| I. RESEARCH NOTES Radiation - induced striping in einkorn wheat and its inheritance S. MATSUMURA National Institute of Genetics, Mishima, Japan Seeds of Triticum monococcum flavescens were exposed to X- and gamma -rays by 60Co, thermal and fast neutrons (14 MeV) and Beta -rays by 32P and 131I -solution. In the treated X1 and later generations white and / or yellow stripes were often observed and their mode of inheritance was studied. The striping was divided into the following types. l) Most of white - or yellow - striping found in X1 was maternally or cytoplasmically inherited and was due to plastid mutation. The first appearance of this type occurred in the X2 generation. 2) In the X2 head progeny segregating albina in a simple Mendelian ratio, white-striped leaves were often observed in a few plants. They might be mostly due to a somatic mutation in a heterozygous plant concerning albina (Aa). 3) Some white stripes which could be distinguished from others by the fine nature of striping occurring in all leaves of a plant were controlled by a mutated recessive gene. 4) Special variegation was found in three X1 - plants. Their progeny contained some white seedlings. The basi - viridis (or virido - albina) seedlings, other than albinas, invariably grew up to be variegated; they were controlled by a mutated recessive gene. Evidence indicated that the recessive basi - viridis gene for variegation, which was stable, stimulated plastids to mutate (irreversibly) from green to white. Plastid "exomutation", or mutation from green to white was affected by environmental factors, such as temperature. This type of variegation was already reported for "Okina" - barley by IMAI (1928). |