ISHS Acta Horticulturae 403: International Symposium on Cultivar Improvement of Horticultural Crops. Part 2: Fruit Crops
STUDIES ON THE INHERITANCE AND SELECTION OF SWEETNESS AND ACIDITY OF APPLES |
| Authors: | L. Baojiang, L. Guiyong, J. Shixi |
| Keywords: | Malus, Apple, Inheritance, Selection, Sweetness, Acidity |
| Abstract:
The inheritance and selection of sweetness and acidity in apple fruits were studied in 62 cultivated varieties and 106 seedlings of 4 combinations. The results indicated that fruit acidity appears to be jointly governed by two genetic model, a single major gene and certain multiple genes. The genetic effect of the major gene (Ma-ma) is incomplete dominance. The homozygous dominant, heterozygote, and homozygous recessive show high acid, subacid and lowacid phenotypes respectively. The effect of the multiple genes on fruit acidity is so great that it can cancel the effect of the major gene and make progenies drift off from the typical segregation. The fruit sweetness is governed by multiple genes that show additive and non-additive genetic effect, and the segregation of the soluble solids, total sugar and reducing sugar contents of hybrids all show continuous variance tending to normal distribution. The effect of fruit acid content on selection is much greater than that of sugar. Subacid posterity has remarkable selection preponderance. The effect of sugar content is relatively smaller, but selection tends to retain subsugar and highsugar, and eliminates lowsugar posterity. In crossbreeding, the cross between subacid varieties of the major gene homozygous dominant themselves, and between them and subacid varieties of the heterozygote can increase the ratio of selective preponderance in progenies and raise the efficiency of apple breeding. | |
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