Effect of high temperature on the reproductive development of chickpea genotypes under controlled environments

High temperature during the reproductive stage in chickpea (Cicer arietinum L.) is a major cause of yield loss. The objective of this research was to determine whether that variation can be explained by differences in anther and pollen development under heat stress: the effect of high temperature during the pre- and post-anthesis periods on pollen viability, pollen germination in a medium, pollen germination on the stigma, pollen tube growth and pod set in a heat-tolerant (ICCV 92944) and a heat-sensitive (ICC 5912) genotype was studied. The plants were evaluated under heat stress and non-heat stress conditions in controlled environments. High temperature stress (29/16 degrees C to 40/25 degrees C) was gradually applied at flowering to study pollen viability and stigma receptivity including flower production, pod set and seed number. This was compared with a non-stress treatment (27/16 degrees C). The high temperatures reduced pod set by reducing pollen viability and pollen production per flower. The ICCV 92944 pollen was viable at 35/20 degrees C (41% fertile) and at 40/25 degrees C (13% fertile), whereas ICC 5912 pollen was completely sterile at 35/20 degrees C with no in vitro germination and no germination on the stigma. However, the stigma of ICC 5912 remained receptive at 35/20 degrees C and non-stressed pollen (27/16 degrees C) germinated on it during reciprocal crossing. These data indicate that pollen grains were more sensitive to high temperature than the stigma in chickpea. High temperature also reduced pollen production per flower, % pollen germination, pod set and seed number.