Differential expression of the genetic variance in F2 populations of reciprocal crosses of artichoke

To perform artificial selection, the phenotypic trait of interest is measured on a population and those individuals with the extreme phenotypic values are bred to produce the next generation. Several breeders have recognized reciprocal effects as one source of genetic variability. The objective of this paper was to determine the gene actions, heterosis, and genetic variance present in reciprocal F2 populations obtained by combining divergent artichoke cultivars. Days to first harvest, number of head per plant, weight of the main head, total yield and marketable yield per plant and the length-diameter ratio of main head were evaluated. For precocity and length-diameter ratio, the means value of F1 generations were significantly different. The intermediate values between parents for precocity and length-diameter ratio indicate the presence of additive gene action, while for weight of the main head, total and marketable yield dominance effects were detected. For these traits the absolute mean parent heterosis is important but for marketable yield only the best parent heterosis is expressed (13.1%). Fi reciprocal crosses were not significantly different in any case however, for the reciprocals F2 all the comparisons indicate unexpected differences between them. The higher genetic variance developed in reciprocal F2 facilitated the selection.