Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2003
Publication Date: 5/16/2005
Citation: Kiru, S., Makovskaya, S., Bamberg, J.B. 2005. New sources of resistance to race ro1 golden nematode (g. rostochiensis woll.) among reputed duplicate germplasm accessions of solanum tuberosum L. ssp. andigena (Juz. et Buk.) Hawkes in the VIR (Russian) and US Potato Genebanks. Genetic Resources and Crop Evolution. 52:145-149. Interpretive Summary: Several genebanks around the world keep wild and cultivated relatives of potato for use by breeders and other scientists. The genebank in the USA (USPG) and Russia (VIR) have many items that are reputed duplicates among their collections. This means that samples from a single original seedlot were sent to both genebanks many years ago, and subsequently multiplied independently at both locations. An important question is whether reputed duplicates are genetically equal. Previous tests showed significant DNA-based differences. We now have tested the VIR sample of 115 duplicates for resistance to nematodes, a very serious pest of the potato crop. About 8 percent of these were highly resistant, and their offspring showed that the resistance is easily transmitted. This work is important in two ways: It has revealed a much broader resource of extreme nematode resistance than previously recognized. It also sets the stage for testing whether the reputed duplicate samples in the two genebanks really do have equal levels of nematode resistance. Thus, this research not only broadens the choice of parents available for resistance breeding, but identifies model materials for future research testing the parity of PCN resistance among reputed duplicate samples in the two genebanks.
Technical Abstract: The cultivated species Solanum tuberosum ssp. andigenum (i.e., andigena per nomenclature used at the US Potato Genebank, USPG) is well known as a rich source of valuable traits for potato breeding, especially for resistance to diseases and pests. The Potato cyst nematode, Globodera rostochiensis Woll., is considered to be one of today's most serious hindrances to potato production in Europe and North America. Thus, the breeding of new cultivars that have resistance to PCN is of great importance. The USPG (USA) and VIR (Russian) potato genebanks, as well as others, maintain many samples of primitive cultivated and wild potato species originating from Latin America. Many of these samples are assumed to be genetically duplicate because the material in both genebanks came from the same original source. A joint investigation of new genotypes of ssp. andigenum forms resistant to PCN was carried out on samples of andigenum at VIR with reputed duplicate samples at USPG. After careful screening, 14 samples which possessed resistance to PCN were identified. A high level of this resistance was transmitted to sexual progeny at a high frequency for all of the selections. Eleven of the accessions found to be resistant have reputed duplicates in USPG that were not previously known to be resistant. Thus, this research not only broadens the choice of parents available for resistance breeding, but identifies model materials for future research testing the parity of PCN resistance among reputed duplicate samples in the two genebanks.