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We investigated the effects of maternal and paternal parentage, and ovule position in a pod on seed development, weight, and progeny performance using an annual crop commonly called cowpea (Vigna unguiculata L.). The experiment was conducted in a greenhouse. Nine maternal parents were randomly selected, and 3 individuals were chosen as paternal parents based on the male fitness components. Five types of hand-pollination were attempted on each flower of the maternal plants to evaluate the influence of paternal identity. Independent variables such as parentage and ovule position affected the pattern of seed development. Ovules in the middle position of the pod exhibited a much higher probability of seed maturation than those at the stylar and basal positions, confirming the position effect. These independent variables also appeared to exert a significant effect on seed weight, although it was not possible to evaluate the relative importance of those variables due to significant interaction between parents. Mixed pollination tended to yield heavier seeds than other paternal parents. Ovules in the middle and basal end positions produced heavier seeds than those at the stylar and regardless of maternal and paternal parentage. Seed weight was independent of all measurements of progeny performance. At week 2 after germination significant paternal effects were found to be mediated through the ovule position in a pod. In particular, the progeny derived from self-pollination performed worse than the progeny from other paternal parentage. The progeny performance at week 4 after germination was affected by maternal parents independently of seed weight. These results show that paternal and maternal effects were quite consistent from the seed development to early growth of the progeny. Consequently, maternal and paternal effects on seed development and weight, and progeny performance may reflect, at least to some extent, genetic contribution of both parents. If so, it is possible for sexual selection on maternal and paternal function to generate the evolution of reproductive traits related to seed production.
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