Assessment of Pollen Production, Pollen Viability, Autofertility and Paternal Success in Faba Bean ( <scp> <i>Vicia faba</i> </scp> L.) for Better Exploitation of Grain Yield Heterosis

ABSTRACT In animal‐pollinated plants, pollen dispersal depends on several plant and animal characteristics that can influence the paternal success of a plant. Paternal success affects the genetic contribution of a genotype to the next generation, which is relevant to plant breeding. In faba bean ( Vicia faba L.), with its partially allogamous breeding system, the aim of breeding synthetic cultivars is to achieve equal contributions from the component genotypes, thereby minimizing inbreeding. Because direct assessment of paternity is costly, we investigated whether components of plant fitness such as pollen production and pollen viability could be used as estimates of paternal success. In a field experiment and a caged outdoor pot experiment, a 14 inbred lines and 4 F1 hybrids were evaluated for their pollen production, pollen viability and autofertility, and midparent heterosis in these traits was estimated. We found large variation in pollen production, heterosis for this trait, and higher pollen production in the lower than in the upper inflorescences; hence, the position of the sampled inflorescence on the plant should be reported in studies on pollen production. Pollen viability was high, indicating that fertilization success is not limited by pollen quality. Heterosis for pollen viability was significant only in the field. Autofertility ranged from 0% to 98% with marked heterosis but was not related to pollen production, pollen viability or paternal success. However, pollen production and pollen viability were highly correlated with paternal success. This correlation suggests that in faba bean breeding, data on pollen production and viability can inform the selection of parents with small differences in paternal success, resulting in reduced inbreeding and improved exploitation of grain yield heterosis in synthetic populations.