Genetic factors influencing female seed set to improve the effectiveness of hybrid sorghum seed production

This PhD investigates the genetic and floral factors influencing female seed set in sorghum, with the aim of improving hybrid seed production efficiency. Female parent lines can differ substantially in their ability to set seed even when male sterility is maintained and a common pollen source is provided, but the factors underlying this variation remain poorly understood. The project combines field trials, controlled pollination experiments, quantitative floral phenotyping and genome-wide association studies to investigate these differences. Seed set is evaluated in 466 cytoplasmic male-sterile lines across four trials to quantify genetic variation, assess consistency across environments and identify associated genomic regions. Detailed measurements of stigma exsertion and stigma, style and ovary morphology in a subset of 255 lines are used to examine relationships between female floral characteristics and seed set. Complementary experiments investigate variation in the duration of stigma receptivity and its implications for successful fertilisation, while a broader sorghum diversity panel is used to investigate the genetic control of floral morphology. Together, these studies aim to identify traits and genetic regions that could support earlier selection of female parents with improved seed-production potential.