Abstract
The heritability of gelatinization characteristics measured by RVA, thousand kernel weight and grain whiteness were examined in progenies of the cross between Koganemochi with high hardness of rice cake and Fukushima mochi 8 with superior cool weather tolerance and preharvest sprouting tolerance, to develop waxy rice with superior cultivation properties and processing properties for rice cake. The heritability of peak temperature and grain whiteness was high and that of maximum viscosity and breakdown was low. There was a negative genetic correlation between gelatinization temperature or peak temperature and thousand kernel weight, but the correlation coefficients were low. The genetic correlation of gelatinization temperature, and peak temperature with grain whiteness was considered to be nearly 0 because the genetic correlation value was negative and positive, when the traits were selected directly and indirectly, respectively. Gelatinization temperature and peak temperature showed positive correlations with cool weather tolerance, but the correlation coefficient was low. Gelatinization temperature, peak temperature and grain whiteness showed positive correlations with ripening temperature. Culm length and ear length showed negative correlations with ripening temperature. It was considered that the short-culmed cultivar with superior hardness of rice cake was capable to be developed, and that it was necessary to increase the population size in order to obtain cultivars with superior hardness of rice cake and superior cool weather tolerance. It is also necessary to consider the decrease of thousand kernel weight for selecting high gelatinization characteristics.
