ISHS Acta Horticulturae 619: XXVI International Horticultural Congress: Potatoes, Healthy Food for Humanity: International Developments in Breeding, Production, Protection and Utilization
CHARACTERISTICS OF RESISTANCE TO COLUMBIA ROOT-KNOT NEMATODE INTROGRESSED FROM SEVERAL MEXICAN AND NORTH AMERICAN WILD POTATO SPECIES |
| Authors: | C.R. Brown, H. Mojtahedi, G.S. Santo |
| Keywords: | Meloidogyne chitwoodi, Solanum bulbocastanum, Solanum hougasii, Solanum fendleri, gene mapping, resistance genes, germplasm enhancement, breeding |
| Abstract:
The Columbia root-knot nematode (CRN), Meloidogyne chitwoodi is a serious pest of potato in the Pacific Northwest of the US and in the Netherlands. At present, control is achieved by chemical fumigation, a costly practice. Resistance has been found in several wild species endemic to Mexico and the United States. This type of resistance is expressed as lower root infestation rates and a barrier to the successful establishment of a feeding site, giant cell, and reproduction. In resistant roots, the juveniles remain in a vermiform stage. It appears that localized cell death accompanies the resistance reaction, suggesting the functioning of an R-gene. The inheritance and chromosomal location was identified for two sources of resistance, Solanum bulbocastanum, a diploid, and S. hougasii, a hexaploid, as the upper arm of chromosome 11. The localization of resistance to the same chromosome suggests synteny and the possible presence of the primitive B genome of S. bulbocastanum in S. hougasii. Recent surveys have confirmed that two out of 12 plant introduction accessions of S. fendleri tested were 100% resistant to race 1 of CRN. Resistance derived from S. bulbocastanum was introduced into cultivated potato by protoplast fusion, and a traditional backcrossing program has produced advanced breeding clones with root-knot resistance, good horticultural type, acceptable fry color and long tuber shape. | |
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