Evaluation of Water Deficit Tolerance Indices in New Hybrids of Maize (Zea mays L.) with SIMMYT Origin

Regarding the insufficient water resources, developing of cultivars with high tolerance to water deficit can be very effective to optimize water consumption. To identify maize hybrids with higher tolerance to water deficit, 52 single cross hybrids were field evaluated according to a randomized complete block design with three replications in each irrigation regime. The hybrids were produced through crossing of 13 inbred lines from CIMMYT germplasms with four testers of A679, K166B, K18 and MO17. Two check hybrid varieties (KSC704 and KSC705) were included for comparison.  Two irrigation regimes including a normal and a deficit irrigation based on 65% water requirement of plants were applied during two growing seasons of 2014 and 2015 at the Research Station of the Agriculture and Natural Resources of Kermanshah Province. The drought tolerance and sensitive indices were calculated based on grain yield (t/ha) of hybrids at two irrigation regimes. The results of analysis of variance showed significant differences among the hybrids for grain yield and all the indices. The seed yield of hybrids in normal irrigation condition varied from 8.7 to 15.2 t/ha. This range was 4.9 to 10 t/ha in deficit irrigation condition. The cluster analysis classified the hybrids in three distinctive groups. It was recognized that hybrids number 51, 18, 45, 48, 21, 27, 23, 19, 20, 28, 38, 14 and 26 were superior than the others in terms of water deficit tolerance and grain yield. The PCA analysis showed that hybrids number 48, 45, 18 and 51 with high yield potential can be introduced as more promising ones for maize production in normal irrigation condition. However, hybrids 19, 23, 27, 25, 21, and particularly 9 were recognized more suitable for maize production in water deficit condition.