic dissimilarity, and the interspecific hybrids of S. lycopersicum with wild accessions showed the greatest morphoagronomic and physiological similarity with the wild parents.

Adaptive responses to flooding in wild rice species with various genomes other than AA

ABSTRACT In the present study, 15 accessions of wild rice species belonging to genome groups different from that of Oryza sativa were tested for their adaptive response to flooding at the seedling and mature stages. Under complete submergence at the seedling stage, reduced underwater shoot elongation and high survival rate after the recovery period were observed in the accessions of O. minuta as well as tetraploid O. punctata, O. eichingeri, O. officinalis, O. alta, O. grandiglumis, O. latifolia, and O. australiensis. This suggests that these species exhibit submergence tolerance at the seedling stage. During gradual submergence at mature stage, promoted internodal elongation was observed in the accessions of diploid and tetraploid O. punctata, O. alta, O. grandiglumis, O. latifolia, and O. brachyantha. This suggests that these species possess floating ability. Remarkably, two CCDD genome species, namely O. grandiglumis and O. latifolia, strongly displayed both submergence tolerance at the seedling stage and floating ability at mature stage, suggesting that these species are valuable genetic resources for improving rice adaptability to flooding. SUB1A and SNORKEL genes are known to confer submergence tolerance and floating ability to O. sativa, respectively. However, SUB1A, SNORKEL1, and SNORKEL2 genes were not detected in any of the wild rice accessions investigated in the present study. Our results suggest that adaptive responses to flooding in the investigated wild rice species can be achieved independently of the presence or absence of SUB1A and SNORKEL genes.

Global demand for rice genetic resources

BackgroundThe International Rice Research Institute (IRRI) holds in trust the world's largest collection of rice diversity, with more than 130,000 accessions of cultivated rice and wild species. Between 2012 and 2018, a total of 2174 requests for rice germplasm were received from more than 1000 unique requestors. We documented and analyzed how genebank users made use of germplasm from IRRI. As we address food and nutrition security challenges in a changing context, we are motivated by the need to enhance the conservation, management, and use of rice genetic resources.MethodsWe examined the patterns of use of the IRRI genebank using distribution data and analyzed the results from a survey of germplasm recipients. The 2019 IRRI genebank user survey is the most recent attempt to obtain structured feedback from genebank end-users in multiple countries on their use of rice germplasm since 1995. We received 244 responses (a 35% response rate) out of the complete list of 694 respondents with valid email addresses. We also tested the relationship between the availability of germplasm information, proxied by the passport data completeness index (PDCI), and the demand for rice accessions, measured by the number of requests for each unique accession using a Negative Binomial regression model. We hypothesized that materials that are better documented are more frequently requested by users because they offer more useful information for targeted research and breeding.ResultsBetween 2012 and 2018, requests for germplasm from outside IRRI were received from 63 countries in all regions of the world, mostly from Asia. IRRI distributed germplasm externally to requestors from universities (32%), national research programs (14%), private companies (9%), and individuals, including farmers (24%) as well as other CGIAR centers (3%). The traits sought most often were tolerances to environmental stresses, followed by tolerance or resistance to biotic stresses. The majority of survey respondents confirmed the usefulness of IRRI germplasm for research, breeding, characterization, and evaluation. The analytical model confirmed the significant positive relationship between PDCI values and the demand for those accessions. The results indicated that improving the availability of information at the accession level will enhance the use of those materials. To the best of our knowledge, this study is the first to show the empirical link between documentation and use of germplasm.ConclusionsThe findings demonstrate the crucial role of IRRI's genebank as a key germplasm source for global rice research and development, with important implications for the conservation and use of rice genetic diversity in the future. Public sector organizations and the scientific community in general benefit from the conservation and availability of rice genetic resources. We also show the importance of the availability of data on conserved accession to enhance their use. To sustain the benefits, continuous investment in genebanks is needed to allow them to adapt to changes in technology and agricultural context.

Kök Lezyon Nematodlarının (Pratylenchus thornei (Sher et Allen) Pratylenchus neglectus (Rensch) Filipjev & Schuurmans Stekhoven (Tylenchida: Pratylenchidae) ve Soğan-sak Nematodu Ditylenchus dipsaci (Kühn, 1857) (Tyleneida) 'nın Nohut Yetiştirme Alanlarında Dikey Dağılımı

Investigation of the vertical distribution of three plant-parasitic nematodes was conducted in two southeastern (Şanlıurfa) and central Anatolia (Ankara) Turkey chickpea fields during 2015/2016 and 2016/2017 growing season. Twelve accessions of wild Cicer species representing three Cicer species (Cicer reticulatum L. and C. echinospermum L.) were used in the experiments for it. Soil samples were collected around the plant roots at a 10-20 cm and 20-30 cm depth by using an auger at each site. Maximum population densities of the root-lesion nematodes (Pratylenchus thornei (Sher et Allen) and (Pratylenchus neglectus (Rensch) Filipjev & Schuurmans) were observed at the depth of 20-30 cm, pod filling stage, and harvest time on most sampling. Also, the population density of root-lesion nematodes at the depths of 20-30 cm was observed as higher than Ditylenchus dipsaci (Kühn, 1857) (Tylenchida: Anguinidae) in the chickpea field. Population density of root-lesion nematodes was positively correlated with the contents of depth, site, time sampling, species chickpea, and there was determined significant difference between soil depth and population density of nematodes in both sites statistically.

Reaping the Potential of Wild Cajanus Species through Pre-Breeding for Improving Resistance to Pod Borer, Helicoverpa armigera, in Cultivated Pigeonpea (Cajanus cajan (L.) Millsp.).

Simple SummaryPigeonpea is an important legume crop that is severely affected by various insect pests, especially pod borer. Because there are low resistance levels to pod borers in the cultivated pigeonpea gene pool, it is necessary to introduce resistance-related traits from its wild relatives. In this study, we conducted a series of crosses to introduce traits related to pod borer resistance from two wild relatives of pigeonpea into two popular cultivated varieties. We generated populations from four different crosses and screened these populations for traits related to pod borer resistance: i.e., low levels of insect damage, high concentrations of insect-deterring compounds in the seeds, and the presence of trichomes on the leaves. The most promising lines were tested across seasons and locations. Ultimately, we identified 21 lines with excellent traits related to pod borer resistance. These lines will be useful for breeding new insect-resistant pigeonpea cultivars. The availability of such cultivars will reduce the use of pesticides to control pests on pigeonpea crop.Pod borer (Helicoverpa armigera) causes the highest yield losses in pigeonpea, followed by pod fly (Melanagromyza obtusa). High levels of resistance to pod borer are not available in the cultivated genepool. Several accessions of wild Cajanus species with strong resistance, and different resistance mechanisms (antixenosis and antibiosis) to pod borer have been identified. These accessions can be utilized to improve the pod borer resistance of cultivated pigeonpea. Using pod borer resistant Cajanus scarabaeoides and Cajanus acutifolius as pollen donors and popular pigeonpea varieties as recipients, pre-breeding populations were developed following simple- and complex-cross approaches. Preliminary evaluation of four backcross populations consisting of >2300 introgression lines (ILs) under un-sprayed field conditions resulted in identifying 156 ILs with low visual damage rating scores (5.0–6.0) and low pod borer damage (<50%). Precise re-screening of these ILs over different locations and years resulted in the identification of 21 ILs having improved resistance to pod borer. Because these ILs were derived from wild Cajanus species, they may contain different alleles for different resistance components to pod borer. Hence, these ILs are ready-to-use novel and diverse sources of pod borer resistance that can be utilized for improving the pod borer resistance of cultivated pigeonpea.

Breeding accession value of potato genetic resources as sources of resistance to fungal diseases

Aim. To select sources and donors of resistance to fungal diseases late blight and fusarium (Phytophthora infestans (Mont.) de Bary and Fusarium sambucinum Fuck) among the gene pool accessions and available potato forms. Results and Discussion. Among wild species accessions, sources of resistance both to late blight of tubers and to Fusarium dry rot were identified. Solznum vernei, S.ocadae, S.dodsii, S.venturii, and S.boliviense accessions had tubers with high resistance to P.infestans. In addition, 31 accessions of wild species with high resistance to F.sambucinum were identified. Among newly created backcrosses of multispecies hybrids, 31 accessions were distinguished due to high or very high resistance of tubers to the pathogen. Backcrosses G13.45s14, G14.4s11, G15.7s105, G15.10s14, G15.24s17, G15.31s3, G15.32s50, G15.32s54, G15.15.36, 38s14, G17.16s8, G17.17s12, G17.17s13, G17.19s2, G17.22s50, and G17.28s8 were noticeable for the highest resistance. Six backcrosses of multispecies hybrids with high resistance of leaves to P.infestans were obtained. ccessions of the collection of potato genetic resources stored at the Institute of Potato Growing of NAAS of Ukraine are donors of resistance to Phytophthora infestans (Mont.) de Bary: 04.20s116 (UM0101669), 86.685s56 (UM0101705), 88.1425s1 (UM0101706), 88.1450s2 (UM0101595), Santarka (UM0102819), Podoliia (UM0102818), Hurman (UM0102878), Zarevo (UM010018). Sources of resistance to Fusarium sambucinum Fuck were found among backcrosses of multispecies hybrids. Backcrosses G13.49s45, G15.36s22, G17.10s1, G17.22s12, G17.22s50, and G17.28s8 were characterized by high individual resistance. Backcrosses G15.36s22, G17.10s1, G17.22s12, and G17.22s50 are of high breeding value, as they are their resistance score is 7-9 points, both to P. infestans and to F. sambucinum. Backcross G17.28s8 stood out due to its high resistance to late blight of leaves and tubers as well as to Fusarium dry rot. Conclusions. In the potato gene pool, sources of resistance to fungal diseases late blight and fusarium (Phytophthora infestans (Mont.) de Bary and Fusarium sambucinum Fuck) were identified. Both among wild species accessions and among backcrosses of multispecies hybrids, sources of potato resistance to late blight and Fusarium dry rot were found; they are valuable starting material to breed new varieties that would be highly resistant to biotic and abiotic factors.

Genetic diversity of wild stone fruit species: specific aspects of ex situ conservation

Background. One of the most important tasks faced by the scientists of Krymsk Experiment Breeding Station of VIR is the long-term preservation of the stone fruit gene pools (over 1,000 genotypes of 44 species) collected during plant explorations. It is much more difficult to preserve representatives of the wild flora than cultivars, due to their ecological specialization to specific environments and the need to create conditions for their successful development. This aspect concerns, first of all, such species as Louiseania pedunculata (Pall.) Pachom., L. ulmifolia (Franch.) Pachom., Prunus cocomilia Ten., P. brigantiaca Vill., Armeniaca sibirica (L.) Lam., Padus ssiori (F. Schmidt) C.K. Schneid., and some others.Methods. The studies were carried out in the collection plantations of the field genebank at Krymsk Experiment Breeding Station of VIR according to VIR’s guidelines. Accessions of wild stone fruit species were the objects of the studies.Results. Many years of field research into ex situ conservation of introduced wild species proved the efficiency of stone fruit cultivation in tub culture and a modified technique of dense planting with crown formation according to the “border-hedge” pattern. It takes into account biological characteristics of genotypes shaped in natural areas, the use of own-root or grafted plants on clonal rootstocks of various growth rates depending on their life form (tree or shrub), resistance to biotic and abiotic stressors, soil and terrain requirements, and the tasks posed before researchers. The recommended planting schemes (2.5–4.0 × 0.5–1.0 m) significantly reduce the area occupied by the same number of plants in conventional cultivation patterns and cut down power and labor inputs into technological practices.

Legacy genetics of Arachis cardenasii in the peanut crop shows the profound benefits of international seed exchange

The narrow genetics of most crops is a fundamental vulnerability to food security. This makes wild crop relatives a strategic resource of genetic diversity that can be used for crop improvement and adaptation to new agricultural challenges. Here, we uncover the contribution of one wild species accession, Arachis cardenasii GKP 10017, to the peanut crop (Arachis hypogaea) that was initiated by complex hybridizations in the 1960s and propagated by international seed exchange. However, until this study, the global scale of the dispersal of genetic contributions from this wild accession had been obscured by the multiple germplasm transfers, breeding cycles, and unrecorded genetic mixing between lineages that had occurred over the years. By genetic analysis and pedigree research, we identified A. cardenasii-enhanced, disease-resistant cultivars in Africa, Asia, Oceania, and the Americas. These cultivars provide widespread improved food security and environmental and economic benefits. This study emphasizes the importance of wild species and collaborative networks of international expertise for crop improvement. However, it also highlights the consequences of the implementation of a patchwork of restrictive national laws and sea changes in attitudes regarding germplasm that followed in the wake of the Convention on Biological Diversity. Today, the botanical collections and multiple seed exchanges which enable benefits such as those revealed by this study are drastically reduced. The research reported here underscores the vital importance of ready access to germplasm in ensuring long-term world food security.

Registration of GA‐BatSten1 and GA‐MagSten1, two induced allotetraploids derived from peanut wild relatives with superior resistance to leaf spots, rust, and root‐knot nematode

AbstractWild relatives of peanut harbor alleles that confer strong resistance to diseases and pests and adaptation to environmental stresses, traits that frequently cannot be found in Arachis hypogaea. However, most wild species are diploid, while cultivated peanut (A. hypogaea L.) is tetraploid. When crossed, they produce sterile progeny, thus hindering their direct use in peanut breeding. To make the alleles of three wild species accessions directly available for breeding, we developed at the University of Georgia two fertile artificially induced allotetraploids (also known as amphidiploids or neotetraploids): GA‐BatSten1 (Reg. no. GP‐239, PI 695418) and GA‐MagSten1 (GP‐240, PI 695417). They derive from crosses between wild diploid species of peanut, A. batizocoi × A. stenosperma, and A. magna × A. stenosperma, respectively. Cuttings from the sterile diploid F1s were treated with colchicine. From some of these cuttings, fertile induced tetraploid seed were produced. These induced tetraploids are compatible with cultivated peanut, carry resistance to early and late leaf spot and root‐knot nematode, and are being used in breeding programs in the United States for the production of resistant cultivars.

Development of a genome-wide InDel marker set for allele discrimination between rice (Oryza sativa) and the other seven AA-genome Oryza species

Wild relatives of rice in the genus Oryza (composed of 24 species with 11 different genome types) have been significantly contributing to the varietal improvement of rice (Oryza sativa). More than 4000 accessions of wild rice species are available and they are regarded as a “genetic reservoir” for further rice improvement. DNA markers are essential tools in genetic analysis and breeding. To date, genome-wide marker sets for wild rice species have not been well established and this is one of the major difficulties for the efficient use of wild germplasm. Here, we developed 541 genome-wide InDel markers for the discrimination of alleles between the cultivated species O. sativa and the other seven AA-genome species by positional multiple sequence alignments among five AA-genome species with four rice varieties. The newly developed markers were tested by PCR-agarose gel analysis of 24 accessions from eight AA genome species (three accessions per species) along with two representative cultivars (O. sativa subsp. indica cv. IR24 and subsp. japonica cv. Nipponbare). Marker polymorphism was validated for 475 markers. The number of polymorphic markers between IR24 and each species (three accessions) ranged from 338 (versus O. rufipogon) to 416 (versus O. longistaminata) and the values in comparison with Nipponbare ranged from 179 (versus O. glaberrima) to 323 (versus O. glumaepatula). These marker sets will be useful for genetic studies and use of the AA-genome wild rice species.

Resistance to Bemisia tabaci in tomato species and hybrids and its association with leaf trichomes

Chemical insecticides comprise the most widely used method of tomato pest control. Genotypes resistant to pests such as the silver leaf whitefly Bemisia tabaci may contribute towards the decreased use of insecticides to protect the environment. Leaf trichomes play a role in imparting resistance to pests, and exploiting intraspecific and interspecific variability for leaf trichomes in the tomato gene pool is an alternative to speed up introgression of resistance into improved lines or cultivars. We assessed the levels of whitefly resistance and trichome morphology/density in an array of accessions of the tomato gene pool and their hybrids with a tomato cultivar. A commercial cultivar (S. lycopersicum cv. Redencao), six wild species accessions, two S. lycopersicum var. cerasiforme genotypes, and eight intra and interspecific F1 hybrids were tested. The accessions LA 1401 (S. galapagense), AF 19684 (S. peruvianum), PI 127826 (S. habrochaites var. hirsutum), PI 134417 (S. habrochaites var. glabratum), LA 716 (S. pennellii), and RVTC 03 (S. lycopersicum var. cerasiforme) genotypes showed a higher density of glandular trichomes and carried the highest levels of whitefly resistance than the commercial cultivar. Segregating generations from their crosses with the cultivar may be promising sources to select plants with both higher density of glandular trichomes and resistance to whiteflies. Populations derived from S. lycopersicum var. cerasiforme’ RVTC 03’, which is part of intraspecific S. lycopersicum variability, maybe a more convenient source of pest resistance than those derived from interspecific crosses to obtain pest-resistant tomato cultivars.

Genetic Resources of Genus Allium in India: Collection Status, Distribution and Diversity Mapping using GIS Tools

The genetic resources of cultivated and wild Allium species collected from different states of the country have been discussed and analysed for distribution, diversity status and gaps. A total of 5,004 germplasm accessions have been collected during 1976-2020 by ICAR-NBPGR in collaboration with National Agricultural Research System (NARS) consisting 4,924 accessions of cultivated and 80 accessions of wild Allium species. Out of 5,004 accessions, 2,708 accessions have been conserved in National Genebank at ICAR-NBPGR, New Delhi. The cultivated alliums consist of 11 species, out of which nine species have been conserved (2,641 accessions). The wild Allium species comprise of 13 species out of which 11 species have been conserved (67 accessions). This study identified Western Himalaya as rich areas of diversity (H=1.491-2.0) for wild Allium species. Analysis indicated a significant gap for 21 wild taxa which are neither collected nor conserved in the genebank. Future thrust on explorations to be executed for collection of germplasm of these Allium species is discussed in this paper.

Wild Lathyrus species as a great source of resistance for introgression into cultivated grass pea (Lathyrus sativus L.) against broomrape weeds (Orobanche crenata Forsk. and Orobanche foetida Poir.)

AbstractBroomrape weeds (Orobanche spp.) are root holoparasitic plants that cause serious damage to a range of legume crops in the Mediterranean and sub‐Saharan African regions. Grain yield of cultivated species of grass pea (Lathyrus sativus L.) is almost negligible at the highest infection severity of Orobanche. Crop wild relatives (CWRs) have emerged as a novel source for many traits in diverse crops. Lathyrus is one of the largest genera with more than 160 species. In the present study, we screened 285 accessions representing 13 Lathyrus species for their reactions against two common broomrape species, Orobanche crenata Forsk. and O. foetida Poir, under field conditions. Screening at hot spots in Morocco and Tunisia resulted in the identification of resistant accessions of wild Lathyrus species against the parasitic weed. The level of resistance to O. foetida was higher among wild species compared with O. crenata. Field results showed complete resistance for O. crenata and O. foetida by L. articulatus L. and moderate resistance by L. aphaca L. and L. ochrus (L.) DC. Resistance to O. crenata in L. sativus accessions was validated in a pot experiment under controlled conditions. Two accessions—namely, IG64782 and IG65197—showed complete resistance to O. crenata. A moderately resistant accession, IG116989, that revealed low infestation in the field showed high susceptibility in pot experiment. The results indicated that the resistance against O. crenata and O. foetida was associated with slow development of the established tubercles and low induction of parasite germination.

Deciphering S-RNase Allele Patterns in Cultivated and Wild Accessions of Italian Pear Germplasm

The genus Pyrus is characterized by an S-RNase-based gametophytic self-incompatibility (GSI) system, a mechanism that promotes outbreeding and prevents self-fertilization. While the S-genotype of the most widely known pear cultivars was already described, little is known on the S-allele variability within local accessions. The study was conducted on 86 accessions encompassing most of the local Sicilian varieties selected for their traits of agronomic interest and complemented with some accessions of related wild species (P. pyrifolia Nakai, P. amygdaliformis Vill.) and some national and international cultivars used as references. The employment of consensus and specific primers enabled the detection of 24 S-alleles combined in 48 S-genotypes. Results shed light on the distribution of the S-alleles among accessions, with wild species and international cultivars characterized by a high diversity and local accessions showing a more heterogeneous distribution of the S-alleles, likely reflecting a more complex history of hybridization. The S-allele distribution was largely in agreement with the genetic structure of the studied collection. In particular, the “wild” genetic background was often characterized by the same S-alleles detected in P. pyrifolia and P. amygdaliformis. The analysis of the S-allele distribution provided novel insight into the contribution of the wild and international cultivars to the genetic background of the local Sicilian or national accessions. Furthermore, these results provide information that can be readily employed by breeders for the set-up of novel mating schemes.