Fitness consequences of mating system, seed weight, and emergence date in a winter annual, Collinsia verna

Abstract

Mating system explained 56% of the variance in seed weight; seed weight explained 51% and mating system explained 38% of the variance in emergence date; and mating system explained 71% and seed weight explained 15% of the variance in fecundity. Outcrossed-seed means differed significantly from selfed-seed means for all traits measured. On average, outcrossed seeds were larger, germinated earlier, had higher percentage emergence, and produced plants that were more fecund than selfed seeds. The coefficient of inbreeding depression increased through time from 0.05 for seed weight to 0.23 for fecundity. Seed weight and emergence date were positively correlated, both phenotypically and genetically, for both mating systems, so genes that increase the value of seed weight also increase the value of emergence date and vice versa. Phenotypically, the positive correlation indicates that larger seeds germinate later. Outcrossed seeds were significantly larger but germinated earlier than selfed seeds, suggesting that mating system has an overriding effect in influencing fitness. -from Author