Abstract:

To investigate the genetic mechanism of multiple male paternal effect in rice population breeding, this study established a hybrid population using a two-line sterile line of rice, Hai S1, and four rice varieties. The main agronomic traits and coefficient of variation in different generations of the population were compared and analyzed. The results revealed that the variation coefficients for panicle number per plant and sterile plant rate in the separated generation population constructed using the rice population breeding were above 32%, indicating significant differences. The multiple male paternal hybrid exhibited more diverse variation types for key yield factors such as panicle number per plant, grain number per spike, and 1 000-grain weight compared with the single-male hybrid. This diversity wais beneficial for enriching genetic diversity related to rice yield traits and increasing opportunities for breeding selection. Sterile plants were isolated from different generations of the hybrid offspring constructed from light-thermo-sensitive sterile lines of rice. multiple male paternal rate of the hybrid offspring was over 10%, with the variation coefficient of the sterility rate being greater in the multiple male paternal hybrid offspring F₃ than in the single paternal hybrid offspring F₃. By utilizing male paternal hybrid progeny for multi-generation self-crossing and outcross mixing with continuously combining random mating populations and adding new parent germplasm at any time, it is possible to expand the genetic base. This approach leads to extremely rich and diverse isolated types among offspring which facilitates continuous innovation in rice germplasm resources.

Key words: rice, population breeding, separated generation, agronomic traits, variation coefficient