HETEROSIS AND COMBINING ABILITY ESTIMATE AND PATH ANALYSIS IN OILSEED RAPE (BRASSICA NAPUSL.)
Yu Hui;Guan Chunyun;Wang Guohuai, (The Department of Agronomy)
Crosses (without reciprocals) of 6×6 diallel are conducted tostudy the heteroses of 14 characters, combining ability of 12 characters, rela-tionships between heteroses of 11 characters and the single-plant heterosis ofseed yield of 15 F_1. The results are as follows: 1. The F_1 hybrids exhibit positive mean heteroses: 37.1% for single-plantpods and 34.3% for single-plant seed yield. In respect of absolute data andheteroses the crosses of diverse origin (Asian(A)×European(E)) are higherthan the crosses of the same origin (A×A and E×E) in most of importantagronomic characters. 2. General combining ability squares and specific combining ability meansquares are highly significant for all 12 characters, showing both additive andnon-additive genetic effects being important for these characters. 3. The effect combining ability of single-plant seed yield results from com-plementation of combining ability of direct yield components. Heterosis hasclose relationship with specific combining ability effect, but with general com-bining abitity effect. So heterosis can be predicted according to sepcific combi-ning ability effect. 4. Single-plant heterosis of seed yield has a highly significant positivecorrelation with that of primary branches, secondary branches and pods.