DOES NONRANDOM MATING AMONG WILD RADISH PLANTS OCCUR IN THE FIELD AS WELL AS IN THE GREENHOUSE

We tested whether nonrandom mating can occur across a range of conditions in wild radish by performing experimental crosses on plants grown under three greenhouse and one field regime. Variation in maternal condition among treatments was sufficient to alter components of reproduction. Effects of pollen donor identity on total seed mass per fruit were significant overall and stronger in the greenhouse than the field treatment. Mating was nonrandom in the field and in some, but not all greenhouse treatments. Selective filling of multiply sired fruits tended to occur in all treatments but was most pronounced in the low-water and defoliation treatments as performed in the greenhouse. Our results demonstrate that nonrandom mating is possible in the field, so patterns of nonrandom mating found in previous studies of wild radish are not likely to be artifacts of greenhouse conditions. However, we also discovered that there may be limits to the range of maternal conditions under which these processes occur.