Correlation of stylar ribonuclease isoenzymes with incompatibility alleles in apple
Fifty-six cultivars of apple were analysed for stylar ribonucleases; proteins were extracted from styles, separated by non-equilibrium pH gel electrofocusing and stained for activity. Excellent correlation was found between the ribonuclease bands revealed and the 11 known incompatibility, S, alleles, in 14 diploid cultivars genotyped in the classic work of Kobel by monitoring pollen tube growth after test crossing, and in 20 cultivars genotyped, at least partially, by more recent DNA methods. For 12 triploid cultivars studied by Kobel, the correlation was good but not perfect. Two apparent minor electrophoretic variants for S10 were noted and, to distinguish them from each other and also from the electrophoretically similar S3, isoelectric focusing was used. Ten cultivars were genotyped for the first time. In all, 14 ribonuclease bands that may correspond to the ‘new’ S alleles, S12 to S 25, were detected but these alleles should be regarded as provisional until confirmed by pollination tests, especially when the electrophoretic differences were only slight. Analysis of stylar ribonucleases is a convenient method of predicting S alleles in flowering material and thereby investigating incompatibility relationships. The polymorphism of the S locus makes it useful for checking the identity and parentage of cultivars.
Unable to display preview. Download preview PDF.
- Batlle, I., F.H. Alston & K.M. Evans, 1995. The use of the isoenzymic marker gene Got-1 in the recognition of incompatibility S alleles in apple. Theoretical & Applied Genetics 90: 303–306.Google Scholar
- Broothaerts, W., L. Verdoodt, J. Keulemans, G.A. Janssens, & W.F. Broekaert, 1996. The self-incompatibility gene in apple and determination of the S-genotype of apple cultivars by PCR. Acta Horticulturae 423: 103–107.Google Scholar
- Janssens, G.A., I.J. Goderis, W.F. Broekaert & W. Broothaerts, 1995. A molecular method for S-allele identification in apple based on allele-specific PCR. Theoretical & Applied Genetics 91: 691–698.Google Scholar
- Knight, R.L., J.B. Briggs, A.M. Massee & H.M. Tydeman, 1962. The inheritance of resistance to woolly aphid, Eriosoma lanigerum (Hsmnn.), in the apple. Journal of Horticultural Science 37: 207–218.Google Scholar
- Kobel, F., P. Steinegger & J. Anliker, 1939. Weitere Untersuchungen über die Befruchtungsverhältnisse der Apfel-und Birnsorten. Landwirtschaftliches Jahrbuch der Schweiz 53: 160–191.Google Scholar
- Sakurai, K., S.K. Brown & N.F. Weeden, 1997. Determining the self-incompatibility alleles of Japanese apple cultivars. Hort Science 32: 1258–1259.Google Scholar
- Sassa, H., N. Mase, H. Hirano & H. Ikehashi, 1994. Identifi-cation of self-incompatibility-related glycoproteins in styles of apple (Malus × domestica). Theoretical & Applied Genetics 89: 201–205.Google Scholar
- Sassa, H., T. Nishio, Y. Kowyama, H. Hirano, T. Koba & H. Ikehashi, 1996. Self-incompatibility (S) alleles of the Rosaceae encode members of a distinct class of the T2/S ribonuclease superfamily. Molecular & General Genetics 250: 547–557.Google Scholar
- Speigel-Roy, P. & F.H. Alston, 1982. Pollination requirements of new apple cultivars. Journal of Horticultural Science 57: 145–150.Google Scholar
- Tustin, S. & W. Cashmore, 1996. Sibling strife in the orchard. Hort+Research Seasons (18):5–6.Google Scholar