Interactions between two QTLs for time to anthesis on spike development and fertility in wheat

Abstract

AbstractEarliness per se (Eps) genes are reported to be important in fine-tuning flowering time in wheat independently of photoperiod (Ppd) and vernalisation (Vrn). UnlikePpdandVrngenes,Epshave relatively small effects and their physiological effect along with chromosomal position are not well defined. We evaluated eight lines derived from crossing Paragon and Baj (late and early flowering respectively), vernalisation insensitive, to study the detailed effects of two newly identified QTLs,Eps-7DandEps-2Band their interactions under field conditions. The effect of both QTLs were minor but their effect was modulated by the allelic status of the other. While the magnitude of effect of these QTLs on anthesis was similar, they are associated with very different profiles of pre-anthesis development which also depends on their interaction.Eps-7Daffected both duration before and after terminal spikelet while not affecting final leaf number (FLN) soEps-7D-earlyhad a faster rate of leaf appearance.Eps-2Bacted more specifically in the early reproductive phase and slightly altered FLN without affecting the leaf appearance rate. BothEps-7Dand2Baffected the spike fertility by altering the rate of floret development and mortality. The effect of the latter was very small but consistent in that the -lateallele tended to produced more fertile florets.