Legume genetic resources: management, diversity assessment, and utilization in crop improvement

Abstract

Grain legumes contribute significantly to total world food production. Legumes are the primary source of dietary proteins in many developing countries, where protein hunger and malnutrition are widespread. Grain legumes germplasm constitute ~15% of the 7.4 M accessions preserved globally. Nearly, 78% of the CGIAR?s, 0.217 M accessions, have been characterized, compared to 34% of national genebank collections. Interestingly, limited data on grain quality are available as the primary focus has been on morpho-agronomic traits. Clearly, more resources should be targeted on biochemical evaluation to identify nutritionally rich and genetically diverse germplasm. The formation of core and mini core collections has provided crop breeders with a systematic yet manageable entry point into global germplasm resources. These subsets have been reported for most legumes and have proved useful in identifying new sources of variation. They may however not eliminate the need to evaluate entire collections, particularly for very rare traits. Molecular characterization and association mapping will further aid to insights into the structure of legume diversity and facilitate greater use of collections. The use of high resolution elevational climate models has greatly improved our capacity to characterize plant habitats and species? adaptive responses to stresses. Evidence suggests that there has been increased use of wild relatives as well as new resources resulting from mutagenesis to enhance the genetic base of legume cultigens.Peer reviewe

Legume Crops Phylogeny and Genetic Diversity for Science and Breeding

“…However, only a small percentage of these collections have been characterized for biochemical traits. More emphasis and funding are needed in order to generate data on biochemical characteristics associated with biotic and abiotic stresses (Upadhyaya et al, 2011). The Global Crop Diversity Trust (GCDT) supports the development of global crops (including legumes) and regional strategies for ex situ conservation and utilization of crop diversity.…”

“…cardenasii, A. diogoi, A. batizocoi, A. ipaënsis, A. duranensis, A. gregoryi, A. linearifolium, A. magna, A.valida, A. kempffmercadoi, A. stenosperma and A. hoehnei Upadhyaya et al, 2011; genebanks for client-selected accessions, including multi-trait queries.…”

“…Of the nine sections, Arachis is the largest section, comprised of 32 species, including the cultivated groundnut (A. hypogaea) (Krapovickas and Gregory, 1994;Valls and Simpson, 2005). All species within the Arachis sections are found mostly in Brazil, followed by Paraguay, Argentina and Uruguay (Upadhyaya et al, 2011). Arachis species can be grouped into nine sections comprised of 80 species with both annual and perennial life cycles (Krapovickas and Gregory, 1994;Valls and Simpson, 2005).…”

“…Establishment of such a permanent introgression library with characterized genomic fragments of wild crop relatives in a defined genetic background will allow phenotypic characterization of an unlimited number of target traits, which, coupled with molecular tools, will provide a means of final gene identification and their subsequent incorporation, pyramiding in desired genotypes, ultimately leading to better performing commercial cultivars. So far, not many such series of lines have been developed in grain legumes, but there are several ongoing efforts to establish them in pea (Smýkal and Kosterin, 2010;Smýkal et al, unpublished), beans (Muñoz et al, 2004;Blair et al, 2006;Blair and Izquierdo, 2012), groundnut (Foncéka et al, 2009) and other legumes (reviewed in Upadhyaya et al, 2011). Intergeneric legume hybrids have been critically reviewed in McComb (1975), which found insufficient evidence for all reported crosses due to misleading paper titles, confusion of vegetative with generic hybrids, the occurrence of patrocliny, and the frequent occurrence of misplaced generic boundaries.…”

Genetic diversity studies in pea (Pisum sativum L.) using simple sequence repeat markers

“…Currently, no international center conducts pea breeding and genetic conservation (Upadhyaya et al, 2011). Moreover, a high level of duplication exists between the collections, giving a misleading impression of the true level of diversity (Maxted et al, 2010;Smýkal et al, 2011).…”