The size and weight of kernels of non-waxy and waxy isogenic lines of a variety Taichung 65 (17-time backcrossed) and their F₁ plants were compared under different grain filling conditions in a glasshouse. After the hull (lemma and palea) developed fully In size 13 treatments, i.e, nitrogen top-dressing (two levels), rachls branch thinning (two levels), Ieaf blade cutting (four levels) and shading (five levels), were applied to the plants. Non-waxy and waxy isogenic lines and their F₁ plants were grown m the same pot to mlnlnuze expenmental error, and two pots were employed for each tre-atment

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The dwarf mutant line, Fukel No 71, shows a large varlatron on its culm elongation under different environmental conditions in order to elucidate the essential factors of this character expressron, Fukei No 71 was compared with the semi-dwarf mutant cultivar, Reimei, and the original cultivar of both mutants, Fujiminori, on the mode of culm elongation under different temperature conditions in combination with three different fertilizer treatments, three different temperature treatments were performed from seedling stage to maturity as follows 1) high temperature condition (daytime 30°C-nighttime 25°C), 2) Intermedlate temperature condition (23°C-18°C), and 3) Iow temperature condition (16°C-12°C) With regard to culm elongation, a remarkable dafference between Fukei No 71 and the other two cultivars was observed in the response to temperature in two cultivars, FuJiminori and Reimei, culm elongation was accelarated approxlmately in proportion to an increase in temperature on the contrary, Fukei No 71 was depressed under high rather than moderate temperature condition on the other hand, no particular responses to fertilizer were found in all three lines When Fukei No 71 was exposed to very high temperature (45°C-30°C from the varrous developing stages to maturity, the growth was so much depressed that many plants falled to emerge panlcles completely from flag leaf sheath Under such a very hlgh temperature condition, however, Fujiminori could produce a considerable number of panicles emerged completely from flag leaf sheath, although their headlng dates were slilghtly later than under a greenhous condltron (control) in both lines, the pattern of relative elongatlon of culm internodes varled considerably with different temperature condition, however, Fujiminori could produce a considerable number of panicles emerged completely from flag leaf sheath, although thelr headlng dates were sllghtly later than under a greenhous conditron (control) in both llnes, the pattern of relative elongation of culm internodes varled conslderably with different temperature conditions in general, the upper internodes were more elongated under high temperature condition than under low temperature condition, while the lower ones were more reduced under high temperature condition than under low temperature condition Such an expression pattern tended to be exhibited more intensely in Fukei No 71 than in FuJiminori

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The growth of embryo of Triticu, m monococcum L. was analyzed in detail. The caryopses were collected every two hours. At each time, the growth rate of embryo was calculated for the length and thickness, which showed an undulatory variation. Then the correlogram analysis was applied to the stationary growth rate. It also showed the apparent periodicity. In the next place, the correlation coefficient between the autocorrelogram and the cosine function was calculated as a periodogram. The periodogram showed two significant peaks in the thickness. Though only one peak was significant in the length, the second highest peak in the length existed at the same position as the significant one in the thickness. Furthermore, the other peaks near the significant one in the periodogram are considered to be of no biological meaning, resulted from the finiteness of the number of samples. Therefore, it is concluded that the growth rate of embryo both in the thickness and length are represented by the summation of two cosine functions with periods of 6.06 and 7.72 hr in thickness and 6.00 and 7. 74 hr in length. But the variation of the growth rate at the very early stage did not agree well with the two rhythms. Embryo starts the dual rhythmic growth at the 100-cell stage. This suggests that at the 100-cell stage cells in embryo begin synchronous divisions at two regions which eventually develop into two apical meristems.

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Specific telomeric regions of certain somatic chromosomes in seven accessions of Camellia japonica L. sensu lato were differentially stained by the BSG method. At early somatic prophase, almost all chromosomes in the Camellia accessions studied had C-bands in their telomeric regions. From mid-prophase to mid-metaphase a gradual decrease in C-band number was observed. In order to standardize the data C-bands were recorded at somatic mid-metaphase. Each of the seven accessions of C.japonica L. sensu lato studied here had a characteristic and recognizable C-banded karyotype. In most cases in these accessions the C-bands were found in the telometric regions of the chromosome arms, and C-banded karyotype maintained some heteromorphism. Of those studied here, Cal7tellia japonica L. subsp. lusticana (Honda) Kitamura was quite different from the others.

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The condition for effective single plant selection in early generation is defined.Numerical computations show that the condition is satisfied not only for qualitative characters but also for the continuous characters which are assessed as easily as and are as heritable as heading date and some characters related to plant height and plant type. Early selection is remarkably advantageous for the characters where promising genotypes are highly selectable compared to unpromising ones. This holds even in the presence of a negative but not very close genetic association between these characters and others which are not assessed in early generations. Comparison is made between the two selection systems; the early selection system where plants with promising phenotypes for heritable characters are selected in F₂ generation using a sufficiently large population, and the delayed selection system as the bulk breeding method in Japan, where early populations are generation-advanced, neither plant nor cross selection being carried out until F₄ or later generations. It is shown that a larger chance of success with a given breeding cost (including time and labour) is achieved by a breeding system incorporating early selection.

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There are quite noticeable discrepancies between the linkage groups of Japonica and Indica rices. Many kinds of genes concerning anthocyanin coloration are not identical between the both groups even though the same gene symbols are assigned arbitrarily. It is estimated that the gene system on coloration in the Japonica group is partly different Lrom in the Indica group. In this report, the authors carried out the genic analysis on the coloration using intervarietal crosses between Japonica and Indica rices. Though the gene system on the fundamental coloration in Japonica rice fitted in those crosses studied here without any alteration, a new distribution gene for the coloration was needed for explaining the mode of inheritance on the coloration of plant body. Namely, a single dominant gene, Pin₁ was responsible for the coloration of a part of leaf and stem nodes, and the entire surface of internode under the existence of the high ranking genes of C-A groups. In addition, the causal gene, Pin₁ belonged to the 2 nd linkage group showing the recombination values, 30.9% and 40.O% with Pl and lg, respectively. Although the genes such as Pin₁ showing a complementary effect were reported in Indica group, it was quite difficult to compare their loci with Pin₁ owing to the discrepancies between Japonica and Indica linkage groups.

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A total of 83 paddy rlce varletles and lines were raiscd in the field under natural condition According to MATSUO'S classificaticn (MATSUO 1952) these materlals were classified into three groups hy plant type-plant tyre A 53, plant type B 20, plant type C 10 The lengths of bcth anther and stlgma In each Varrety were measured In 18 spikelots (6 spikelets per panicle, 3 panicles per Variety)at the heading. Significant varietal differences were established for both characters, but correlation coefiicients between them were not significant in all plant types (plant type A: r=0. 210, plant type B: r=0. 214, plant type C: r=0. 441). In plant type A, awnless varieties, most of them recently bred in Japan, possessed anthers and stigmas significantly shorter than those of fully awned ones.

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Three rice varieties differing in yield stability, i. e., Koshihikari (low), Panbira (high) and Taichung Native I (high), were grown under the different combinations of environments consisiting of two levels each of N-fertilizer and solar radiation, or of two levels each of N-fertilizer and temperature. Dry weight and total leaf area per plant and nitrogen content in leaL blades were measured at three stage of plant growth, i. e., active tillering stage, panicle formation stage and heading time. Number and size of stomata and interval of veins on leaf blade at each leaf position were also measured. Following the analysis of variance of each character, ratios of variance for environment to that for error were calculated for each variety. Yield stability and phenotypic plasticity were expressed by the variance ratios of the respective characters.

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