| Studies on the induction of mutations by P32
in wheat. III. Chromosomal aberrations in R1 generation, with special reference to the differences of chromosome numbers and of meiotic behaviors Y. WATANABE and K. MUKADE Laboratory of Wheat Rust Resistance Tohoku National Agricultural Experiment Station, Morioka, Japan In the autumn of 1958, dry seeds of a wheat variety, " Aoba-Komugi ", were soaked for two weeks in the solutions of Na2HP32O4 with the doses of 1, 2.5, 5, 7.5 and 10microc per seed, respectively. The experiment was aimed to obtain some knowledges about the cytological effects of P32 on wheat. The percentage of survied plants decreased with the dosage increase; no plant survived at 10microc. But the percentage of chromosomal aberrations per spike increased in direct proportion to the increase of the dosage. The types of the chromosomal aberrations observed at MI of PMC's were translocation, deficiency, non-pairing and their various combinations. It is especially interesting to note that the differences of chromosome numbers and of meiotic behaviors were found not only among florets of a spikelet but also among anthers of a floret. In Table 1 the data are given. Such abnormality of chromosomes in R1 generation might have caused further abnormalities in R2 generation. |