Population genetics of self-incompatibility and developing self-compatible genotypes in niger (<Emphasis Type="Italic">Guizotia abyssinica</Emphasis>)

Two cucumber recombinant inbred lines (RILs) differing in plant habit were crossed and progeny self-pollinated to produce F₃ individuals upon which phenotypic selection was practiced to identify a base population which in turn underwent either two cycles of MAS or random mating without selection (RAN). MAS and RAN were practiced to produce F₄ and F₅ progeny sets. RIL, crossing parents, and F₃–F₅ progeny sets were then evaluated under replicated field conditions for fruit yield and quality (L:D and E:T) to evaluate gain from selection (ΔG). The broad-sense heritability (h ² B) over cycles (C) of selection ranged 0.22–0.45, 0.09–0.20, and 0.11–0.15 for yield, L:D, and E:T, respectively. Although one cycle of PHE selection followed by MAS was effective in conserving the performance of the traits examined during inbreeding, progeny performance during RAN fluctuated (F₄–F₅ generation; C₂). Lack of ΔG during advanced generations (F₄–F₅) of MAS was likely due to allelic fixation and/or optimized epistatic complementation.