옥수수 後期綠體性 형질의 雜種强勢 및 遺傳力

Heterosis and heritability of stay-green characters in maize

High heterosis was expressed in the days from silking to ear leaf senescence(DELS) of F₁ and even in that of F₂ population with Hi39/KS75. In the number of fresh leaf, fresh leaf area and chlorophyll content, highly positive heterosis was observed in F₁ but negative heterosis in F₂ population except Hi39/KS75. Inbreeding depression in the number of fresh leaf, fresh leaf area and chlorophyll content appeared remarkably with the progress of growth especially from 37 to 52 days after silking(DAS) in April 23 planting, but Hi39/KS75 had low inbreeding depression in DELS compared to other two F₂ populations. Among the characters related to stay-green, the number of fresh leaf showed the highest heritability in the crosses with three inbreds Ga209, Hi39 and KS75. The other characters except the days to maturity also exhibited relatively high heritability. Hi39/KS75 showed very high heritability irrespective of planting dates. The stay-green score was found to be significantly correlated with the number of fresh leaf, fresh leaf area and chlorophyll content at the DAS 52. A multiple regression analysis with F₂ population revealed that the number of fresh leaf was much accountable for the variation in DELS and stay-green score, but less accountable in later growing stage.