Genotype by Environment Interaction of Sorghum Flowering Time

Flowering time is a complex trait that controls adaptation of plants to their local environment. The initiation of flowering in plants is controlled by endogenous and environmental signals. Sorghum is a short-day tropical species that exhibits substantial photoperiod sensitivity and delayed flowering in long days. Genotypes with reduced photoperiod sensitivity enabled sorghum’s utilization as a grain crop in temperate zones worldwide. In this study, we are trying to investigate the G × E interaction of sorghum flowering time and provide possible solutions to tackle this issue in genetics research and plant breeding. Flowering times of 250 entries from a sorghum recombination inbred line (RIL) population were phenotyped. We observed significant G × E interaction for this trait. In Puerto Rico, a short day environment, all entries in this population flowered in a 20 days period. However, in Manhattan KS, a long day environment, the range of flowering times extended to approximately 70 days. Some photoperiod sensitive entries flowered early in short day environment, but extremely late in long day environment. This population was genotyped using genotyping by sequencing (GBS). Two QTLs located on chromosome 6 and 10 explained 45% and 12% of the phenotypic variation, respectively. Finding the genome locations of the underlying genes could provide valuable information for marker assisted sorghum breeding.