Combining ability analyses of parents in two-level diallel cross experiment of Chinese fir.

There were two sets of two level diallel cross experiments at the level of provenance and individual in Chinese fir which were analyzed in this paper. The parents of set A mainly from the center distribution areas were selected in growth traits and had a high genetically improved level. The parents of set B mostly from the marginal distribution areas had a low genetically improved level. The analysis result of combining ability showed that the cross between provenances had a significant difference predominantly due to the GCA effect. At the level of individual, the GCA variance was less than the SCA variance in set A, but it was converse in set B. Therefore, in the procedure of genetic improvement of growth traits in Chinese fir, SCA and GCA are of relative importance. For those materials which were tested by GCA, the next breeding work should be paid on the cross to achieve high SCA. As for the material which hasnt been tested by GCA before, the GCA test is more important than the SCA test.