Abstract: Inheritance of some characters including self-compatibility, the rate of fertile flowers, average fruit weight, and sweet or bitter kernel were studied with 5-6 years old seedlings of F1 progenies from Katy × Xinshiji, Katy × Hongfeng, Katy × Taianshuixing and Taianshuixing × Katy. The results were as follows: Firstly, the S-locus of Katy was heterozygous, and self-compatibility was dominant to self-incompatibility. Secondly, a very extensive segregation in self-pollinated fruiting rate, fertile flower rate and average fruit weight was observed in the F1 populations, and averages of these traits were lower than that of mid-parent means. Therefore, these traits were confirmed to be quantitative. But significant differences were found in coefficient of variation(CV) and broad-sense heritability (H2) of the three characters: CV and H2 of self-pollinated fruiting rate were both greatest, with the variation mainly resulted from inheritance, and high inheritance potential; H2 of fertile flower rate was the least and its variation was less from inheritance; CV of average fruit weight was the least and its inheritance potential is small. Thirdly, the ratios of sweet to bitter kernel of F1 progenies in positive and reverse crosses between Katy and Taianshuixing were 18∶16 and 13∶12, and were both in agreement with a 1∶1 segregation by χ2 test, which demonstrated that the bitter kernel character of Katy was heterozygous.

Key words: Apricot, F1 progeny, Characters, Heredity and variability