title: A simple model for pollen-parent fecundity distributions in bee-pollinated forage legume polycrosses.
abstract: A simple Weibull distribution based empirical model that predicts pollen-parent fecundity distributions based on polycross size alone has been developed in outbred forage legume species for incorporation into quantitative genetic theory. Random mating or panmixis is a fundamental assumption in quantitative genetic theory. Random mating is sometimes thought to occur in actual fact, although a large body of empirical work shows that this is often not the case in nature. Models have been developed to explain many non-random mating phenomena. This paper measured pollen-parent fecundity distributions among outbred perennial forage legume species [autotetraploid alfalfa (Medicago sativa L.), autohexaploid kura clover (Trifolium ambiguum M. Bieb.), and diploid red clover (Trifolium pratense L.)] in ten polycrosses ranging in size (N) from 9 to 94 pollinated with bee pollinators [Bumble Bees (Bombus impatiens Cr.) and leafcutter bees (Megachile rotundata F.)]. A Weibull distribution best fit the observed pollen-parent fecundity distributions. After standardizing data among the 10 polycrosses, a single Weibull distribution-based model was obtained with an R (2) of 0.978. The model is able to predict pollen-parent fecundity distributions based on polycross size alone. The model predicts that the effective polycross size will be approximately 9 % smaller than under random mating (i.e., N e/N ~ 0.91). The model is simple and can easily be incorporated into other models or simulations requiring a pollen-parent fecundity distribution. Further work is needed to determine how widely applicable the model is.
authors.affiliation: U.S. Dairy Forage Research Center, USDA-ARS, Madison, WI, 53706, USA, heathcliffe.riday@ars.usda.gov.
authors.forename: Heathcliffe
authors.initials: H
authors.lastname: Riday
authors.forename: Mark A
authors.initials: MA
authors.lastname: Smith
authors.forename: Michael D
authors.initials: MD
authors.lastname: Peel
mesh_terms: D000818:Animals; D001516:Bees; D003433:Crosses, Genetic; D018744:DNA, Plant / Q000235:genetics; D005298:Fertility / Q000235:genetics*; D000455:Medicago sativa / Q000235:genetics*; D008954:Models, Biological; D000069600:Plant Breeding; D011058:Pollen / Q000235:genetics*; D054817:Pollination; D017422:Sequence Analysis, DNA; D029921:Trifolium / Q000235:genetics*
chemical_list: D018744:DNA, Plant