Segregation of induced chlorophyll mutants in rice

Segregation frequencies of randomly selected chlorophyll mutants, derived from mutagen-treated population of a few rice varieties, were studied and observed to vary from 15⋅0 to 26⋅4%. A number of mutants showed significantly lower frequency than the expected Mendelian proportion of 25⋅0%. The causes of deviation from the expected ratio were investigated by a comparison of germination frequencies and fertilities of two genotypes—hetero-zygotes for chorophyll mutant genes and wild-type homozygotes. In no case matching or larger difference in fertility corresponding to the deficit of the mutants, which deviated significantly from the expected ratio, was observed. For most of the mutants, deficits in the segregation frequency was due to reduced viability of mutant seeds as evident from reduction in germination percentage.