2000 Volume 50 Issue 2 Pages 207-219
To study the possible origin of intermediate forms between Petunia axillaris subsp. axillaris and subsp. parodii, reciprocal crosses between typical subsp. axillaris and subsp. parodii were made and F_1, and F_2 progenies were examined for the inheritance of floral morphology. Three characters were chosen to evaluate floral morphology: corolla tube length, corolla limb diameter, and anther distance. We focused on the distance between the anthers of long and medium stamens, a key character distinguishing the two subspecies, which was not examined in detail by previous researchers. The wide range of measured values observed in the F_1 plants suggested a high degree of heterozygosity in the genes determining such floral characters in wild population of P. axillaris, especially in subsp. axillaris. The distribution of the values in the F_1 and F_2 plants was closer to the seed parent when the reciprocal crosses were compared, and the entire ranges of the values were closer to subsp. axillaris, not to subsp. parodii. According to the distribution of tube length and anther distance values, part of the origin of the intermediate forms could be explained by the possibility of crossing between the two subspecies.
