Studies on chlorophyll mutants in diploid wheat induced by radiation

T. FUJII

National Institute of Genetics, Misima, Japan

Further studies on several mutant strains of Triticum monococcum var. flavescens induced by X-rays, were made.

The mutant strains "chlorina" (light green leaves) and "basi-viridis II" (base of leaves yellowish green) were crossed in 1955. All the F₁ plants from this cross were morphologically normal, and showed high germinating capacity and high seed fertility. In the F₂ generation, chlorina and basi-viridis II were found to be controlled independently by a recessive gene each, and a segregation according to the dihybrid ratio was observed. The chlorophyll content in both parents amounted to about 50% of that of the normal plants, but when basi-viridis II was illuminated by fluorescent lamps (about 4,000 luxes) in the dark phytotron (20C), this mutant gradually recovered the green coloring and its chlorophyll content reached that of the normal plants, while in the chlorina mutant such a marked recovery of chlorophyll was not found. The chlorophyll content of the double-recessive plants grown in the field was about 20% of the normal and a high degree of mortality was observed. When these plants were grown in the phytotron, their leaves gradually became light green, and their chlorophyll content was restored to the chlorina level but further recovery did not occur. It is possible that the chlorina gene is epistatic over the basi-viridis II gene.

(Received Nov. 6, 1957)