Xenia is the effect of pollen on the development and characteristics of the fruits. To reexplore its importance and consequences for grain production in maize (Zea mays L.), the effect of pollen genotype on kernel weight was studied with five white kernel lines as females and several yellow kernel lines as males in a factorial (5 x 20) and in a diallel (5 x 5) mating design. White single-cross hybrids were also used as females. Cross-fertilization advantage was studied in 1993, 1994, and 1995 by mixing pollen from a male and pollen from a female (i.e., autopollen). When inbred lines were used as females the average increase in kernel weight at maturity, because of cross fertilization, was 13% in 1993, 11% in 1994, and 11.5% in 1995. Female effects were the strongest; however, male and female x male interaction effects were also significant although at the limit of significance because of large environmental variation. These effects were also significant for white kernels, showing that there was a stimulation effect on the filling of kernels from self fertilization by the more active billing of kernels from cross fertilization. With single-cross females, cross-fertilization advantage was about halved. Despite genotype X year interaction, the phenomenon seems sufficiently repeatable with significant correlation among years. Results are interpreted as an early manifestation of heterosis which increases sink strength of kernels from cross fertilization.
