A COMPARISON OF SEED SETS IN SELF-, INTRA SPECIFIC AND INTERSPECIFIC POLLINATION OF LILIUM SPECIES BY STIGMATIC AND CUT-STYLE POLLINATION METHODS

Growth and morphology of pollen tubes and formation of seeds were inve stigated in several Lilium species and cultivars after self-, intraspe cific and interspecific pollination by two pollination methods: stigma tic and cut-style pollination. 1. The relative pollen tube length as a percentage of the style length from the stigma to the base of style w as 100 % for 96 to 120 hr after stigmatic pollination between compatib le mating partners; it was significantly less between incompatible par tners because pollen tube growth was retarded. In the latter case, gro wth inhibition was evident 24 hr after pollination. Based on the relat ive tube length, L. longiflorum 'Hinomoto' and 'Georgia' had a stronge r tendency for self-incompatible reaction than did L. x 'Enchantment'. 2. There was a possible relationship between the intensity of the sel f-incompatible reaction and the rate of deformed pollen tubes having b ulbous or rugged tips. The deformed tubes made up 60 to 70% of the pop ulation after self-pollination of L. longiflorum 'Hinomoto' and 'Georg ia'; they were 37% in L. x 'Enchantment' and less than 10% in other co mpatible matings. 3. Viable seeds were obtained in the compatible mati ng by cut-style pollination as well as by stigmatic pollination. The n umber of seeds produced by the former method was significantly smaller , ranging from 10 to 50% of the latter. In the self-incompatible matin g viable seeds were also obtained in L. longiflorum, 'Georgia' and L. x 'Enchantment' by the cut-style pollination but not in L. longiflorum 'Hinomoto'. 4. After self- and intraspecific pollination of L, longif lorum 'Hinomoto' and 'Georgia' by cut-style pollination, pollen tubes were observed by a scanning electron microscopy. Pollen tubes of self- pollinated 'Hinomoto' passed by or stopped in front of the micropyles but did not enter them. In other matings, the pollen tubes entered the micropyles even though some had deformed, flat tips.