Genetic effect of eggplant resistance to bacterial wilt

【Objective】 The genetic rule of bacterial wilt resistance in eggplant was analyzed to provide theoretical support and technical guidance for breeding resistant hybrid combinations，dominant breeding and mining related resistance genes.【Method】 Using 4 eggplant germplasm as parents（Y23，NO21，JA02 and SG19），the combining ability analysis of bacterial wilt resistance in each combination was conducted by Griffing complete diallel crossing method. At the same time，the six generation genetic populations（P₁，P₂，F1，F₂，BC₁P₁ and BC₁P₂）of two cross combinations SG19×Y23 and B1×BC03 were constructed respectively. The combined generation analysis method of major gene+multiple gene for quantitative traits was used to analyze the genetic model of bacterial wilt resistance in each generation.【Result】The general combining ability of resistance to eggplant bacterial wilt was much higher than that of special combining ability，indicating that the resistance was mainly additive effect，followed by non-additive effect，and was less influenced by cytoplasmic genetic inheritance. The generalized heritability was 69.8%，and the narrow heritability was 63.3%，these results indicated that the inheritance of bacterial wilt resistance in eggplant was not only affected by genetic effects，but also by environmental effects. The best cross combinations of resistance to bacterial wilt were Y23×NO21 and NO21×Y23. The resistance of the hybrid combination SG19×Y23 and B1×BC03 was in line with the MX2-ADI-ADI genetic model，that was， it was controlled by two pairs of additive-dominant-epistatic effect major genes+additive-dominant-epistatic effect polygenes. The additive effect was dominant，and the disease susceptibility showed incomplete dominance. The BC₁P₂ and F₂ populations were mainly inherited by major genes，with a heritability rate of 77.112% to 88.417%. The BC₁P₁ population was mainly inherited by polygenes，with a heritability rate of 35.332% to 75.050%. The optimal genetic model estimated by the onset period was consistent with the optimal model estimated by the disease grade distribution.【Conclusion】 In the breeding process of bacterial wilt resistance，attention should be paid to the use of additive effect，as far as possible to select strong bacterial wilt resistance parents for cross breeding；the theory of controlling bacterial wilt resistance with two pairs of major genes+polygenes can be used as the basis for resistance gene mapping to carry out subsequent gene mapping related work to avoid blindness of resistance gene mining.