This study was designed to investigate the effect of casein hydrolysate (CH) on the responses in immature embryo culture of Japanese and Chinese wheat. The addition of CH at 0.5-8 g/1 to callus induction media suppressed direct germination of cultured embryos to a great extent, but did not affect on frequency of callus formation.

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Earliness and lateness of heading time in Japanese rice varieties have been genetically interpreted by the multiple alleles on the Lm locus (YOKOO et al. 1980) and by the combi-nation of the E₁. E₂ and E₃ genes (YAMAGATA et al. 1986). This paper reports the results of allelism test between Lm and E₁. E₂ or E₃. Continuous distributions for heading time were observed in the F2 populations of crosses between a line ER with the earliness gene Lm' and five EG Iines, EGI (Ele2e3), EG2 (e₁E₂e₃), EG3 (e₁e₂E₃), EG4 (E₁E₂e₃) and EG5 (e₁E₂E₃) (Fig. 1-A to E). Their segregation ratios for earliness and lateness suggested that two to three genes controlled these variations

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order to utilize the alien chromosome addition lines of radish with single kale chromo-some (2n = 19) for radish breeding, it was considered that introgression of valuable traits frorn kale to radish might be facilitated through translocation induced by nr-ray irradiation. The transmission rates of the single kale chromosome in the seven alien chromosorne addition lines (a-g types) were relatively low and these 2n=19 Plants showed predominantly the 9n + 11 chromosome pairing configuration at metaphase I (MI) in the pollen mother cells (PMCs), indicating the presence of a rare allosyndesis between the single kale chromosome and radish chromosome complernents (KANEKO et al. 1987, KANEKO et al. 1991). In this article, the possibility of translocation and introgression between radish and kale through the e and b type alien chromosome addition lines (2n = 19) was explored by the application of 1(-ray irradiation for radish im provement.

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In general, cracking formation of rice grains, which is one of the unfavourable grain quality, occurs when rice is subjected to natural weathering in the field far after maturing stage. In the present study, varietal differences of the cracks between indica and japonica rice are examined. In japauica rice, varietal differences of cracks were found to be stable every year, i.e., varieties resistant to cracks always showed lower percentage of cracked grains than varieties susceptible to cracks. A11 of the examined varieties derived from Fujisaka 5 were susceptible to cracks, while all of the varieties derived from a combination Norin 22/Norin 1 were resistant to cracks. Hence the resistance to cracks is obviously inherited.

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Callus formation ability in anther culture of rice (Oryza sativa L.) variety, Koshihikari, was investigated genealogically. First, to ascertain the varietal difference in the quality of callus in anther culture of rice, 31 main varieties in Oita Prefecture were studied. There was a significant varietal differ-ence, and they were divided into good callus formation varieties and poor callus formation varieties. The former formed pale yellow and vigorously growing calli. The latter formed brown and poorly growing calli. These results showed that the quality of callus in anther culture of rice could be characterized by the color and growth of callus.

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The objective of this study is to systematize the information about the genes controlling heading time in rice through gene analysis using seven tester lines (EG Iines, EG1∼EG7: Table 1), which differ from one another in the genotype for three late-heading genes, E₁, E₂ and E₃. In this paper, the third report of the study, a Ponlai (or Horai) variety Taichung 65 and five derivatives which are each isogenic to the variety for one of two early-heading genes, Ef-1 and m-Ef-1, were used as the materials. These six lines (T Iines, Table 1) were crossed each with the seven EG Iines, and analyzed for the allelic relations of Ef-1 and m-Ef-1 to E₁. E₂ and E₃ based on the segregations in the F₂ and F₃ generations.

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