Abstract
The relationship between snow tolerance and growth characteristics in early winter was investigated using 41 varieties of broad bean. Varietal differences in snow tolerance were detected after 36 and 61 days of continuous snow cover. After 61 days of snow cover, only 2 varieties survived and 39 varieties were injured seriously. After 36 days of snow cover, 4 varieties were injured seriously but 37 varieties survived. The 41 varieties examined were classified into 3 groups based on their snow tolerance; hardy, intermediate and susceptible. To breed a snow tolerant variety, varieties in each group were bred under similar environmental condition. Several significant correlations were recognized between the degree of snow injury and some growth characteristics in early winter. The hardy varieties had a short plant length, light fresh and dry weights of foliage, high percentage of dry weight of foliage and late floral differentiation, whereas the susceptible varieties showed opposite tendencies. In the susceptible group, floral differentiation started in the early stage of growth and the floral buds developed markaedly before winter, suggesting that the susceptible varieties belong to spring type of broad bean. These results show that the varietal difference in snow tolerance of broad bean is closely correlated with the development of floral differentiation and morphological characters at early winter.
