VARIATIONS IN THE CROSSABILITY OF COMMON WHEAT CULTIVARS WITH CULTIVATED BARLEY

Differences in crossabilities of 23 common wheat cultivars, Triticum aestivum, were investigated by crossing those with cultivated barley, Hordeum vulgare cv. 'Betzes'. Simultaneously, the wheat cultivars were crossed with rye, Secale cereale, in order to clarify the relationship between the crossabilities of wheat with barley and rye. Common wheat cultivars were used as female parents in both crosses, and number of embryos and seeds in wheat-barley and wheat-rye crosses were counted. Crossabilities of wheat with barley ranged from 0 % to 27.1 %, which were classified into five classes based on t-tests between all of the cross combinations. The highest class consisted of two cultivars, 'Aobakomugi' (27.1 %) and 'Norin 61' (19.0 %). Correlation between the crossabilities of wheat with barley and rye was not significant (r = 0.437, P > 0.05). However, after the crossability values of the two cultivars, 'Aobakomugi' and 'Nobeokabouzu', were excluded, the coefficient was highly significant (r = 0.629, P < 0.01), since these cultivars showed only high crossabilities with barley or rye, respectively. These data suggest that the crossability of wheat with barley is also controlled by Kr alleles, which are known to control crossability with rye. However, there are exceptional wheat cultivars, in which crossability gene(s) other than the Kr system exist, that need to be considered.