Genetics of Photoperiod Sensitive Genic Male Sterility of Nongken 58S (Oryza sativa)

SHENG Xiaobang Hunan Agricultural College, Changsha 410128

Double-functioned line;;Heredity;;Photoperiod sensitive geinc male-sterility(PSGM)

It has been demonstrated from the experimental observation and analysis on the heading date and fertility of F_1, F_2 and BF_1 descended from combinations Nong ken 58S (NK58S) / nine japonica varieties by using an indicator of bagged seed setting rate that the photoperiod sensitive genic male-sterility of Nongken58S (PSGM NK58S) is controlled by two pairs of recessive major genes and the interaction of those genes is performed differently from parental varieties. For example, the additive effect is appeared in early-maturing and middle season variety (1: 6: 9), the independent segregation in late maturing variety (1: 3: 3: 9) and the recessive epistasis in NK 58 itself (4: 3: 9). The difference in the interacting pat- terns is somewhat related to the heading date of F_1, F_2 and BF_1 The PSGM NK58S, which might be modified by two set of minor genes called photoperiod and thermoperiod control genes, is expressed in va- rious genetic background. To explain the genetic mechanism of such phenomena, a hypothesis of paralled mutation on the duplicate gene loci was advanced and genetic classification and selection of double-func- tioned line of PSGM slightly response to photoperiod and thermoperiod were discussed.