Résumé:
The main objective of the present study is the evaluation of several genotypes of beans Phaseolus vulgaris L. cultivated in Algeria for phenological, physiological and phytochemical traits under salt stress conditions. According to their responses to salinity and their phenotypes, four parents were selected. To carry out this study a half-diallel cross between the parents was undertaken producing six F1 hybrids; the six F1 hybrids were planted to allow self-fertilization and the production of the F2 offspring. All F1 and F2 populations and their parents were planted in a complete randomized block design, under three salt treatments 0, 50 and 100mM for the evaluation of phenological, physiological and phytochemical characteristics, the results obtained were subjected to diallel analysis and then genetically analyzed using SSRs and SNPs as well as a single marker analysis to highlight the correlation between phenotypic and genotypic data. The diallel analysis revealed high significant genotypic variations between the four parents and their six F1 hybrids. General and specific combining abilities were highly significant for all traits studied under all conditions, revealing the important role of both additive and dominant genetic effects for heredity of the traits under study. Parental genotypes Améilore Roza and Coco nain proved to be the best combiners for salinity tolerance; on the other hand the hybrids Amina x Améliore Roza; MGT x Améliore Roza and Coco nain x Amina recorded a high significant percentage of heterosis. Molecular analysis showed that populations from the half diallel cross have a high genetic diversity, these populations can be used later for the production of RILs; in addition, single marker analysis revealed that several SSRs markers were associated with the different traits studied, the markers BMd37 (LG6) BM200 and ATA243 (LG1) showed a strong association with the production of polyphenols and total flavonoids, these markers can be linked to important genes implying a salinity tolerance. These results indicate a high genetic variability in bean populations and a possibility of genetic improvement under salt stress, especially for the biosynthesis of secondary metabolites.
