Crosses between various X-ray induced recessive mutants in wheat

T. FUJlI

National Institute of Genetics, Misima, Japan

Several mutant strains of Triticum monococcum flavescens, namely chlorina, basiviridis II, virido-albina, slender and irregular-ear were crossed with each other. All of these mutations were in crosses with normals simple recessives. In F₂ dihybrid segregation was observed and double recessive segregants were obtained.

Chlorophyll content of double recessive plants from the cross virido-albina x chlorina was slightly decreased in the seedling stage, compared with virido-albina itself. When they were placed in the phytotron (20C, 80% relative humidity), their leaves gradually turned to light green and increased the chlorophyll content, until its amount was restored to the chlorina level, but a further increase was never observed. Seedlings obtained from the double recessive plants from the cross virido-albina x basi-viridis II had no chlorophyll just like albina and died out a half month after germination, even in the phytotron. Double recessive plants in a cross virido-albina slender or irregular ear were in the seedling stage similar as to chlorophyll to virido-albina itself. When both were placed in the phytotron, their chlorophyll content gradually became restored and about a month later was as that of the normals.

From these experiments it follows that the chlorophyll content of virido-albina could be recovered in the cross combinations with slender and irregular-ear which have a normal chlorophyll content. But the virido-albina gene was hypostatic to the chlorina gene and the same behavior was shown by the double recessive plants between basi-viridis and chlorina (WIS No. 6). Albina-like plants obtained from the cross between viridoalbina and basi-viridis II must have been genetically different from albina mutants but they behaved like the latter.

(Received April 24. 1958)