Genetic analysis and molecular mapping of fruit-bearing habit locus (Bh1) in eggplant (Solanum melongena L.)

In eggplant, two kinds of fruit-bearing habits can be observed, that is, cluster and solitary. The fruits grown in cluster are small in size but contribute towards yield and productivity. In this investigation, we have studied the genetics of fruit-bearing habit and identified the SSR markers linked to this trait. Pusa Safed Baingan 1 (cluster bearer) and Pusa Hara Baingan 1 (solitary bearer) having contrasting traits were crossed to generate F₁ (20 plants), F₂ (215 plants), B₁ (73 plants) and B₂ (64 plants). Genetic analysis of the trait was carried out using Chi-square test. The segregation of plants in F₂ suggested recessive epistasis with ratio of 9:3:4 (solitary: mixed: cluster) indicating involvement of two genes for controlling the fruit-bearing habit. The parental polymorphic 6 SSR markers were used for genotyping F₂ plants and co-segregated with the fruit-bearing habit (Bh¹) locus in 1:2:1. A linkage map covering 63.86 cm distance was developed, the SSR marker emf11A03 was closest with a distance of 4.37 cm, emk03O04 at 12.5 cm distance, and emf21O06 at 14.5 cm. The physical positions of the SSR markers emb01J19 and emf11A03 flanking Bh¹ gene were located at 4.77 mb position of contig Sme2.5_05721.1 and 5.18 Mb position of contig Sme2.5_00994.1, respectively. The findings in the present study will be helpful in marker-assisted breeding to enhance yield in eggplant.