The Physiological Basis for Yield Differences between Four Genotypes of Groundnut (<i>Arachis hypogaea</i>) in Response to Drought. II. Solar Radiation Interception and Leaf Movement

Abstract

SUMMARY Four genotypes of groundnut grown with limited irrigation during the post-rainy season in Central India produced similar amounts of dry matter per unit of intercepted solar radiation (e) before pod-filling, although different e values were observed during pod-filling. The relation between cumulative transpiration and intercepted radiation was similar for all genotypes. When drought became severe, fractional radiation interception (f) was reduced by folding of leaves, with little decrease in leaf area (L). The ratio f/√L was used as an index of the degree of leaf folding and was correlated with leaf water potential. The degree of folding varied with genotype and may have contributed to the observed differences in e and the dry matter:water ratio (q). The genotype EC76446(292) had the smallest q and largest f/√L ratio (the poorest radiation avoidance), while Kadiri 3 had the largest q and smallest value of f/√L.