Using 6 species belonging to 2 subgenera of Glycine, the experiment was carried out to clarify the interspecific differences in the content and amino acid composition of the seed protein. The highest value of seed protein content was found in G. soja. This fact shows the feasibility of breeding soybeans with higher protein content by the interspecific hybridization, G. max × G. soja. Although there are some intersubgeneric differences in the pattern of amino acid composition, it may be difiicult to place our hope on the wild species belonging to the genus Glycine for the breeding of soybeans with higher sulfur-containing amino acid content.
Selective fertilization was examined by using pollen mixture in which pollen from female line and that from one of pollen parent lines, inbred line or F1 were mixed in equal quantities. Discussion was made on the fact that pollen from F1 plant among pollen parent lines fertilized more advantageously in comparison with pollen from its parent lines.
Effects of temperature condition during seed formation on dormancy were examined to establish test condition. Induction of dormancy was evident at 30°C especially from middle to later period of ripening, but it was inadequate at 20°C throughout maturation. Under favorable conditions for dormancy formation, the relative roles of covering layers and embryo in dormancy were analyzed and estimated based on the germination test on seeds from reciprocal crosses.
Estimation of the gene number and the effects for the inheritance of primary leaf size of soybean were studied using six populations, P1, P2, F1, F2, and two backcrosses (P1B1 and P2B2). The two parents were found to be differentiated in this character by two effective factor pairs which seemed to be controlled by the intra- and inter-allelic interaction of genes. The dominance genetic effect was about twice as large as additive effect. Epistasis due to dominance × dominance effects was found. It was also found that the dominance effect of the two genes interacted to reduce the primary leaf area.
This experiment was designed to obtain information on the biological effects of ethylene imine. The ethylene imine sensitivity was considerably modified by various treatment conditions such concentration, duration, temperature, oxygen content and post washing time. Marked varietal difference also was observed in ethylene imine sensitivity.
Distorted segregation, which is observed in many genes of different linkage groups in rice, is expected to be genetically controlled. It is proposed that the distortion of the genes belonging to the eleventh linkage group will be based on differential fertilization of gametes which is suppressed by gametophyte genes.
Many short-culm mutants superior in lodging resistance and plant-type were induced by radiation treatment, but they tended to be accompanied by some undesirable agronomic characteristics. One of the mutants was excellent in ripening date, lodging resistance, yielding capacity, milling quality and plant-type, and was released as a new recommended variety.