ISHS Acta Horticulturae 592: V International Peach Symposium
PRUNUS DAVIDIANA AND DERIVED PROGENIES: A VALUABLE MATERIAL FOR FRUIT QUALITY STUDIES |
| Authors: | J. Kervella, M. Foulongne, R. Kraif, T. Pascal, F. Pfeiffer, M. Pradier, M. Génard, B. Quilot, F. Lescourret, M. Reick, A. Moing, C. Renaud, C. Etienne, C. Rothan |
| Keywords: | fruit size, stone size, soluble sugar, organic acid, molecular polymorphism, source-sink relationships, Prunus persica |
| DOI: | 10.17660/ActaHortic.2002.592.14 |
| Abstract:
Since 1987, we have been developing a breeding program using a clone (P1908) of P. davidiana as donor of resistance factors to several pests and diseases. P1908 produces small green fruit with large-stone, bitter taste and low flesh sugar content. To obtain resistant commercial varieties as early as possible, we have studied fruit quality traits on P1908 and P1908-derived progenies. Hybrids derived from P1908 after three generations of crossing by commercial cultivars (P. persica, for instance cv. Summergrand®) were characterized for fruit traits, to identify major unfavorable traits at that stage of the breeding program. Insufficient fruit size was the most widespread defect. Additionally, some genotypes produced large-stoned fruit; others were highly susceptible to bruising or presented low fructose content. Ecophysiological processes possibly responsible for the difference in fruit size between 'Summergrand®', P1908 and 'Summergrand®' x P1908 hybrids were investigated. Small fruit of P1908 and hybrids appeared to be related to a reduced sink strength of the fruit in the second phase of fruit growth. Sink limitation might be due to low cell number of fruit flesh, low flesh to stone ratio, and/or low sugar content of the flesh. Restriction fragment length polymorphism (RFLP) between Summergrand® and P1908 is being investigated using probes derived from candidate genes for fruit quality, i.e. genes identified as possibly involved in fruit growth and development processes. Promising results have been obtained since P1908 and Summergrand® were polymorphic for 5 out of the 6 probes already tested. We now intend to go on studying P1908 differences with peach varieties for fruit quality candidate genes, genotype P1908-derived progenies for polymorphic genes, and phenotype them for fruit traits and relevant ecophysiological processes. We thus hope to be able to better understand the impact of the variation of several genes on ecophysiological and fruit quality traits in order to increase the efficiency of our breeding program. | |
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