ISHS Acta Horticulturae 484: Eucarpia Symposium on Fruit Breeding and Genetics
REPRODUCTIVE BEHAVIOUR AND INCOMPATIBILITY IN ‘STELLA’ SWEET CHERRY |
| Author: | A.R. Granger |
| Keywords: | Prunus avium, isoenzymes, pollen tubes |
| Abstract:
Most sweet cherries express gametophytic self-incompatibility controlled by alleles of the S gene. ‘Stella’ is self-fertile and is heterozygous for the mutant S4' allele. Thus, ‘Stella’ is semi-compatible when selfed. Heterozygotes and S4'S4' homozygotes were expected to segregate in the ratio 2:1. Glutamate Oxaloacetate Transaminase (GOT) isoenzymes have previously been shown to be linked to the S gene in cherry. ‘Stella’ is heterozygous, bc, for GOT and, after selfing, resultant progeny would be expected to segregate for heterozygous to homozygous genotypes in a ratio of 2:1, with the homozygote being bb or cc, depending on which allele was linked to the S4' allele. Isoenzyme analysis of seedlings from the selfing of ‘Stella’ revealed a deficiency of GOT homozygotes; all the progeny had the heterozygous genotype bc. This indicated that S4'S4' homozygotes had not been formed, suggesting S4' pollen was still being recognised. Controlled pollinations combined with fluorescence microscopy provided evidence that the incompatibility genotype of ‘Stella’ is S4S4' and that ovarian rather than stylar recognition/inhibition of S4' pollen tubes occurred. | |
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