ISHS Acta Horticulturae 522: XXV International Horticultural Congress, Part 12: Application of Biotechnology and Molecular Biology and Breeding - General Breeding, Breeding and Evaluation of Temperate Zone Fruits for the Tropics and the Subtropics.
GENETIC CONTROL FOR RESISTANCE TO ROOT-KNOT NEMATODES IN PRUNUS ROOTSTOCKS |
| Authors: | M.J. Rubio-Cabetas, A.C. Lecouls, D. Esmenjaud, G. Salesses |
| Keywords: | Amygdalus, genetic control, Meloidogyne, Prunophora, resistance, root-knot nematodes |
| Abstract:
A rootstock breeding program in progress aims at accumulating major adaptative and pest and disease resistance traits in interspecific crosses among Myrobalan plum, peach and almond. Resistant rootstocks appear to be the best alternative to nematicides for controlling Prunus root-knot nematode (RKN) species of major economic importance, M. arenaria (MA), M. incognita, (MI) and M. javanica (MJ). In the subgenus Amygdalus, different ranges of resistance have been found using the 3 previous RKN and a population from Florida, considered like a new species (M. sp. FL). For example, resistance to MA + MI in Shalil peach (GF-557 rootstock), MA +MI + MJ in Nemaguard and other derived peach rootstocks (Nemared, GxN), have been found. However, all Amygdalus material is host to FL. In the subgenus Prunophora, the two Myrobalan plum clones P.2175, P.1079 are immune to all RKN nematodes. In P.2175 and P.1079, single major dominant genes (Mal and Ma2, respectively) control the resistance to MA, MI, MJ and FL. A third new wide spectrum resistance gene (Ma3) has been evidenced in the Myrobalan plum P.2980 from the intraspecific crosses with the host clone P.16.5 (recessive for Ma genes) and with the resistant clone P.2175 (heterozygous forMal). Besides, the resistance response to all four RKN in the first interspecific hybrids (Myrobalan plum crossed with GF.557 and Nemared) are presented. The results will be discussed in relation to the putative genes involved. Based on marker-assisted selection, the strong and wide-spectrum resistance of Myrobalan plum will be introduced in resistant rootstocks pyramiding the Ma genes and Amygdalus genes. | |
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