벼 組織培養을 利用한 突然變異誘發 硏究 Ⅱ. 半數體유래 變異體의 出現頻度의 短稈變異體의 遺傳分離

In vitro culture techniques for mutation breeding in rice Ⅱ. Frequency of phenotypic variants from haploid and segregation mode of short culm mutant

This experiment was conducted to broaden the scope of mutation breeding through in vitro culture techniques. Phenotypic variation between A₂ lines derived from rice anther culture (CV, Dashukei 2) and M₂ lines derived from haploid node culture with mutagen, DES(Diethylstilbestrol) 10⁻⁵ Mol, were compared in major agronomic characters. Genetic analysis of a induced variants with stunted culm from haploid node culture with mutagen, DES, was also conduced to clarify the mode of inheritance. This was for the first time confirmed in androgenic somacolonal variants derived from haploid cell culture with mutagen. Although almost of A₂ and M₂ population were nearly same to parental variety, the frequency of lines without within-line segregation was 4.8% in anther-derived A₂ population and 19.2% in haploid node culture-derived M₂ population in phenotypic patterns. The frequency of lines with simple segregation in one or two characters was much greater in M₂ population than A₂ population. It may suggest that extent of androgenic somaclonal variation occurred in vitro process will be increased by supplemented with mutagen. A induced mutants with stunted culm and panicle length, about 87% of culm length and 81% of panicle length compard to parental variety, could be selected for genetic analysis from haploid node culture-derived M₂ population. The segregation of 505 F₂ plants and 76 BC₁F₁ plants from a cross between Dashukei 2 as parental variety and Dashukei 2 M28 with stunted culm presented nearly normal distribution curve and referred to the inheritance of a quantitative character controlled by multiple genes. Molecular evidence for explanation of androgenic somaclonal mutants should be needed in the near future.