| Crossing experiments between basi-viridis II
and other mutant strains of T. monococcum T. FUJII National Institute of Genetics, Misima, Japan Crosses between basi-viridis II and basi-viridis I or other mutant strains were carried out in 1957-'58, and double recessive segregants were obtained from each cross. Basi-viridis II and brsi-viridis I recovered the chlorophyll content up to normal when they were placed in the phytotron, but in seedling stage it was only about 50% in comparison with the chlorophyll content of the normals. The chlorophyll content of the double recessive derived from the cross basi-viridis I x II was further decreased and the plants had the appearance of virido-albina mutants. When they were placed in the phytotron, their leaves gradually recovered normal green color as did both parents. On the other hand, early, slender and irregular-ear mutants were crossed to basi-viridis II and double recessive plants were also obtained from these crosses. As to chlorophyll, all double recessive segregants in the seedling stage were similar to the basi-viridis II parent. From those results and similar symptoms exhibited by double recessive plants obtained from crosses between virido-albina and other chlorophyll mutants, it seems that the chlorophyll content of the double recessive shows in seedling stage a further decrease as compared with that of the parents. On the contrary, the chlorophyll content and reoovery in double recessive plants obtained from crosses between chlorophyll mutants and mutants of other kind were quite similar to those of the parental chlorophyll mutant, and they resembled morphologically the other parental mutant. This may be due to the fact that in the crosses between chlorophyll mutants the involved genes have an additive action causing a decrease of chlorophyll content, while the genes for morphological traits have no effect on chlorophyll formation. |