고추種字의 低溫發芽性에 關한 硏究 Ⅵ. 低溫發芽性의 遺傳分析

Studies on the Germination Ability of Pepper Seeds at Low Temperature Ⅵ. A Genetic Study on Low Temperature Germination

To clarify the inheritance mode of germination ability at low temperature in red pepper, heterosis and combining ability for days to germination and germination coefficient were estimated with a 8-parent diallel crosses, and gene actions for days to germination also done with F₁ generation of the 8-parent diallel crosses and Frond F₂ generations of a 4-parent diallel crosses In addition, the additive and dominance components of variance, heritability and genetic advance for days to germination were estimated with various segregating generations made from the 4-parent diallel crosses. Significant positive heterosis was recorded in days to germination, but significant negative heterosis in germination coefficient. They were about 6 and 8 percent, respectively. Both GCA and SCA were highly significant. and variance of GCA was much larger than that of SCA. “KS2-2” and “Cheonanjaelae” showed significant negative GCA effects on days to germination, whereas they did significant positive GCA effects on germination coefficient. But “Mexico” and “Hoso Yatsu Busa” reversed. On the other hand, Cheonanjaeiae/Mexico, Hoso Yatsu Busa/Mexico, KS2-2/Daehwacho and Saegochu/Putgochu expressed significant SCA effects to the direction of selection for good germination. Vr/Wr graph for days to germination indicated partial dominance for slow germination. Especially “mexico” with slow germination deviated far off the regression line, sugessting if may have a different genetic background. In F₂ populations of most combinations, days to germination was seemingly controlled by polygenes, indicating its normal distribution with one peak., whereas it was controlled by a few major genes in the F₂ populations of Saegochu/ Mexico and Putgochu/ Mexico producing two peaks in their curves. Average heritabilities of days to germination in the F₂ generations were 76.1% and 52.8% in the broad and narrow sense, respectively. Based on heritability in. the narrow sense and F₂ variance, estimated genetic advance was expected to he larger in the crosses of Saegochu/KS2-2 and Putgochu/KS2-2. In the variation components of segregating populations, additive component was higher than dominance one. So it could be possible to make the genes controlling days to germination to be fixed effectively into a homozygouis line. Days to germination in petri-dish was positively correlated with that in soil (r=0.7546**), and the former could substitute for the latter.