title: Studies on the self-incompatibility of Petunia hybrida in excised-style culture. Differences in self-incompatibility reaction among four clones.
abstract: In Petunia clones with different S-alleles, self- or cross-pollinated excised-styles of 5, 10, 15, 20 or 25 mm were incubated on a standard agar medium for 24, 48 or 72 h. The length and number of protruding incompatible pollen tubes were compared with those of compatible ones. Throughout the experimental period, the length and number of incompatible pollen tubes of pollen from the S1S1-clone were always less than those of compatible ones. In pollen from S2S2-, S3S3- and S2S3-clones the incompatible pollen tube growth was barely arrested in 5 and 10 mm excised-styles during the first 24 h of incubation. However, inhibition of incompatible pollen tube growth was strengthened with the increase of both excised-style length and incubation period: this was clearly evident in 15 mm or longer excised-styles incubated for 48 h. Ratios of incompatible to compatible pollen tube length in excised-styles incubated for 72 h, were for S3S3 pollen tubes = 0.28, S1S1=0.48, S2S3 = 0.50, and S2S2 = 0.60, and ratios on tube numbers were S3S3 = 0.01, S1S1 = 0.1, S2S2 = 0.21, and S2S3 = 0.21. These results were in agreement with those of in vivo self-pollination. The incompatibility reaction seemed strongest in S3S3-, weaker in S1S1 - and weakest in S2S2- and S2S{3}-clones, and therefore the intensity of S-allele expression would be S3> S1> S2.
authors.affiliation: Department of Botany, University of Nijmegen, Nijmegen, The Netherlands.
authors.forename: Y
authors.initials: Y
authors.lastname: Niimi
authors.forename: H F
authors.initials: HF
authors.lastname: Linskens