|Mojtahedi, H - WSU-IAREC, PROSSER, WA|
|Santo, G - WSU-IAREC, PROSSER, WA|
Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 1999
Publication Date: December 15, 1999
Citation: BROWN, C.R., MOJTAHEDI, H., SANTO, G.S. GENETIC ANALYSS OF RESISTANCE TO RACES 1 AND 2 OF MELOIDOGYNE CHITWOODI DERIVED FROMTHE MEXICAN WILD SPECIES SOLANUM HOUGASII. AMERICAN JOURNAL OF POTATO RESEARCH. 76:365. 1999. Technical Abstract: An accession of Solanum hougasii, a wild tuber-bearing potato species native to Mexico was found to be resistant to races 1 and 2 of Meloidogyne chitwoodi. A resistant selection was selfed and the progeny possessed the same combined resistance uniformly. A selected resistant seedling from the selfed progeny was crossed to cultivated tetraploid potato to form a F1 hybrid, and this was backcrossed to cultivated tetraploid potato to form a BC1 population in which resistance to the two races segregated. Progeny of the BC1 were tested in inoculation experiments with four replicates for each progeny genotype for each race of nematode. Resistance was evaluated on the basis of extracted egg counts from the entire root system of pot grown plants. Considering resistance to each race separately, for race 1, non- host status was exhibited by approximately half of the Bc1. About one third of the progeny showed non-host status to race 2. Egg production among progeny which showed non-host status for both races, was higher with race 2 than with race 1. Analysis of co-segregation established that genetic control for the two races appears to be independently segregating. This provides evidence of an independent genetic control in Solanum spp. for resistance to race 2 of M. chitwoodi. These results contribute to our knowledge base of a series of genes for resistance to M. chitwoodi, identified in Mexican wild species, which may have phylogenetic significance.