Micronutrient diversity in pole and bush type Dolichos bean germplasm: identification of gene sources from biofortification perspectives

Exploring the nutritional potential of underutilized legumes such as Dolichos bean (Lablab purpureus L.) is of great significance, particularly, in view of accomplishing the United Nation's Sustainable Development Goal number two, which emphasizes on improving food and nutrition security by 2030. A thorough understanding of genetic variability is crucial for developing biofortified cultivars of Dolichos bean. In this study, the Dolichos bean genotypes represented by pole and bush types (28 bush and 19 pole types) were assessed for genetic variability for Cu, Mn, Fe and Zn contents. Pole type genotypes had higher average contents for all micronutrients except manganese. Among micronutrients, Cu, Fe, Mn and Zn, content ranged from 10.10–19.95, 77.13–331.93, 22.78–46.40 and 42.03–102.85 mg kg−1 in pole type, and 8.2–18.5, 50.8–99.3, 25.65–53.25 and 37.15–63.25 mg kg−1 in bush type beans, respectively. Strong positive correlations between Cu, Fe and Zn concentrations occurred, which indicates the possibility of simultaneous improvement of these nutrients. Pod pigmentation was positively correlated with contents of Fe and Zn. There was an association of micronutrients with yield. The pole genotypes VRSEM-1000, VRDB-01 and VRSEM 109 and bush type genotypes VRBSEM-3, VRBSEM-35 and VRBSEM- 200 are good source of microelements and high yielders. Gene sources with enhanced nutrients may be used as cultivated forms or as input material for breeding nutritionally rich biofortified varieties of bean.