*2.3. Yield Components and Other Important Agronomic Traits of BILs and BILF1s*

To assess the distribution pattern of yield-related traits between BILs and BILF1s, we surveyed the yield components of BILs and BILF1s in the paddy field of Shenyang Agricultural University in 2018. The normal distribution and transgressive segregation were observed in all of the traits surveyed in both BIL and BILF1s. These results indicate that all of these agronomic traits were controlled by multiple genes. The plant height of BILF1s mainly ranged from 105 to 120 cm, whereas that of BILs was from 120 to 135 cm. These results indicate that the heterozygous genotype of the F1 plants reduces the plant height, based on the fact that the F1 plants were shorter than Sasanishiki and Habataki (Figure 1A). In addition, the grain number per panicle of BILs ranged from 80 to 180, whereas that of the BILF1s ranged from 130 to 260. These results suggest that the heterozygous genotype of the F1 plants increases the grain number per panicle, which also coincides with the result that the F1 plants have significantly more grains per panicle than Sasanishiki and Habataki (Figure 2). Similar distributions of days to heading, panicle number, and 1000-grain weight were observed in both BILs and BILF1s. However, the variation range of setting rate in BILs was larger than in the BILF1s (Figure 3).

**Figure 3.** The distribution of yield-related traits in BILs and BILs. (**A**–**F**) The distribution of days to heading, number of panicles, plant height, grain number per panicle, setting rate, and 1000-grain weight in BILs and BILF1s.
