ISHS Acta Horticulturae 465: IV International Peach Symposium
DETECTION OF QTLS CONTROLLING PEACH FRUIT ACIDITY AND SWEETNESS |
| Authors: | E. Dirlewanger, A. Moing, V. Pronier, L. Svanella, A. Guye, R. Monet, C. Rothan |
| Keywords: | Prunus persica, linkage map, RFLP, RAPD, AFLP, quality |
| DOI: | 10.17660/ActaHortic.1998.465.7 |
| Abstract:
Fruit quality is in a large part defined by its composition in sugars and organic acids. An F2 population consisting of 63 plants, issued from a cross between two peach varieties, Ferjalou Jalousia®, a non-acid peach, and Fantasia, an acid nectarine, was analysed two successive years for sugar and organic acid contents and for molecular marker segregation (izoenzyme, RFLP, RAPD, and AFLP). Four fruits per tree were analysed for pH, titratable acidity, soluble solids contents (SSC), acid (quinic, malic and citric acids) and sugar (sucrose, glucose, fructose, sorbitol) contents at maturity. The linkage map was established using the MAPMAKER software (Lod>4, recombination fraction<50) and QTL detection with MAPMAKER/QTL. The map is composed of 12 linkage groups each covering 124, 105, 96, 81, 81, 75, 54, 41, 29, 27, 14 and 2 cM, i.e. 729 cM in total and including 241 markers (4 agronomic characters, 1 isoenzyme, 39 RFLPs, 88 RAPDs and 109 AFLPs). Twenty one additional markers remain independent (3 RFLPs, 12 RAPDs and 6 AFLPs). For each of the fruit components analysed at least one QTL was detected. In two linkage groups, QTLs for nearly all components were present. For pH, quinic acid, sucrose and sorbitol content, all the detected QTLs displayed the same effect as the parental phenotypes. On the contrary, for titratable acidity, SSC, malic and citric acids, glucose and fructose some QTLs displayed the same effect and others the opposite effect. The fraction of the total variation in each trait throughout the population explained by the QTL was very high and could reach 80% for nearly all the characters. For most of the characters analysed, epistasis was observed between QTLs. | |
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