Effect of Heat Stress on Seed Production of Some Sorghum Varieties Under Irrigation in Northern Nigeria

Exposure of sorghum (sorghum bicolor) during flowering time for a period of 10-15 days to high temperature stress (>36-38oC) reduced pollen germination, failure of fertilization and flower abortion. A number of improved varieties of sorghum have recently been released for the Sudan and Sahel zones of Nigeria, with their dissemination limited by seed availability. To improve the supply of Breeder and Foundation seeds for production of certified, these varieties; SAMSORG 45 and SAMSORG 46 with two old but popular varieties SAMSORG 41 and SAMSORG 17 were grown under irrigation at Dadinkowa (10.18N, 11.27S) to assess their productivity during the dry season at two planting dates (October and January) for 2 seasons (2015 & 2016). Result showed that October planting which flowering and seed set coincided with the average maximum temperature of 27oC recorded in January produced good seed while December/January planting which flowering and seed set coincided with average maximum temperature of 42oC recorded in April had poor or no seed set on panicles especially in 2016. Rise in the average maximum temperature (2016) in the month of March (350C) and April 2016 (410C) resulted to 90-100% no seed set on SAMSORG 17, SAMSORG 45 and SAMSORG 46 as it coincided with the flowering time thus producing sterile panicle. This suggest that planting date and temperature significantly affect seed production of sorghum in the dry season.