|Grusak, Michael - Mike|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/11/2005
Publication Date: 7/20/2005
Citation: Abbo, S., Molina, C., Jungmann, R., Grusak, M.A., Berkovitch, Z., Reifen, R., Kahl, G., Winter, P., Reifen, R. 2005. Qtl governing carotenoid concentration and weight in seeds of chickpea (Cicer arietinum L.). Theoretical and Applied Genetics. 111(2):185-195. Interpretive Summary: Chickpea is an important food legume that provides many dietary nutrients and phytochemicals, especially in Asian and Middle Eastern countries. Although predominantly consumed for its protein content, chickpea seeds also contain various caroteniods that can serve as vitamin A precursors, and/or as anti-oxidant molecules. In order to increase the levels of carotenoids in chickpea seeds through conventional breeding, it is important to understand the genetic basis for carotenoid concentration in the seeds. Thus, a cross was made between a cultivated Israeli chickpea and a wild chickpea relative, which differed in seed carotenoid levels. The two parents also differed in average seed weight. An analysis of progeny from this cross allowed us to identify regions of the genome (i.e., the full set of genes that make up an individual species) that were associated with elevated seed concentrations of various carotenoids. We also demonstrated that low seed weight was not a prerequisite for high seed carotenoid concentration (i.e., not a concentrating effect). This work will assist us in developing new, large-seeded varieties of chickpea with improved carotenoid nutritional quality.
Technical Abstract: Chickpea is a staple protein source in many Asian and Middle Eastern countries. The seeds contain carotenoids such as beta-carotene, cryptoxanthin, lutein, and zeaxanthin, in amounts above the "golden rice" level. Thus, breeding for high carotenoid concentration in seeds is of nutritional, socio-economic and economic importance. To study the genetics governing seed carotenoids in chickpea, the relationship between seed weight and concentration of beta-carotene and lutein was studied by HPLC in segregating progeny from a cross between an Israeli cultivar and wild C. reticulatum Ladiz. Seeds of the cross progeny, varied in their carotenoid concentration (heritability estimates ranged from 0.5 to 0.9). Negative genetic correlation was found between mean seed weight and carotenoid concentration in the F3, but not in a random sample of F4 plants. To determine the loci responsible for the genetic variation observed, the population was genetically mapped using 91 STMS and two CytP450 markers to generate a genetic map comprising 344.6 centi-Morgans in nine linkage groups. Using quantitative data for beta-carotene and lutein concentration and seed weight collected for the seeds of the F2 population, quantitative trait loci (QTL) were identified by interval mapping. At a LOD-score of 2, four QTL for beta-carotene concentration, a single QTL for lutein concentration and three QTL for seed weight were detected. This work may assist in improving the nutritional quality of chickpea.