Stacking Resistance Genes in Multiparental Interspecific Potato Hybrids to Anticipate Late Blight Outbreaks

Abstract

Stacking (pyramiding) several resistance genes of diverse race specificity in one and the same plant by hybridization provides for high and durable resistance to major diseases, such as potato late blight (LB), especially when breeders combine highly efficient genes for broad-spectrum resistance that are novel to the intruding pathogens. Our collection of potato hybrids manifesting long-lasting LB resistance comprises, as a whole, the germplasm of 26 or 22 Solanum species (as treated by Bukasov and Hawkes, respectively), with up to 8–9 species listed in the pedigree of an individual hybrid. This collection was screened with the markers of ten genes for race-specific resistance to Phytophthora infestans (Rpi genes) initially identified in S. demissum (R1, R2, R3a, R3b, and R8), S. bulbocastanum/S. stoloniferum (Rpi-blb1/ Rpi-sto1, Rpi-blb2, Rpi-blb3) and S. venturii (Rpi-vnt1). The hybrids comprised the markers for up to four-six Rpi genes per plant, and the number of markers was significantly related to LB resistance. Nevertheless, a considerable portion of resistance apparently depended on presently insufficiently characterized resistance genes. Bred from these multiparental hybrids, the advanced lines with the stacks of broad-specificity Rpi genes will help anticipate LB outbreaks caused by rapid pathogen evolution and the arrival of new pathogen strains.

Combination Breeding and Marker-Assisted Selection to Develop Late Blight Resistant Potato Cultivars

“…Pyramiding several Rpi genes in one potato plant can greatly enhance its LB resistance [3]. In the progeny of the Sudarynya × 13/11-09 cross, we find several stacks of markers for Rpi genes advantageous for further breeding efforts.…”

“…Sudarynya (released by the Belogorka Research Institute for Agriculture, Leningrad, Russian Federation) was bred from the progeny obtained following the pollination of the 89181/6 clone by a multispecies hybrid 8889/3; the pedigree of the latter lists Solanum tuberosum, S. andigenum, S. demissum, and S. stoloniferum [8]. The 13/11-09 clone of an interspecific hybrid was bred at the Institute of Plant Protection, Leningrad, by selecting from the progeny resulting from the pollination of an F2 plant from S. pinnatisectum k-17464 × Gitte cross with a pollen mixture from hybrids with high LB resistance [3]. According to the long-term field observations, cv.…”

“…DNA concentration was measured with an UV/Vis NanoPhotometer P300 (IMPLEN, Munich, Germany). In the marker analysis, 11 SCAR markers represented nine Rpi genes, namely Rpi-R1, Rpi-R3a, Rpi-R3b, orthologues Rpi-blb1 and Rpi-sto1, orthologues Rpi-R2 and Rpi-blb3, Rpi-blb2 and Rpi-vnt1.3 (Rogozina et al, 2021).…”

“…Cultivated and wild potato accessions from the VIR (N.I. Vavilov Institute of Plant Genetic Resources) were utilized in breeding interspecific hybrids with a pyramid of up to six Rpi genes; when tested under the various soil and climate conditions; many of these hybrids maintained high LB resistance for over a decade [3].…”

Combination Breeding and Marker-Assisted Selection to Develop Late Blight Resistant Potato Cultivars

“…DNA concentration was measured with an UV/Vis NanoPhotometer P300 (IMPLEN, Munich, Germany). In the marker analysis, 11 SCAR markers represented nine Rpi genes, namely Rpi-R1, Rpi-R3a, Rpi-R3b, orthologs Rpi-blb1 and Rpi-sto1, orthologs Rpi-R2 and Rpi-blb3, Rpi-blb2 and Rpi-vnt1.3 (Rogozina et al, 2021). DNA amplification was run in a MJ PTC-200 thermocycler (Bio-Rad, Hercules, CA, USA).…”