Application of Drought Index in Soybean Improvement for Northeast Thailand

Abstract

Drought Index (DI), the ratio of yield under water-stress conditions to yield under normal conditions, was verified in the performance of 11 soybean lines in 1986 at the Roi Et Field Crops Experiment Station in Northeast Thailand. The results indicated that the DI gave an accurate estimate of drought tolerance which was verified in measurements of root penetration using the isotope P32. There was also a significant correlation between Harvest Index and grain yield; however, this relationship existed only under the non-stressed conditions.