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

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Not AvailableA mini-core collection consists of a limited set of accessions derived from an existing collection, chosen to represent the genetic spectrum in the collection, and provides the user a set of genetically and ecologically distinct accessions. The evaluation of 210 mini-core germplasm accessions revealed considerable variation among accessions for all the traits studied. This collection was evaluated for nine qualitative characters. In Asia, India accounted for 83 accessions (39.5%) in the mini-core collection followed by Iran 53 accessions (25.2%). Ethiopia, which is the secondary centre of diversity for chickpea, accounted for only 14 (6.6%) accessions in the mini-core collection. In this study most of the germplasm were semi-spreading type, pink flower, medium seed size, brown seed colour, rough seed surface and desi type of seed shape. These accessions were found promising for qualitative traits will be utilized in chickpea quality improvement.IARI, New Delh

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Not AvailableThirty one uniform and stable germplasm accessions of economic importance of sunflower were crossed with five cytoplasmic male sterile lines viz., CMS-234A, CMS-17A, CMS-338A, CMS-851A and ARM-243A in a Line x Tester fashion to study their maintainer or restorer reaction during kharif-2012 in a randomized block design in two replications. The accessions TSG-22, TSG-24, ID-7, SCG-37, RHA-464 and ID-25 acted as restores for all five CMS lines. It was found that ID-33 of the restorer for ARM-243A was maintainer for other CMS lines. The use of stable germplasm with restorer behaviour in heterosis breeding programmes and those with maintainer behaviour in the development of new CMS lines through conversion has been suggested. The identification of new restorers to the good combiner CMS sources assembled should receive priority for hybrid synthesis.Not Availabl

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Not AvailableSunflower (Helianthus annuus L.) is one of the world’s most important oilseed crops with a multitude of uses. Genetic base of this crop as revealed by the pedigree records of released cultivars appears to be narrow because of the frequent use of the same parents and their derivatives in heterosis breeding programmes. Pedigree analysis of 30 sunflower hybrids that have been released from 1980 to 2020 by public sector through hybridization in the country traced back to a few ancestors and thereby increasing the genetic vulnerability to biotic (diseases and insect pests) and abiotic (drought, salinity, heat) stresses. This appears to be insignificant part of the germplasm accessions conserved in Indian gene bank. Rate of infusion of new germplasm in sunflower breeding programmes has also been slow due to repeated use of the same germplasm for development of cultivars. This shows that a vast majority of accessions held in gene bank have made limited contribution in development of modern cultivars. In sunflower, 30% hybrids developed through hybridization have CMS-234A as female parent in their pedigree. Ancestors, RHA-95C-1 and CMS-17A appeared in 13% and 10% hybrids, respectively. Similarly, RHA-1-1, P-93R and RHA-6D-1 appeared in 7%, 7% and 10% cultivars, respectively. Only 6 parents (2 CMS & 4 R lines) could represent 33% of total genetic base of sunflower cultivars developed in the country.This analysis revealed that genetic base of sunflower hybrids is narrow and needs immediate corrective measures by involving trait specific germplasm accessions, exotic and wild relatives in breeding programmes for broadening the genetic base of cultivars. With the advent of modern breeding tools and techniques including various molecular biology tools it has become possible to incorporate genes from various divergent sources systematically in less time and with less financial resources for yield improvement and stabilization. The utilization of wild Helianthus species will lead to broadening of genetic base thus increasing crop resilience towards various biotic and abiotic stresses.ICA

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Not AvailableSunflower (Helianthus annuus L.) is one of the important oilseed crops cultivated worldwide for its oil and confectionary purposes. Among the crops where heterosis has been successfully exploited, sunflower assumes importance as that of maize. Identification of the PET-1 cytoplasm along with the complementary fertility restoration system is a landmark achievement which paved the way for transformation of an ornamental crop to a commercial oil yielding crop. Breeding objectives are directed towards development of cultivars with high seed yield, early maturity, resistance to diseases (downy mildew, powdery mildew, rust, necrosis disease, Alternariaster leaf spot), insect pests (Helicoverpa, sucking pests) and tolerance to herbicides, besides improved content and quality of seed oil and protein. Genetic enhancement for widening the trait base exploited traditional breeding methods, mutation breeding and interspecific gene transfer. Interspecific hybridization was adopted as one of the key tools by various research groups due to the existence of a rich repertoire of genes in the wild Helianthus species, and several economically important traits such as cytoplas mic male sterility, resistance to biotic and abiotic stresses, herbicide tolerance and seed quality traits were successfully introgressed. The past two decades witnessed advancements in molecular marker technology and genomics which have been successfully used in marker-assisted breeding for simple inherited traits, while traits governed by quantitative trait loci still remain a challenge for the breeders. Despite the availability of genes in wild Helianthus species, successful transfer to cultivar germplasm is hampered by crossability between cultivated sunflower (annual diploid) and Helianthus species varying in habit (diploid perennial) and ploidy (tetraploids, hexaploids) warranting the use of genetic engineering approaches. This chapter presents a comprehensive account of the history, bot any, the extent of genetic diversity in cultivated and wild Helianthus species. Strategies are adopted for development of inbreds and hybrids, seed production methodology and progress with regard to exploitation of molecular marker and genomic resources in marker-assisted breeding.Not Availabl

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Not AvailableThirty one uniform and stable germplasm accessions of economic importance of sunflower were crossed with five cytoplasmic male sterile lines viz., CMS-234A, CMS-17A, CMS-338A, CMS-851A and ARM-243A in a Line x Tester fashion to study their maintainer or restorer reaction during kharif-2012 in a randomized block design in two replications. The accessions TSG-22, TSG-24, ID-7, SCG-37, RHA-464 and ID-25 acted as restores for all five CMS lines. It was found that ID-33 of the restorer for ARM-243A was maintainer for other CMS lines. The use of stable germplasm with restorer behaviour in heterosis breeding programmes and those with maintainer behaviour in the development of new CMS lines through conversion has been suggested. The identification of new restorers to the good combiner CMS sources assembled should receive priority for hybrid synthesis.Not Availabl

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Not AvailableBiotic stresses cause significant loss in crop plants and management of biotic stresses (Diseases and pests) not only increases the cost of production but also has implications on environment and ecology. Increasing use of chemical agents for biotic stress management is concern for growers, exporters and animal and human health. The best method is to use resistant varieties which are economical, healthier and eco-friendly approach. Breeding for disease and pest resistance is major objective in most of the breeding programs across the crop species and world. The resistance breeding requires the resistant source or donor which may be the same species, related species of same genera or family, or altogether an alien species. There is need of recipient or target species and method of transfer of resistance. There are different approaches for breeding for resistance against different kinds of stress which involve both conventional and modern tools. Resistance breeding approach is to be at least one step ahead of the pathogen or pest in question. Achieving the goal of development of a resistant variety also needs attention on the durability of resistance for which the knowledge of resistance on the inheritance, expression and interaction with fellow genes and environment aspects. In this chapter emphasis has been given on importance of biotic stresses, inheritance, resistance sources, breeding approaches, and modern tools.Not Availabl

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Not AvailableThis study was conducted to evaluate the effect of drought stress on 22 chickpea genotypes and one check by analyzing ecophysiological traits in field condition. Field experiments were carried out during 2009-2010 in two separate irrigated and non-irrigated conditions with randomized complete block design in three replications. Yield and yield components (RWC) were measured in each experiment, separately. Drought resistance indices of Relative water contour (RWC) and member stability index (MSI) were recorded under rainfed condition. Results indicated that values of studied traits significantly decreased in non-irrigated experiment compared to irrigated one. Correlation analysis revealed that grain yield/plant had significant genotypic and highly significant phenotypic relationship with number of pods/plant, number of seeds/pod, harvest index and biological yield/plant. Therefore, it is suggested that these traits should be used as selection criteria for yield improvement in chickpea.Not Availabl

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Not AvailableHeterosis breeding has been commercially exploited in sunflower and is expected to enhance productivity further. This is the only crop which has more than 80% sunflower growing area under the hybrids. The first hybrid (BSH-1) of sunflower from public sector was released for commercial cultivation in 1980. Since then the hybrid breeding program has been quite successful and 29 productive hybrids were developed by both public (18) and private sectors (11). Inspite of these successes, problems in the form of stagnating and unstable yields, genetic vulnerability and susceptibility to various diseases are threatening sunflower productivity in India. One of the major challenges would be to develop newer hybrids for diverse situation and superior to those presently grown in terms of seed and oil yield in order to sustain the competitive ability of sunflower vis-avis other crops. There is a need for new CMS lines with diverse cytoplasm having several desirable attributes like dwarfness and early maturity. The diverse CMS lines are expected to contribute towards the development of superior hybrids producing high seed yield and oil content with better heterosis and stability. The CMS base exploited in the sunflower breeding programmes is narrow and there is an urgent need for widening the CMS and restorer (R) line base for enhancing the productivity and production of sunflower.Not Availabl