II. 46 An earliness gene involved in Chinese native cultivars.
S. Yasuda. The Ohara Institute for Agricultural Biology, Okayama University, Kurashiki 710, JAPAN.
Among the barley collections, made by Dr. R. Takahashi from China in 1944, 10 or more varieties mostly originated from the lower basin of Tangtze River are found to be not only very early in heading time, but also rather shorter for ripening period from heading to maturity. Six of them, Pao-anchenl, Pai-sha-pu 1, Muchih-gang 3, Tayeh 8, Hsin-wuke 1 and Yang-sin 2, were subjected to genetic analysis for the earliness. When sown in fall in Kurashiki, all of the F1 populations from their diallel crosses and some of their F2 progenies headed simultaneously without exception. On the other hand, in the F2's from the crosses of these very early varieties with some later tester stocks including Col-orange, segregation of early and late type plants occurred in a 1:3 ratio, indicating a single recessive inheritance of early character.
Linkage data, given in Table 1, clearly show that the gene for earliness and K for hooded awn in linkage with about 17 to 24 recombination percentages. From the results alone obtained it is suggested that the recessive genes for early heading in these Chinese native cultivars may be identical. If so, this earliness gene will be named ea,,c, tentatively. It is noted also that the gene ea,,c was found to be independent of n(l), v(2), B(5), o(6) and s and r(7), respectively.
