옥수수 黑條萎縮病 抵抗性의 遺傳

Inheritance of resistance to black streaked dwarf virus(BSDV) in corn(zea mays L.)

Black streaked dwarf virus(BSDV) is one of the most important diseases of corn(Zea nays L.) in Korea. Dissemination of new high yielding corn hybrids is limited to the southern areas due to only this epidemic disease. There are no known published reports concerning the inheritance of reaction to BSDV in corn. This study was conducted to select resistant genotypes to BSDV and elucidate the genetic control of resistance to BSDV. Total of 965 local collections, introduced inbreds and hybrids were screened under field conditions in 1980 and 1981, 8-entry diallel crosses were tested in 1980 and generation mean analysis of parental, F₁, F₂ and backcross populations from the crosses of 5 resistant and susceptible lines were made under field conditions in 1981. Nine Korean local collections, KL-2, KL-10, KL-11, K79004, K79091, K79111, K79123 and K79124, and one introduced inbred, Ga 209, were selected as resistant genotypes to BSDV. Only specific combining ability was appeared to be significant in determination of BSDV resistance in the diallel analysis, indicating the relative importance of nonadditive genes for BSDV resistance. Crosses between resistant local collections and susceptible introduced inbreds such as KS15×KL-7, KS15×KL-1, KL-4×KS15 and KL-5×A635 showed high specific combining ability effects to increase resistance to BSDV in their F₁s. Generation mean analysis also indicated that dominance effect was more important than additive gene effect in inheritance of resistance to BSDV in corn, although the relative importance varied with the populations. Significant heterosis effect was also detected between resistant and susceptible lines. This study suggested that BSDV reaction in tested lines was conditioned by primarily nonadditive genes and breeding for resistant to this disease should be effectively accomplished by reciprocal recurrent selection procedure.