Use made of wild legume relatives in breeding

Presently vast genetic resources are available for improvement of the main crops used by humans and animals. The ex-situ collections safeguard those resources collected in the past, although not all collections are safe even today as far as personnel and facilities are concerned. Use of in-situ collections is feasible but meeting with obstacles. Free accessibility is not as straightforward as has been in the past. Apart from the cultivated accessions of crops, wild relatives have always attracted breeders, for these contribute many useful traits. Their genetic background, particularly of species in the secondary or tertiary genepool, makes transfer difficult requiring new techniques to effectuate gene transfers. There have been many attempts and evaluation and conservation of wild relatives is usually a task taken up by most genebanks. Genetic modification, the modern way of transferring wanted genes, has barely begun for the legume food crops. This paper presents some examples of successful use made of wild relatives of chickpea, pigeonpea, fababean and lentil for breeding during the past decenni

Exploiting genomic resources for efficient conservation and utilization of chickpea, groundnut, and pigeonpea collections for crop improvement

Both chickpea and pigeonpea are important dietary source of protein, while groundnut is one of the major oil crops. Globally, ~1.1 million grain legume accessions are conserved in genebanks, of which, ICRISAT genebank holds ~50,000 accessions of cultivated species and wild relatives of chickpea, pigeonpea, and groundnut from 133 countries. These genetic resources are reservoirs of many useful genes for the present and future crop improvement programs. Representative subsets in the form of core and mini core collections have been used to identify trait-specific genetically diverse germplasm for use in breeding and genomic studies in these crops. Chickpea, groundnut and pigeonpea have moved from ‘orphan’ to ‘genomic resources rich crops’. The chickpea and pigeonpea genomes have been decoded, and the sequences of groundnut genome will soon be available. With the availability of these genomic resources, the germplasm curators, breeders and molecular biologists will have abundant opportunities to enhance the efficiency of genebank operations, mine allelic variations in germplasm collection, identify genetically diverse germplasm with beneficial traits, broaden the cultigen’s genepool, and accelerate the cultivar development to address new challenges to production, particularly with respect to climate change and variability. Marker-assisted breeding approaches have already been initiated for some traits in chickpea and groundnut, which should lead to enhanced efficiency and efficacy of crop improvement. Resistance to some pests and diseases has been successfully transferred from wild relatives to cultivated species

Construction of a genetic linkage map and QTL analysis for late leaf spot and rust in groundnut (Arachis hypogaea L.)

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Using genetic and genomic resources to broaden the genetic base of cultivated groundnut

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Genetic enhancement of resistance to foliar diseases - strategies and prospects

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Multiple resistant and nutritionally dense germplasm identified from mini core collection in peanut

Peanut (Arachis hypogaea L.) is extensively grown by resource-poor farmers in the semiarid tropics where many abiotic and biotic stresses limit the crop's productivity and seed quality. Peanut cultivars with enhanced host-plant resistance, adaptation to abiotic stress, input-use efficiency, and yield potential will maximize yield gains and minimize inputs to sustain production. The peanut mini core collection was evaluated for agronomic traits in multienvironment trials at Patancheru, India. The published information on 184 mini core accessions revealed 28 accessions resistant to abiotic stress, 30 resistant to biotic stress, and 18 that were agronomically desirable but susceptible to stresses, while 16 were seed nutrient dense. The mini core is part of the composite collection, which was previously genotyped using SSRs. The agronomic evaluation, stress response, and nutritional information together with genotyping data were used to identify genetically diverse germplasm with agronomically beneficial traits: ICG 12625 (resistance to drought, low temperature, late leaf spot [LLS], Aspergillus flavus Link, bacterial wilt; high oil and good oil quality) and ICG 442 (resistance to drought, salinity, P deficiency); ICG 12625 and ICG 2381 (resistance to rust, A. flavus; good oil quality); ICG 12697 (resistance to LLS, rust, A. flavus) and ICG 6022 (resistance to early leaf spot [ELS], LLS); ICG 14710 (high oil, Fe, Zn) and ICG 7963 (high protein, Fe, Zn); ICG 11426 (resistance to ELS, LLS, rust) and ICG 5221 (high Fe and Zn and good oil quality). Accessions with adaptation to rainy and/or post-rainy environments were ICG# 434, 5745, 8285, 10036, 11088, 11651, 12625, 15042, and 15419. These accessions are ideal genetic resources that may be used to develop agronomically superior and nutritionally enhanced peanut cultivars with multiple resistances to abiotic and biotic stresses

Genetic structure, diversity, and allelic richness in composite collection and reference set in chickpea (Cicer arietinum L.)

Background Plant genetic resources (PGR) are the basic raw materials for future genetic progress and an insurance against unforeseen threats to agricultural production. An extensive characterization of PGR provides an opportunity to dissect structure, mine allelic variations, and identify diverse accessions for crop improvement. The Generation Challenge Program http://www.generationcp.org conceptualized the development of "composite collections" and extraction of "reference sets" from these for more efficient tapping of global crop-related genetic resources. In this study, we report the genetic structure, diversity and allelic richness in a composite collection of chickpea using SSR markers, and formation of a reference set of 300 accessions. Results The 48 SSR markers detected 1683 alleles in 2915 accessions, of which, 935 were considered rare, 720 common and 28 most frequent. The alleles per locus ranged from 14 to 67, averaged 35, and the polymorphic information content was from 0.467 to 0.974, averaged 0.854. Marker polymorphism varied between groups of accessions in the composite collection and reference set. A number of group-specific alleles were detected: 104 in Kabuli, 297 in desi, and 69 in wild Cicer; 114 each in Mediterranean and West Asia (WA), 117 in South and South East Asia (SSEA), and 10 in African region accessions. Desi and kabuli shared 436 alleles, while wild Cicer shared 17 and 16 alleles with desi and kabuli, respectively. The accessions from SSEA and WA shared 74 alleles, while those from Mediterranean 38 and 33 alleles with WA and SSEA, respectively. Desi chickpea contained a higher proportion of rare alleles (53%) than kabuli (46%), while wild Cicer accessions were devoid of rare alleles. A genotype-based reference set captured 1315 (78%) of the 1683 composite collection alleles of which 463 were rare, 826 common, and 26 the most frequent alleles. The neighbour-joining tree diagram of this reference set represents diversity from all directions of the tree diagram of the composite collection. Conclusion The genotype-based reference set, reported here, is an ideal set of germplasm for allele mining, association genetics, mapping and cloning gene(s), and in applied breeding for the development of broad-based elite breeding lines/cultivars with superior yield and enhanced adaptation to diverse environments

Tapping the large genetic variability for salinity tolerance in chickpea

Salinity is an ever-increasing problem in agriculture worldwide and especially in Australia. Improved genotypes that are well adapted to saline conditions are needed to enhance and sustain production in these areas. A screening of 263 accessions of chickpea, including 211 accessions from ICRISAT’s mini-core collection (10% of the core collection and 1% of the entire collection), showed a six-fold range of variation for seed yield under salinity, with several genotypes yielding 20% more than the previously-released salinity tolerant cultivar CSG8962. No significant relation was found between biomass at the late vegetative stage and final seed yield under salinity. Performance of seed yield under salinity was explained in part by the yield potential under control conditions, and a salinity tolerance component. The major trait related to salinity tolerance was the ability to maintain under salinity a large number of viable pods with seeds. In contrast, the relative seed size under salinity did not differ between tolerant and sensitive genotypes. Preliminary analysis of genotypic data for approximately 50 SSR markers on 211 genotypes revealed some associations with salinity tolerance that deserve a detailed analysis. Future effort should focus on the effect of salinity on the reproductive stage of development

Genetic resources conservation and strategies for enhanced utilization in crop improvement

Global food production will need to double to feed the more than 9 billion people by 2050..