二条オオムギにおける千粒重のダイアレル遺伝分析

The inheritance of 1,000-grain weight of two-rowed barley varieties was examined using a reciprocal F1 cross and a half F2 diallel cross among eight parents. The F1 generation was examined in five different ripening conditions i.e., (Ⅰ) control, (Ⅱ) leaf cut, in which all leaves were cut at the heading time, (Ⅲ) Spikelet thinned, in which a quarter of the spikelets were thinned at the heading time, (Ⅳ) dry, in which the plants were grown in a vinyl-film house without irrigation, and (Ⅴ) wet, in which the plants were mist-irrigated every two house in the daytime after the heading to the harvest. The experiment was repeated twice. The F2 populations were grown in the ordinary condition. The average 1,000-grain weight was largest in the dry plot followed by spikelet thinned, control, leaf cut, and wet plots. The 1,000-grain weight was predominantly controlled by the additive genes. The dominance effect was also significant. The large grain weight was controlled by the overdominant genes. Epistasis among the genes controlling the 1,000-grain weight was significant, but the maternal effect was absent. In the F1 diallel, heritability was 0.3~0.6 and 0.2~0.5 in a broad and a narrow sense, respectively. In the F2 diallel, it was 0.9 and 0.6 in a broad and a narrow sense, respectively. In each of the 28 F2 populations, the broad sense heritability was estimated as 0.3~0.8.