Studies on the classification and the geographical distribution of the barley varieties. : IV. Linkage relation and the origin of the uzu or semibrachytic character.

Abstract

In view of the importance of the "uzu" or semi-brachytic habit of growth for the breeding, the cultivation as well as for the genetics of the Japanese barley, the linkage relation and the geographical distribution of the gene for this character were investigated, the summarized results of which were presented in this report. 1. It was shown that the gene pair for normal versus uzu was in herited independently of gene pairs as follows: Vv, Alal located in linkage group I, Bb in group II, Ll. Nn, Lklk in group III, Blbl in group IV, Rr, Ss, Fsfs in group V, and also Fcfc, Ycyc in group VII (the data was omitted) 2. Linkage relations between Uzuz and two gene pairs for chlorophyll denciencies, Acac and Anan, both of which had been known to be located in group VI, were shown in Table 1 and 2, and the gene arrangement on the VI chromosome in barley inferred was given in Fig.1. 3. Cultivated area of the uzu barley in Japan had been enlarged by 5.1 percent during 13 years from 1932 to 1945; it occupies 80 percent of the whole barley acreage in Japan at Present. 4. Geographical distribution of the normal and the uzu barley in Korea in 1940 were investigated, which was shown in Table 3. In spite of the fact that the uzu barley covered as large as about one third of the whole barley acreage in Korea at present, it was obviously known that this form of barley was not indigenous to this country, but had been introduced from Japan since its annexation to Japan. 5. The uzu form of barley is seldom found in the other regions except Japan and Korea. Based on the informations thus obtained, it was reasonably suspected that the uzu or semi-brachytic form of barley had originated by means of gene mutation from a certain normal variety in Japan, host probably in the southern part of it.