Effects of Drought on Characters Related to Nitrogen Fixation in Peanut

Abstract

Twelve peanut genotypes were tested under three water regimes in two greenhouses to investigate the effects of drought on biomass production and N2 fixation. Drought reduced biomass production from 36.5 to 56.0% and reduced nitrogen fixation from 26.8 to 68.8%. Most genotypes with high biomass production under Field Capacity (FC) had high reduction in biomass production under drought conditions, but fewer genotypes with high N2 fixed under FC showed high reduction in N2 fixed. Biomass production under FC in general gave more contribution to biomass production under drought conditions than did the reduction. N2 fixed under FC and the reduction in N2 fixed contributed similarly to N2 fixed under drought conditions. Positive and significant correlations between N2 fixed and biomass production were found at FC and 2/3 available soil water (AW), but the correlation was not significant at 1/3 AW. Tifton-8 was the best genotype for high N2 fixed under FC and KK 60-3 was the best genotype for low reduction. Correlations between N2 fixed and nodule dry weight and shoot dry weight were high and consistent across water regimes. This information is important for breeders to develop peanut cultivars with reasonably high nitrogen fixation under drought conditions