Genetic Analysis on Seed Size of Chieh-qua by Mixture Model of Major Genes and Polygenes

【Objective】Genetic analysis of major gene and polygenes was conducted on the length, width, and quality of Chieh-qua seeds to study the genetic rules of seed size and select high-quality Chieh-qua varieties.【Method】Chieh-qua inbred line J16 (big seed) was used as female parent and 18FJ5 (small seed) as male parent to hybridize, and the length, width and seed quality of F2 generation seeds were determined. What's more, the optimal genetic model and genetic law of each trait were obtained by using the mixed model of main gene+polygene.【Result】The most suitable genetic model for Chieh-qua seed length and width was MX2-ADI-AD, that is, two pairs of additive-dominant-epistatic main genes+additive-dominant polygenes genetic model, with the main gene heritability of 87.07% and 90.79%, respectively, and the polygene heritability of both was 0. The most suitable genetic model for the quality of 30 seeds was MX1-AD-ADI, that is, a pair of additive-dominant major genes+additive-dominant-epistatic polygenes genetic model, with the heritability of major genes and polygenes being 79.96% and 8.73%, respectively.【Conclusion】The major gene heritability of the above traits is far greater than the polygene heritability, and the main gene inheritance is dominant. Therefore, in the process of high-quality breeding of Chieh-qua, we should pay attention to the use of major genes, which can be selected in the early generation.