オオムギにおける純粋早晩性の品種変異と適応的意義

Heading time of is a complex character, which is controlled by several internal factors, namely, vernalization requirement, photoperiodic response and earliness in a narrow sense (ENS). The ecological significance of vernalization requirement and photoperiodic response has been clarified. However, the significance of ENS is not explained well. In this study, we examined the varietal variation of ENS, its geographical distribution and significance of ENS for regional adaptability in barley. The ENS was estimated from the number of days from sowing to flag-leaf emergence of sufficiently vernalized plants grown under a 24-h. photoperiod at 20℃ condition. The variation of ENS was determined from the number of leaves and leaf emergence intervals under the controlled condition. The ENS of 1,017 barley varieties ranged from 12 to 28 days. ENS was shortest in varieties from low-latitudes, while it was longer in varieties from high-latitudes and very low-latitudes. Multiple regression analysis for heading time(Y) on the ENS(X1) and the photoperiodic response(X2) was carried out using various data obtained from different experiment sites and sowing times. The multiple correlation was highly significant in all cases. It was clear that the ENS played an important role for determining heading time in the spring-sown conditions, while the photoperiodic response did in the fall-sown condition.