Moth bean (Vigna aconitifolia) cultivars compared for root nutrient uptake efficiency in arid NW India

To investigate the genetic variation of N, P, K and Na inflow under rain-fed conditions, 12 moth bean (Vigna aconitifolia (Jacq) Marechal) genotypes were grown in field plots on a typical Camborthid soil. The inflow was calculated at the critical period, between 5 and 6 weeks of planting the crop. The N inflow among cultivars ranged from 6.98 to 15.66×10−9 mol cm−1 root day−1 and was maximum in the genotype Exp-109 that also resulted in the maximum grain yield. The P influx varied eight times (from 0.03 to 0.24×10−9 mol cm−1 root day−1) and was highest in the early flowering cultivar RMO-435. The K influx ranged from 0.04 to 0.15×10−9 mol cm−1 root day−1 and the maximum inflow was observed again in the genotype Exp-109. Sodium influx varied from 0.04 to 0.09×10−9 mol cm−1 root day−1 and was maximum in the genotypes RMO-257 and RMM-12. Grain yield was correlated with N (r=0.880***), P (r=0.896***) and K influx (r=0.925***) at the critical growth stage. The results suggested that rate of influx of N, P and K was in general maximum in the high-yielding genotypes which supports a basis for productivity under such situations and that enormous variability existed for the influx of these nutrients (N, P and K). These results provide opportunity to study the genetics of nutrient influx and its use in improved productivity even on arid soils.