|Pimratch, S -|
|Jogloy, S -|
|Vorasoot, N -|
|Toomsan, B -|
|Kesmala, T -|
|Patanothai, A -|
Submitted to: Asian Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 15, 2010
Publication Date: September 15, 2010
Citation: Pimratch, S., Jogloy, S., Vorasoot, N., Toomsan, B., Kesmala, T., Patanothai, A., Holbrook Jr, C.C. 2010. Effects of drought on characters related to nitrogen fixation in peanut. Asian Journal of Plant Sciences. 9:402-413. Interpretive Summary: Drought is a major factor limiting yield of peanut under rainfed conditions in many countries. Drought resistant peanut lines have been identified, however, the physiological basis for achieving high yield under drought stress is not known. Information on physiological traits contributing to high yield under drought stress might reveal the underlying mechanism from which improved strategies could be developed to enhance the effectiveness and progress in breeding for drought resistance in peanut. The objective of this study was to determine the effect of drought on biomass production and N2 fixation by evaluating the relative values of these two traits under well watered and water-stress conditions. Twelve peanut genotypes with varying levels of drought tolerance were tested under field conditions in two dry seasons in Northeastern Thailand. Data were recorded on biomass production and N2 fixation under well watered and water-stress conditions. Positive relationships between N2 fixed and biomass production were found at both levels of drought stress, and the relationship was stronger the more severe the drought stress. These results suggested that the ability to maintain high N2 fixation under drought stress could aid peanut genotypes in maintaining high yield under water limited conditions.
Technical 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.