Genetic Analysis of the Special Peel Color Segregation Ratio Coregulated by Anthocyanin and Chlorophyll Pathway Genes in Eggplant

In the study of eggplant (Solanum melongena L.), a cross between the green peel line 19143 and the white peel line 19147 produced E4957 F1 hybrids with a purple–brown peel. Self-fertilization of the F1 hybrids yielded E4957 F2 offspring with a segregation ratio of 27:9:21:7 among individuals with purple–brown, purple–red, green, and white peel colors, respectively, which was consistent with a genetic model controlled by reciprocal recessive epistasis between D and P, and Gv1 likely acting as a modifying factor. The green peel line 19143 exhibited higher chlorophyll but lower anthocyanin levels than the white peel line 19147, which contained low levels of both pigments, while the E4957 F1 hybrids had elevated levels of both pigments. Two epistatic genes, D and P, associated with anthocyanin synthesis, were mapped on chromosomes 10 and 8, respectively. The putative modifying locus Gf, involved in chlorophyll accumulation in the flesh, was mapped on chromosome 8, and the localization interval was close to the previously reported Gv1 locus associated with chlorophyll synthesis in the peel. DNA markers (InDel22522, InDel5531, InDel-APRR2) were developed to genotype 237 F2 individuals and correlate genotypes with phenotypes. Sequence analysis revealed a 6 bp deletion in the SmMYB1 (D) gene and a large deletion in the SmAPRR2-Like (Gv1) gene in the white peel line 19147, as well as a T to A mutation in the SmANS (P) gene in the green line 19143. This study provided evidence for inheritance between loci involved in anthocyanin and chlorophyll pathways contributing to eggplant peel color variation and provides molecular markers that may facilitate the breeding of eggplant varieties with diverse peel colors.