Grain protein estimation and SDS-PAGE profilingof six important arid legumes

Grain protein content and protein profiles of six arid grain legumes belonging to three different tribes were studied. Average grain protein (per cent) of horse gram, cowpea, moth bean, guar, chickpea and green gram was 20.29, 22.8, 22.6, 20.6, 21.82, and 20.40 respectively. All the six arid legumes were clearly differentiated based on the protein banding patterns generated through SDS-PAGE. The molecular weight range of proteins in different legumes was observed to be ~16 to ~250kD. Interestingly, in chickpea, moth bean and horse gram proteins >100kD were not mostly observed. Further, distinct proteins were observed indicating inter-varietal differences in horse gram (CRHG-19), cowpea (RC-101) and guar (HG-2-20), which could be useful in varietal identification. The different legumes were broadly clustered in to four clusters. Further, chickpea (Cicereae), green gram and cowpea (Phaseoleae) were clustered together. The similarity indexes of varieties and individual crops ranged from 0.667 to 0.950 and 0.425 to 0.821 respectively. Though the six legumes belong to Leguminosae they have distinct protein profiles which could be useful in species/varietal identification.