Gene Actions and Combining Ability Analysis for Some Seed Characters in Citrullus Mucosospermus (Fursa)

In order to suggest breeding strategies to improve Citrullus mucosospermus (Fursa), 4 × 4 complete diallel cross design involving Bebu, Wlewle small seeds 1 (Wss1), Wlewle small seeds 2 (Wss2) and Wlewle small seeds 3 (Wss3) genotypes was used to assess combining ability and gene actions involved in the inheritance of six seed traits. The F1 direct and reciprocal crosses plus the parental inbred lines coming from these cultivars were grown in a randomized complete block design with three replications. The results indicated the existence of genetic variation between parental lines for all investigated seed traits. Combining ability analysis exhibited the involvement of both additive and non-additive types of gene actions in the expression of all studied traits, suggesting, doing the selection in C. mucosospermus heterogeneous populations for improving these seed traits. Non-additive gene actions were predominant in the inheritance of investigated traits indicating the possibility of the heterosis exploitation or the postponement of selection to later generations for improving genetically these traits. Bebu appeared the best general combiner for Mass of fresh seed, Mass of dry seed, Mass of 100 seeds, seed length and seed width while, Wss1 and Wss2 are the best combiners for percentage of seed integuments. Therefore, parental lines Bebu, Wss1, Wss2 and crosses with high significant specific combining ability effects are proposed for their incorporation in C. mucosospermus breeding programs. The presence of both GCA and SCA effects suggests the use of recurrent reciprocal selection to improve C. mucosospermus seed traits.