Tagging QTLs for late blight resistance and plant maturity from diploid wild relatives in a cultivated potato (Solanum tuberosum) background

Abstract

Phytophthora infestans causes an economically important disease of potato called late blight. The epidemic is controlled chemically but resistant potatoes can become an environment-friendly and Wnancially justiWed alternative solution. The use of diploid Solanum tuberosum derived from European tetraploid cultivars enabled the introgression of novel genes encoding foliage resistance and tuber resistance from other species into the modern cultivated potato gene pool. This study evaluated the resistance of the obtained hybrids, its quality, expression in leaXets and tubers and its relation to the length of vegetation period. We also identiWed genetic loci involved in late blight resistance and the length of vegetation period. A family of 156 individuals segregating for resistance to late blight was assessed by three laboratory methods: detached leaXet, tuber slice and whole tuber test, repeatedly over 5 years. Length of vegetation period was estimated by a Weld test over 2 years. The phenotypic distributions of all traits were close to normal. Using sequence-speciWc PCR markers of known chromosomal position on the potato genetic map, six quantitative trait loci (QTLs) for resistance and length of vegetation period were identiWed. The most signiWcant and robust QTL were located on chromosomes III (explaining 17.3% of variance observed in whole tuber tests), IV (15.5% of variance observed in slice tests), X (15.6% of variance observed in leaXet tests) and V (19.9% of variance observed in length of vegetation period). Genetic characterization of these novel resistance sources can be valuable for potato breeders and the knowledge that the most prominent QTLs for resistance and vegetation period length do not overlap in this material is promising with respect to breeding early potatoes resistant to P. infestans.

Single Nucleotide Polymorphisms in the Allene Oxide Synthase 2 Gene Are Associated With Field Resistance to Late Blight in Populations of Tetraploid Potato Cultivars

“…Few studies have analyzed quantitative trait loci (QTL) for resistance and plant maturity in the same mapping population (Collins et al 1999;Oberhagemann et al 1999;Visker et al 2003;Bormann et al 2004;Bradshaw et al 2004;Sliwka et al 2007). These experiments showed that many QTL for resistance to late blight colocalize with QTL for plant maturity, which explains the phenotypic correlation observed between these traits.…”

Examination of Potential Measures of Vine Maturity in Potato

“…Although high levels of misclassification were observed for all three measures, some were more accurate than others. We found measures of flowering development to be highly inaccurate, even though they are a common component of various maturity screening protocols [2,[4][5][6]. Peroxidase measures were slightly better, but the optimal period of time to assess this trait was variable across locations.…”

“…Flowering is a physiological attribute commonly utilized by potato breeders for evaluating maturity [2,[4][5][6]. Abundant flowering has been correlated with delayed tuber bulking [7].…”

Marker-assisted Breeding for Disease Resistance in Potato

“…However, the TPT marker is being studied in ber-progenies. This marker is located on Chromosome 10 linked to a QTL for resistance in leaflets which accounted for 15.6% of the variance in resistance (Sliwka et al 2007). Based on the results obtained from a t-test, the difference of the means is considered to be statistically significant.…”