Reaction of rice varieties to winter hardiness.

The reaction of rice varieties to winter hardiness was evaluated in the first crop of 1970 at the Chiayi Agricultural Experiment Station. The winter survival of young rice plants in the dry nursery indicated that japonica varieties were more resistant to winter injury than indica varieties. Varieties developed at or native of Taiwan showed better survival from winter killing than those from tropical regions of the United States, Philippines, and India. Visual estimates of chlorosis on rice seedlings in the ordinary wet nursery showed that varieties of poor winter survival generally developed severe chlorosis. Reaction of heterogenous populations were usually intermediate between those of the parents or components involved.