Abstract
Population samples of seven local strains of the barley variety “Hosogara No. 2” were gathered, and six of them were statistically examined for several agronomic characters at the Nat. Inst. Genet., Misima, in 1952 and 1953. In order to analyse the interactions between strains and localities, a contrasting experiment was concurrently carried out at the Kitami Branch of Hokkaido Agr. Exp. Stat., Kitami.
The results obtained may be summarized as follows.
(1) According to comparative experiments, statistical differences were widely found among the strains (Table 1, 2, 3 and 6), and it was concluded that the original population of “Hosogara No. 2” had contained at the start an abundant genetic variability. Basing on the phenotypic relations, the six strains were classified into three groups, A, C; D; and E, F, G.
(2) It was found that the decline in vigor of plants raised from grains produced at Mishima affected the grain yield (Table 3). Further, the interaction between strains and localities was highly significant regarding grain size (table 6). According to Table 8, among four strains (C, D, E, G), C strain showed an extreme change in grain size under the influence of environment and the reverse was true of D strain.
(3) The range of variation in the date of heading in A strain was 22 days in both years (Fig. 1), and the parent-offspring correlation for this character was very high (0.763**). It was concluded that the striking variation in the date of heading within A strain was governed by polygenes.
Polygenic variability was also found within A and D strains for other characters, such as ear length and ear density (Table 4-a and 5).
(4) In F1 hybrids among strains, heterosis was observed. The F1 hybrid between G and C was excellent in vigor, and also in the hybrid between E and G, which were closely related in their morphological characters, a fairly considerable degree of heterosis was found. These results suggest the presence of concealed genetic differences among these strains.
