Abstract
The main objectives in potato breeding are increasing yield abilities and improving resistance to numerous pathogens and pests. Among them, the late blight caused by the Phytophthora infestans oomycete is one of the most destructive potato diseases both in Russia and worldwide. Wild relatives of cultivated potato are traditionally used in breeding as the source of valuable R genes conferring resistance to pathogens. Of particular interest are Mexican wild species because Mexico is the centre of origin and diversity of P. infestans and at the same time, it is the centre of potato species diversity. Mexican wild potato species S. bulbocastanum and S. stoloniferum are an important source of the R genes conferring broad-spec trum resistance against various isolates of P. infestans (Rpi-blb1, Rpi-blb2, Rpi-sto1). Recently these genes have been transferred into cultivated potato gene pool using the cisgene approach. At the same time there is a high probability of finding geno types with the Rpi-sto1 gene (functional homologues of Rpi-blb1) among conventionally bred varieties because for about 40 years S. stoloniferum has been used in breeding as a source of the Rysto and Ry-fsto genes of the extreme resistance to the most important viral pathogen PVY. In this study 188 potato varieties bred in Russia and in near-abroad countries were screened for the presence of six gene-specific markers of the RB/Rpi-blb1 = Rpi-sto1 and Rpi-blb2 genes conferring broad-spectrum resistance against P. infestans, and for the markers linked to the Rysto and Ry-fsto genes conferring extreme resistance to PVY. In addition, a marker for detecting male sterile mitochondrial DNA type gamma derived from S. stoloniferum was used. The genotypes selected through the molecular markers were divided into four groups: (A) 13 PVY resistant varieties carrying diagnostic markers of the Rysto, Ry-fsto genes and having sterile mt-type gamma; (B) four varieties possessing mt-type gamma and not having the markers of the R genes introgressed from S. stoloniferum; (C) eight genotypes carrying five gene-specific markers for the RB/Rpi-blb1/= Rpi-sto1; (D) the rest 166 (86.9 %) varieties not possessing any of the diagnostic markers associated with the S. stoloniferum genetic material. The sequences of the Rpi-sto1- and BLB1 F/R-amplicons were identical in all the genotypes of group ‘C’ and showed respective 99 % and 100 % similarity to the corresponding fragments of the Rpi-sto1 and Rpi-blb1 genes from the GenBank database. Among the genotypes of group ‘C’ various mt-types were detected, and some of them were male fertile.
Highlights
The main objectives in potato breeding are increasing yield abilities and improving resistance to numerous pathogens and pests
The R genes conferring broad-spectrum resistance against various P. infestans isolates have been found in several Mexican species that are highly resistant to late blight but less easy crossable with cultivated potato in comparison with S. demissum, e. g. broad spectrum resistance genes were identified in Mexican diploid species S. bulbocastanum – the RB gene known as Rpi-blb1 (Naess et al, 2000; Song et al, 2003; van der Vossen et al, 2003) and the Rpi-blb2, both encode CC-NB-LRR proteins (Vleeshouwers et al, 2011)
One hundred ninety one genotypes of the analyzed subset were screened using the DNA markers associated with the Rysto, Ry-fsto, RB/Rpi-blb1 = Rpi-sto1 genes and with mt-type gamma originating from S. stoloniferum
Summary
The main objectives in potato breeding are increasing yield abilities and improving resistance to numerous pathogens and pests. M exican wild potato species S. bulbocastanum and S. stoloniferum are an important source of the R genes conferring broad-spectrum resistance against various isolates of P. infestans (Rpi-blb1, Rpi-blb, Rpi-sto). M exican wild potato species S. bulbocastanum and S. stoloniferum are an important source of the R genes conferring broad-spectrum resistance against various isolates of P. infestans (Rpi-blb1, Rpi-blb, Rpi-sto1) These genes have been transferred into cultivated potato gene pool using the cisgene a pproach. Indigenous to Mexico, served as an initial source of late blight resistance genes (named R1 to R11) in potato breeding These R genes conferring race-specific resistance against P. infestans were introgressed from S. demissum into the gene pool of S. tuberosum through interspecific crosses and conventional breeding in the first part of the last century (Malcolmson, Black, 1966). Wang with colleagues (2008) suggested that S. bulbocastanum is one of the progenitors of S. stoloniferum
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
