Incompatibility reactions during the flowering period of several Petunia clones

The style length at anthesis and the pollen tube length after self and cross pollination in flowers which were produced throughout the flowering period on three clones containing various combinations (S1S2, S2S2, S3S3) of S alleles were measured. An increase in style length as the flowering period progressed was found in S2S2 and S3S3 while no change was observed in S1S2. In S3S3, a decrease in style length was evident very late in the flowering period. Flowering period had little or no effect on the pollen tube length/style length ratio but this ratio was altered markedly by clone and pollination type. Flowering period had little or no effect on the incompatibility reaction expressed by the ratio of incompatible to compatible pollen tube length but this ratio was markedly altered by clone.