Screening for Drought Tolerance in Maize Hybrids using Drought Indices

A study was conducted to select extra-early maize hybrids for drought tolerance and investigate the efficacy of different drought indices. The material consisted of 10 single cross hybrids which were selected from 66 single cross hybrids using IITA base index. The initial experiment was conducted at Ikenne and was laid in a randomized incomplete block design with two replicates. Data collected were subjected to analysis of variance (ANOVA) after which the best ten were selected using a base index. The selected hybrids were further subjected to estimates of SSI, STI, GMP, MP, TOL, DTE, YI, GOL, HARM, and YSI. The results revealed that most of the hybrids were tolerant to drought. However, hybrids TZdEEI 7 × TZEEI 79 and TZdEEI 7 × TZEEI 63 were found to be the most promising drought tolerant hybrids. STI, GMP, GOL, MP and YI were positively correlated to yield under drought stress conditions and were able to separate hybrids under ‘A’ group from other groups. This is an indication that the indices can be used as a measure of drought tolerance in maize. Keywords: Maize hybrids, Extra-early, drought tolerance, drought indices.