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Finger millet [Eleusine coracana (L.) Gaertn] is an important crop used for food, fodder and industrial purposes. With the objective of increasing the utilization of finger millet germplasm in crop improvement, A composite collection consisting of 1000 accessions was developed and genotypically and profiled using 20 SSR markers. This study reported the genetic diversity and development of genotype based reference set with most diverse 300 accessions. Allelic data on 959 accessions and 20 markers based on quality index was used for further statistical analysis. A total of 231 (121 common and 110 rare) alleles were detected in the composite collection. Gene diversity varied from 0.200 to 0.850. The average frequency of multiple alleles were maximum (13.6%) in race spontanea wild types and ranged from 1.7 to 9.5% in other races. A reference set consisting 300 genetically most diverse accessions was established. This reference set had 206 (89.2%) of the 231 alleles detected in the composite collection, and showed high gene diversity (0.307 to 0.852).

Modern agriculture faces challenges, such as loss of soil fertility, fluctuating climatic factors and increasing pathogen and pest attacks. Sustainability and environmental safety of agricultural production relies on eco-friendly approaches like biofertilizers, biopesticides and crop residue return. The multiplicity of beneficial effects of microbial inoculants, particularly plant growth promoters (PGP), emphasizes the need for further strengthening the research and their use in modern agriculture. PGP inhabit the rhizosphere for nutrients from plant root exudates. By reaction, they help in (1) increased plant growth through soil nutrient enrichment by nitrogen fixation, phosphate solubilization, siderophore production and phytohormones production (2) increased plant protection by influencing cellulase, protease, lipase and β-1,3 glucanase productions and enhance plant defense by triggering induced systemic resistance through lipopolysaccharides, flagella, homoserine lactones, acetoin and butanediol against pests and pathogens. In addition, the PGP microbes contain useful variation for tolerating abiotic stresses like extremes of temperature, pH, salinity and drought; heavy metal and pesticide pollution. Seeking such tolerant PGP microbes is expected to offer enhanced plant growth and yield even under a combination of stresses. This review summarizes the PGP related research and its benefits, and highlights the benefits of PGP rhizobia belonging to the family Rhizobiaceae, Phyllobacteriaceae and Bradyrhizobiaceae.

Chickpea (Cicer arietinum L.) is a major grain legume crop in South Asia, and terminal drought severely constrains its productivity. In this review, we describe how root systems can improve the productivity of chickpea under the terminal drought that occurs in a receding stored soil water conditions in central and south India and propose possible breeding and screening methods. In chickpea, total root biomass in early growth stages has been shown to significantly contribute to seed yield under terminal drought in central and south India. Maximising acquisition of water stored in 15–30 cm soil layer by roots had greater implications as the timing of absorption, available soil water and root size matches well for the complete use of water from this zone. However, deeper root systems and a greater exploitation of subsoil water offers potential for further productivity improvements under terminal drought. As proof of this concept, contrasting chickpea accessions for important root traits, such as root biomass and rooting depth, have been screened in a chickpea germplasm collection which comprises rich diversity for root traits. Through analysing mapping populations derived from crosses between these accessions, a ‘QTL hotspot’ that explained a large part of the phenotypic variation for the major drought tolerance traits including root traits was identified and introgressed into a leading Indian chickpea cultivar. Yield advantages of the introgression lines were demonstrated in multi-location evaluations under terminal drought. As an alternative screening method, that would indirectly asses the root system strength, to identify further promising chickpea genotypes with multiple drought tolerance traits, the leaf canopy temperature and carbon isotope discrimination measurements can be proposed.

Canopy temperature depression (CTD) has been used to estimate crop yield and drought tolerance. However, when to measure CTD for the best breeding selection efficacy has seldom been addressed. The objectives of this study were to evaluate CTD as a drought response measure, identify suitable crop stage for measurement and associated molecular markers. CTD was measured using an infrared camera on 59, 62, 69, 73, 76 and 82 days after sowing (DAS) and the grain yield, shoot biomass and harvest index (%). CTD recorded at 62 DAS was positively associated with the grain yield by 40% and shoot biomass by 27% and such association diminished gradually to minimum after 76 DAS. Moreover, CTD at 62 DAS also showed similar positive association with the grain yield recorded in two previous years (r = 0.45***, 0.42***). Genome-wide and candidate gene based association analysis had revealed the presence of nine SSR, 11 DArT and three gene-based markers that varied across the six stages of observation. Two SSR markers were associated with CTD through crop phenology or grain yield while the rest were associated only with CTD for computing marker-trait associations (MTAs). The phenotypic variation explained by the markers was the highest at 62 DAS. These results confirm the importance of continued transpiration and the ability of the roots to supply stored soil water under terminal drought. The selection for grain yield through CTD is done best 15 days after the mean flowering time.

Flowering time and crop duration are the most important traits for adaptation of chickpea (Cicer arietinum L.) to different agro-climatic conditions. Early flowering and early maturity enhance adaptation of chickpea to short season environments. This study was conducted to establish allelic relationships of the early flowering genes of ICC 16641, ICC 16644 and ICCV 96029 with three known early flowering genes, efl-1 (ICCV 2), ppd or efl-2 (ICC 5810), and efl-3 (BGD 132). In all cases, late flowering was dominant to early-flowering. The results indicated that the efl-1 gene identified from ICCV 2 was also present in ICCV 96029, which has ICCV 2 as one of the parents in its pedigree. ICC 16641 and ICC 16644 had a common early flowering gene which was not allelic to other reported early flowering genes. The new early flowering gene was designated efl-4. In most of the crosses, days to flowering was positively correlated with days to maturity, number of pods per plant, number of seeds per plant and seed yield per plant and negatively correlated or had no correlation with 100-seed weight. The double-pod trait improved grain yield per plant in the crosses where it delayed maturity. The information on allelic relationships of early flowering genes and their effects on yield and yield components will be useful in chickpea breeding for desired phenology.

Plant genetic resources are raw materials and their use in breeding is one of the most sustainable ways to conserve biodiversity. The ICRISAT has over 120,000 accessions of its five mandate crops and six small millets. The management and utilization of such large diversity are greatest challenges to germplasm curators and crop breeders. New sources of variations have been discovered using core and minicore collections developed at the ICRISAT. About 1.4 million seed samples have been distributed; some accessions with specific attributes have been requested more frequently. The advances in genomics have led researchers to dissect population structure and diversity and mine allelic variations associated with agronomically beneficial traits. Genome-wide association mapping in sorghum has revealed significant marker–trait associations for many agronomically beneficial traits. Wild relatives harbour genes for resistance to diseases and insect pests. Resistance to pod borer in chickpea and pigeonpea and resistance to rust and late leaf spot in groundnut have been successfully introgressed into a cultivated genetic background. Synthetics in groundnut are available to broaden the cultigen's gene pool. ICRISAT has notified the release of 266 varieties/cultivars, germplasm, and elite genetic stocks with unique traits, with some having a significant impact on breeding programs. Seventy-five germplasm lines have been directly released for cultivation in 39 countries.

Pilot interventions through the Tropical Legumes II (TL-II) Project have shown promise in making new varieties available to farmers who depend on the farmer seed system. These initiatives which includes community seed schemes, seed recovery and seed bank schemes, seed fairs, contracting schemes, small seed packs, etc being promoted under TL-II, are further developed, and linked to participatory research, where farmers are directly involved in variety selection and testing. R&D agencies linked through TL-II implementation are designing and testing demand-driven seed supply strategies, which provide the necessary incentives for farmers to buy seed from the marketplace. The alternative approaches described above are based on two propositions; that different approaches are required for different crops and that we must lay greater emphasis on stimulating seed demand rather than focusing exclusively on seed supply. This report describes the legume seed dissemination strategies used for chickpea in Ethiopia, and groundnut and pigeonpea in Malawi and Tanzania and other TL-II focus countries. Preliminary research results from TL-II baseline studies in all three countries found that there was very limited awareness about improved legume varieties, and that neither public- nor private-sector interventions to produce and market legume seeds had a successful track record in these countries. To overcome these constraints investments have been made in breeder and foundation seed production, and proceeds from seed sales used to re-capitalize seed revolving funds that are then used to support subsequent seed production cycles.

Pigeonpea is no more an orphan crop in Eastern and southern Africa(ESA), with its multiple benefits to cropping systems, smallholder farmers, consumers and traders. pigeonpea has huge regional and international export potential and india alone imports 506,000 t annually. ESA countries export about 200,000 t of grain per year that worth $ 180 million. During the last two decades, area and production in ESA increased dramatically by 135% and 125%, respectively. Tanzania, Malawi, Mozambique, Kenya and Uganda are the major pigeonpea producers. Tanzania and Malawi are showing the path to success in terms of productivity and production gains that guide other countries to follow. Pigeonpea improvement in ESA started in 1992 and since then 27 high yielding varieties were released and adopted them widely. The major breeding priorities were high grain yield, inter-cropping compatibility, photo-period insensitivity, grain quality, resistance/tolerance to Fusarium wilt, Helicoverpa pod borer and resilience to climate change. ESA has unique genetic diversity and its use in genetic enhancement has paid rich dividends. Tremendous yield gains have been recoreded with the use of new varieties, integated crop management, effective seed systems and sustained market demand. However, a huge gap still exists between realizable and actual yields with present technologies. ICRISAT-Patancheru is utilizing hybrid pigeonpea technology, genomic and genetic resources most effectively. Efforts are being made to use them in ESA breeding program to further elevate yield potentials in the region. A region specific strategy being outlined to bridge the gaps between actual, realized and potential yields using conventional and modern breeding by involving all the stakeholders.

Tropical Legumes II (TL-II) seeks to improve the livelihoods of 60 million smallholder farmers (SHF) in 15 countries through enhanced productivity of chickpeas, common beans, cowpeas, groundnut, pigeonpeas and soybeans. It is implemented by ICRISAT, CIAT and IITA in collaboration with NARS of Burkina Faso, Ghana, Mali, Niger, Nigeria, Senegal, Ethiopia, Kenya, Malawi, Mozambique, Tanzania, Uganda, Zimbabwe, Bangladesh and India. The project is designed to help SHF overcome constraints such as drought, pests, diseases and lack of seed of improved varieties. TL-II is expected to enhance productivity by at least 20% through increased adoption covering 30% of legume area, strengthen national breeding programs and generate at least $1.3 billion in added value as a result. Significant achievements have been made. Active breeding programs are now in place in all 15 countries. 129 new varieties have been released and are fast replacing old ruling varieties. 37 national partners were trained to MSc and PhD. More than 258,000 tons improved seed was produced between 2007-2013, enough to reach 51.6 million farmers in 5kg packs. Innovative approaches to target the poor - especially women such as small seed packs, seed loans and decentralized production schemes were promoted. Since 2007, improved varieties disseminated have been adopted on 2,007,889 ha and generated US$513 million from project funding and nearly $2 billion from project and partners investments. In effect, for each dollar invested, the project generates $11 with direct project investment or $39 with partnership's investment. These successes and associated challenges will be discussed.

In Eastern and Southern Africa(ESA), chickpea is grown on about 493,000 ha. Ethiopia and Tanzania are the major chickpea growing countries by occupying 73% of total ESA area, and minor producing countries are Malawi, Kenya, Eritrea, Sudan and Uganda. Chickpea provides a unique oppourtunity to grow in post-rainy season under residual moisture conditions. Ethiopia is the major chickpea producer and exporter in ESA and during last one decade production(119%) and productivity(78%) have increased substantially. Ethiopia and Tanzania export a sizable quantities of chickpea and earning about 46.6 million $ annually. Chickpea improvement in ESA over the years resulted in release of 40 high yielding varieties with desirable agronomic and quality traits. The major breeding priorities in ESA were high grain yield, resistance to Fusarium wilt, collar rot, dry root rot and ascochyta blight;tolerance to Helicoverpa pod borer, terminal drought and grain quality traits. The current productivity levels in Ethiopia is about 1730 kg/ha and but in all other ESA countries productivity levels are still below 1000 kg/ha. The productivity gains in Ethiopia, providing an opportunity for cross learning among neighbouring countries. The new varieties and breeding populations developed by ICRISAT using conventional and molecular breeding approaches have been evaluated in ESA and their adaptability and adoption rates are very high. However, a huge untapped yield potential exists in the currently released as well as pipe line varieties. Better integration of available genomic and genetic resources in breeding, effective seed production and delivery, integrated crop management, wider stakeholder participation will provide an oppourtunity to futher enhance on-farm yields.

Advances in next-generation sequencing and genotyping technologies have enabled generation of large-scale genomic resources such as molecular markers, transcript reads and BAC-end sequences (BESs) in chickpea, pigeonpea and groundnut, three major legume crops of the semi-arid tropics. Comprehensive transcriptome assemblies and genome sequences have either been developed or underway in these crops. Based on these resources, dense genetic maps, QTL maps as well as physical maps for these legume species have also been developed. As a result, these crops have graduated from ‘orphan’ or ‘less-studied’ crops to ‘genomic resources rich’ crops. This article summarizes the above-mentioned advances in genomics and genomics-assisted breeding applications in the form of marker-assisted selection (MAS) for hybrid purity assessment in pigeonpea; marker-assisted backcrossing (MABC) for introgressing QTL region for drought-tolerance related traits, Fusarium wilt (FW) resistance and Ascochyta blight (AB) resistance in chickpea; late leaf spot (LLS), leaf rust and nematode resistance in groundnut. We critically present the case of use of other modern breeding approaches like marker-assisted recurrent selection (MARS) and genomic selection (GS) to utilize the full potential of genomics-assisted breeding for developing superior cultivars with enhanced tolerance to various environmental stresses. In addition, this article recommends the use of advanced-backcross (AB-backcross) breeding and development of specialized populations such as multi-parents advanced generation intercross (MAGIC) for creating new variations that will help in developing superior lines with broadened genetic base. In summary, we propose the use of integrated genomics and breeding approach in these legume crops to enhance crop productivity in marginal environments ensuring food security in developing countries.

ICRISAT scientists, working with Indian programme counterparts, developed the world's first cytoplasmic-nuclear male sterility (CMS)-based commercial hybrid in a food legume, the pigeonpea [Cajanus cajan (L.) Millsp.]. The CMS, in combination with natural outcrossing of the crop, was used to develop viable hybrid breeding technology. Hybrid ICPH 2671 recorded 47% superiority for grain yield over the control variety ‘Maruti’ in multilocation on-station testing for 4 years. In the on-farm trials conducted in five Indian states, mean yield of this hybrid (1396 kg/ha) was 46.5% greater than that of the popular cv. ‘Maruti’ (953 kg/ha). Hybrid ICPH 2671 also exhibited high levels of resistance to Fusarium wilt and sterility mosaic diseases. The outstanding performance of this hybrid has led to its release for cultivation in India by both a private seed company (as ‘Pushkal’) and a public sector university (as ‘RV ICPH 2671’). Recent developments in hybrid breeding technology and high yield advantages realized in farmers' fields have given hope for a breakthrough in pigeonpea productivity.

Chickpea is an important protein-rich crop with considerable diversity present among 44 annual Cicer species. A large collection of chickpea germplasm including wild Cicer species has been conserved in different gene banks globally. However, the effective and efficient utilization of these resources is required to develop new cultivars with a broad genetic base. Using core and mini-core collections, chickpea researchers have identified diverse germplasm possessing various beneficial traits that are now being used in chickpea breeding. Further, for chickpea improvement, the genus Cicer harbours alleles/genes for tolerance/resistance to various abiotic and biotic stresses as well as for agronomic and nutrition-related traits. Recent advances in plant biotechnology have resulted in developing large number of markers specific to chickpea in addition to technological breakthrough in developing high-throughput genotyping platforms for unlocking the genetic potential available in germplasm collections.

Pigeonpea (Cajanus cajan (L.) Millspaugh) is an important grain legume crop grown in tropical and subtropical regions of the world. Though pigeonpea has a narrow genetic base, vast genetic resources are available for its genetic improvement. Evaluation of small subsets, such as core (10% of the whole collection) and mini-core collections (about 1% of the entire collection), has resulted in the identification of promising diverse sources for agronomic and nutrition-related traits as well as resistance/tolerance to important biotic/abiotic stresses for use in pigeonpea improvement programmes. Wild relatives of pigeonpea are the reservoir of many useful genes, including resistance/tolerance to diseases, insect pests and drought and good agronomic traits, and also have contributed to the development of cytoplasmic male sterility systems for pigeonpea improvement. Availability of genomic resources, including the genome sequence, will facilitate greater use of germplasm to develop new cultivars with a broad genetic base.

Both chickpea (Cicer arietinum L.) and pigeonpea [Cajanus cajan (L.) Millsp.] are important dietary source of protein while groundnut (Arachis hypogaea L.) is one of the major oil crops. Globally, approximately 1.1 million grain legume accessions are conserved in genebanks, of which the ICRISAT genebank holds 49,485 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 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.

Chickpea (Cicer arietinum) is the second most widely grown legume crop after soybean, accounting for a substantial proportion of human dietary nitrogen intake and playing a crucial role in food security in developing countries. We report the ∼738-Mb draft whole genome shotgun sequence of CDC Frontier, a kabuli chickpea variety, which contains an estimated 28,269 genes. Resequencing and analysis of 90 cultivated and wild genotypes from ten countries identifies targets of both breeding-associated genetic sweeps and breeding-associated balancing selection. Candidate genes for disease resistance and agronomic traits are highlighted, including traits that distinguish the two main market classes of cultivated chickpea—desi and kabuli. These data comprise a resource for chickpea improvement through molecular breeding and provide insights into both genome diversity and domestication.

In chickpea, bottlenecks associated with its domestication and low use of germplasm in improvement programs have resulted in a narrow genetic base and its vulnerability to abiotic and biotic stresses. The core and mini core collections, representing diversity in the entire collection, have been advocated for enhanced utilization of germplasm in crop improvement. A chickpea mini core (211 accessions) was evaluated for agronomic traits from 2000 and 2001 to 2003 and 2004 in post-rainy seasons under irrigated and non-irrigated conditions. The published information on the response of chickpea mini core accessions to stress revealed that 40 accessions had resistance to abiotic stress, 31 to biotic stress, and 24 had no resistance to either of the stresses. The abiotic and biotic stress resistant groups had six accessions in common. The mini core collection accessions were also a part of composite collection accessions in chickpea, which was genotyped using 48 simple sequence repeats (SSRs; BMC Plant Biol. 8:106, 2008). The agronomic evaluation, stress response, and molecular profiling data on 93 accessions, including four controls, were used to identify genetically diverse germplasm with agronomically beneficial traits. A number of genetically diverse accessions possessing agronomically beneficial traits, such as ICC 440, 637, 1098, 3325, 3362, 4872, 7441, 8621, 9586, 10399, 12307, 14402, 15680, and 15686, which meet breeders’ needs, have been identified for use in breeding and genetics to map genomic regions associated with beneficial traits and as source materials for developing high yielding and widely adapted chickpea cultivars with multiple resistance to abiotic and biotic stress.

The narrow genetic base of cultivars coupled with low utilization of genetic resources are the major factors limiting grain legume production and productivity globally. Exploitation of new and diverse sources of variation is needed for the genetic enhancement of grain legumes. Wild relatives with enhanced levels of resistance/tolerance to multiple stresses provide important sources of genetic diversity for crop improvement. However, their exploitation for cultivar improvement is limited by cross-incompatibility barriers and linkage drags. Pre-breeding provides a unique opportunity, through the introgression of desirable genes from wild germplasm into genetic backgrounds readily used by the breeders with minimum linkage drag, to overcome this. Pre-breeding activities using promising landraces, wild relatives, and popular cultivars have been initiated at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) to develop new gene pools in chickpea, pigeonpea, and groundnut with a high frequency of useful genes, wider adaptability, and a broad genetic base. The availability of molecular markers will greatly assist in reducing linkage drags and increasing the efficiency of introgression in pre-breeding programs.

Chickpea is increasingly being grown in tropical areas, and terminal drought is becoming a major constraint to its increased productivity. A trait-based selection approach can achieve further gains in drought tolerance that has been achieved through direct selection for yield. Separation of yield into its components including the rate of partitioning and its duration could permit a better focus on the most relevant trait for yield enhancement under terminal drought. Current work is aimed at understanding the importance of rate of partitioning or the partitioning coefficient (p) as a major contributory trait associated with drought tolerance both in germplasm and breeding lines. A reference collection of chickpea germplasm (n = 280) was evaluated in the field under both terminal drought and optimally irrigated environments; and a set of desi (n = 60) and kabuli (n = 60) advanced breeding lines under terminal drought. Grain yield was associated with its analytical components – crop growth rate (C), reproductive duration (Dr) and p. The path analysis showed that C and p had a large direct positive contribution to yield while Dr had a marginal but negative contribution to yield under drought. The direct contribution of p was the highest but it was marginally reduced by the indirect negative contributions of Dr. However, the total contributions of p to grain yield remained large. The yield of germplasm accessions under drought across the seasons were closely associated (r2 = 0.70) and also the genotype × year interaction was minimum. The contribution of C, Dr and p to grain yield were similar in the advanced breeding lines. However, kabuli breeding lines had a larger variation for p than the desi lines. The results suggest that a conscious selection for greater p will confer greater tolerance to abiotic stresses, given that terminal drought tends to curtail the length of the reproductive period.

Foxtail millet (Setaria italica (L.) P. Beauv.) is an ideal crop for changing climate and food habits of peoples due to its short duration, high photosynthetic efficiency, nutritional richness and fair resistance to pest and diseases. However, foxtail millet yields are low mainly due to the lack of effort for its improvement and the lack of proper utilization of existing genetic variability. To enhance the use of diverse germplasm in breeding programmes, a core collection in foxtail millet consisting of 155 accessions was established. Core collection accessions were fingerprinted using 84 markers (81 simple sequence repeats (SSRs) and three Expressed Sequence Tag (EST)-SSRs). Our results showed the presence of greater molecular diversity in the foxtail millet core collection. The 84 markers detected a total of 1356 alleles with an average of 16.14 alleles (4–35) per locus. Of these, 368 were rare alleles, 906 common alleles and 82 the most frequent alleles. Sixty-one unique alleles that were specific to a particular accession and useful for germplasm identification were also detected. In this study, the genetic diversity of foxtail millet was fairly correlated well with racial classification, and the race Indica showed a greater genetic distance from the races Maxima and Moharia. The pairwise estimate of dissimilarity was >0.50 except in 123 out of 11,935 pairs which indicated a greater genetic variability. Two hundred and fifty pairs of genetically most diverse accessions were identified. This large molecular variation observed in the core collection could be utilized effectively by breeders or researchers for the selection of diverse parents for breeding cultivars and the development of mapping populations.

The chickpea and pigeonpea are protein-rich grain legumes used for human consumption in many countries. Grain yield of these crops is low to moderate in the semi-arid tropics with large variation due to high GxE interaction. In the Indian subcontinent chickpea is grown in the post-rainy winter season on receding soil moisture, and in other countries during the cool and dry post winter or spring seasons. The pigeonpea is sown during rainy season which flowers and matures in post-rainy season. The rainy months are hot and humid with diurnal temperature varying between 25 and 35°C (maximum) and 20 and 25°C (minimum) with an erratic rainfall. The available soil water during post-rainy season is about 200–250 mm which is bare minimum to meet the normal evapotranspiration. Thus occurrence of drought is frequent and at varying degrees. To enhance productivity of these crops cultivars tolerant to drought need to be developed. ICRISAT conserves a large number of accessions of chickpea (>20,000) and pigeonpea (>15,000). However only a small proportion (<1%) has been used in crop improvement programs mainly due to non-availability of reliable information on traits of economic importance. To overcome this, core and mini core collections (10% of core, 1% of entire collection) have been developed. Using the mini core approach, trait-specific donor lines were identified for agronomic, quality, and stress related traits in both crops. Composite collections were developed both in chickpea (3000 accessions) and pigeonpea (1000 accessions), genotyped using SSR markers and genotype based reference sets of 300 accessions selected for each crop. Screening methods for different drought-tolerant traits such as early maturity (drought escape), large and deep root system, high water-use efficiency, smaller leaflets, reduced canopy temperature, carbon isotope discrimination, high leaf chlorophyll content (drought avoidance), and breeding strategies for improving drought tolerance have been di

Chickpea is the third most important pulse crop worldwide. Changes in cropping system that necessitate late planting, scope for expansion in rice fallows and the global warming are pushing chickpeas to relatively warmer growing environment. Such changes demand identification of varieties resilient to warmer temperature. Therefore, the reference collection of chickpea germplasm, defined based on molecular characterization of global composite collection, was screened for high temperature tolerance at two locations in India (Patancheru and Kanpur) by delayed sowing and synchronizing the reproductive phase of the crop with the occurrence of higher temperatures ( ≥ 35°C). A heat tolerance index (HTI) was calculated using a multiple regression approach where grain yield under heat stress is considered as a function of yield potential and time to 50% flowering. There were large and significant variations for HTI, phenology, yield and yield components at both the locations. There were highly significant genotypic effects and equally significant G × E interactions for all the traits studied. A cluster analysis of the HTI of the two locations yielded five cluster groups as stable tolerant (n = 18), tolerant only at Patancheru (n = 34), tolerant only at Kanpur (n = 23), moderately tolerant (n = 120) and stable sensitive (n = 82). The pod number per plant and the harvest index explained ≥ 60% of the variation in seed yield and ≥ 49% of HTI at Kanpur and ≥ 80% of the seed yield and ≥ 35% of HTI at Patancheru, indicating that partitioning as a consequence of poor pod set is the most affected trait under heat stress. A large number of heat-tolerant genotypes also happened to be drought tolerant.

Pigeonpea (Cajanus cajan (L.) Millsp. is one of the most important legume crops as major source for proteins, minerals and vitamins, in addition to its multiple uses as food, feed, fuel, soil enricher, or soil binder, and in fencing, roofing and basket making. ICRISAT's genebank conserves 13,632 accessions of pigeonpea. The extensive use of few parents in crop improvement is contrary to the purpose of collecting a large number of germplasm accessions and has resulted in a narrow base of cultivars. ICRISAT, in collaboration with the Generation Challenge Program, has developed a composite collection of pigeonpea consisting of 1000 accessions representing the diversity of the entire germplasm collection. This included 146 accessions of mini core collection and other materials. Genotyping of the composite collection using 20 microsatellite or simple sequence repeat (SSR) markers separated wild and cultivated types in two broad groups. A reference set comprising 300 most diverse accessions has been selected based on SSR genotyping data. Phenotyping of the composite collection for 16 quantitative and 16 qualitative traits resulted in the identification of promising diverse accessions for the four important agronomic traits: early flowering (96 accessions), high number of pods (28), high 100-seed weight (88) and high seed yield/plant (49). These accessions hold potential for their utilization in pigeonpea breeding programmes to develop improved cultivars with a broad genetic base. Pigeonpea germplasm has provided sources of resistance to abiotic and biotic stresses and cytoplasmic-male sterility for utilization in breeding programmes.

The growth of chickpea (Cicer arietinum L.) is very sensitive to salinity, with the most susceptible genotypes dying in just 25 mm NaCl and resistant genotypes unlikely to survive 100 mm NaCl in hydroponics; germination is more tolerant with some genotypes tolerating 320 mm NaCl. When growing in a saline medium, Cl-, which is secreted from glandular hairs on leaves, stems and pods, is present in higher concentrations in shoots than Na+. Salinity reduces the amount of water extractable from soil by a chickpea crop and induces osmotic adjustment, which is greater in nodules than in leaves or roots. Chickpea rhizobia show a higher ‘free-living’ salt resistance than chickpea plants, and salinity can cause large reductions in nodulation, nodule size and N2-fixation capacity. Recent screenings of diverse germplasm suggest significant variation of seed yield under saline conditions. Both dominance and additive gene effects have been identified in the effects of salinity on chickpea and there appears to be sufficient genetic variation to enable improvement in yield under saline conditions via breeding. Selections are required across the entire life cycle with a range of rhizobial strains under salt-affected, preferably field, conditions.

Grain legumes are rich resource of dietary proteins, minerals, and vitamins; however, productivity remains low, narrow genetic base of the cultivars being one of the several reasons to low productivity. Worldwide approximately half a million legume germplasm acceSSIOns are preserved in genebanks. However, there has been limited use of these resources in crop breeding. Core collection (10% of the entire collection), a subset of accessions representing at least 70% of the genetic variation in the entire collection of the species, has been suggested as a gateway to enhance utilization of germpJasm. Core and mini core (10% of core) collections have been reported in several legumes that when evaluated identified new sources of variation for agronomic traits including resistance to biotic and abiotic stresses. Legumes genomics resources in the past lagged behind cereals. However, situation dramatically changed with emergence of Medicago truncatula, Lotus japonicus, and Glycine max as models for comparative genomics within legume family. Several genomic resources including markers, maps, transcriptomics, proteomics, metabolomics, and bioinformatics resources have been developed. These resources in model plants will not only allow investigation of basic processes important to legumes, but also open the possibility to transfer those processes to- or locate them in other crop species including several legumes. Several genomic projects are developing tools for less-studied legumes which are economically important in Africa and Asia. These genetic and genomic resources represent major milestones in the history of…

This chapter discusses the target growing environments and sensitivity of pearl millet, sorghum, maize, groundnut, chickpea and pigeon pea to drought; phenotypic screens and natural genetic variations for response to drought; empirical and trait-based breeding methods to enhance drought tolerance; and deployment of emerging biotechnological tools (DNA markers and transgene) to enhance crop adaptation and productivity under drought stress conditions.

Grain legumes such as chickpea, pigeon pea, cowpea, field pea, lentil, faba bean, black gram, green gram, grasspea and Phaseolus, have important roles in food and nutritional security, and sustainable crop production. Several insect pests damage these crops, of which gram pod borer (Helicoverpa armigera), spotted pod borer (Maruca vitrata), spiny pod borer (Etiella zinckenella), pod fly (Melanagromyza obtusa), stem fly (Ophiomyia phaseoli), aphids (Aphis craccivora and Aphis fabae), white fly (Bemisia tabaci), defoliators (Spodoptera litura, S. exigua and Amsacta spp.), leafhoppers (Empoasca spp.), thrips (Megalurothrips dorsalis and Caliothrips indicus), blister beetles (Mylabris spp.) and bruchids (Callosobruchus chinensis and Bruchus pisorum), cause extensive losses. Several sources of resistance to insects have been identified in grain legumes, and several morphological and biochemical traits associated with resistance to insects have also been identified. Genetic linkage maps were developed for some of the grain legumes. However, the accuracy and precision of phenotyping for resistance to insect pests remains a critical constraint in many crops. There are very few reports concerning the application of molecular markers for resistance to insect pests in grain legumes. There is a need for precise phenotyping, mapping of QTLs associated with insect resistance, and use them in conjunction with morphological and biochemical markers to develop cultivars with resistance to insect pests.

Chickpea is an important grain legume...

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