Genetic linkage of QTLs for late blight resistance and foliage maturity type in six related potato progenies

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

“…In previous studies (Leonards-Schippers et al 1994;Collins et al 1999;Oberhagemann et al 1999;Sandbrink et al 2000;Ghislain et al 2001;Visker et al 2003Visker et al , 2005Bormann et al 2004;Bradshaw et al 2004;Costanzo et al 2005) the most frequently detected QTL for foliage and whole tuber resistance is located on chromosome V, in the neighborhood of the R1 gene. In population 98-21, this region harboured the strongest QTL for length of vegetation period, which also inXuenced leaXet and whole tuber resistance to late blight.…”

“…This thesis is supported by Allefs et al (2005) postulating that late blight resistance is always either "maturity related" or "R gene based". It is still unclear whether the relationship between long vegetation period and late blight resistance results from genuine genetic linkage between functionally unrelated genes or from the pleiotropic eVect of a gene inXuencing both traits (Visker et al 2003(Visker et al , 2005. The most prominent quantitative trait locus (QTL) for plant maturity has been identiWed on potato chromosome V, which overlaps with QTL for late blight resistance (Collins et al 1999;Oberhagemann et al 1999;Bormann et al 2004;Bradshaw et al 2004;Visker et al 2003Visker et al , 2005.…”

The novel, major locus Rpi-phu1 for late blight resistance maps to potato chromosome IX and is not correlated with long vegetation period

“…The few QTLs for vegetation period length tagged in population 97-30 are in accordance with published data. The most important QTL for vegetation period length has been repeatedly identiWed on potato chromosome V in the vicinity of the R1 locus and overlapped with QTL for late blight resistance (Collins et al 1999;Oberhagemann et al 1999;Bormann et al 2004;Bradshaw et al 2004;Visker et al 2003Visker et al , 2005. QTLs for vegetation period length on chromosomes IV, VIII and IX have also been detected in the QTLs tagging experiment of Bormann et al (2004).…”

“…Besides the markers on potato chromosome IX, the population 97-30 was analyzed for 194 sequence-speciWc markers located on the other 11 potato chromosomes, chosen preferentially from map regions previously described as having QTL for length of vegetation period and/or resistance to P. infestans (Gebhardt and Valkonen 2001;Gebhardt 2004;Visker et al 2005). After ampliWcation and CAPS and SSCP analyses, 20 markers were polymorphic in population 97-30.…”

“…The negative correlation between vegetation period length and resistance to P. infestans in potato was already reported in the 1950s (Jwieryjski 1990) and was explained by concomitant introduction of S. demissum genetic factors controlling resistance, both R genes and quantitative resistance loci (QRL), and vegetation period length into the cultivated potato gene pool. Quantitative trait locus (QTL) analysis of late blight resistance and vegetation period length in the same mapping populations could not distinguish whether the correlation between these two traits is due to close genetic linkage between functionally unrelated genes and therefore linkage drag, or to pleiotropic eVects of the same gene underlying both traits (Bormann et al 2004;Collins et al 1999;Oberhagemann et al 1999;Visker et al 2003Visker et al , 2005.…”