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ABSTRACT We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and (iii) modern cultivars in high-input agriculture(More)
ABSTRACT The population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected from cultivated potatoes and the native wild Solanum spp., S. demissum and S. xendinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and amplified fragment length polymorphism (AFLP) multi-locus(More)
ABSTRACT The central highlands of Mexico should provide an optimal testing ground for evaluating the potential threat of selection for resistance to fungicides in the population of Phytophthora infestans. We evaluated the hypotheses that exposure to the fungicides azoxystrobin, cymoxanil, dimethomorph, fluazinam, mancozeb, metalaxyl, and propamocarb(More)
Growth of 6 potato virus S (PVS)-infected potato clones in tissue culture in temperature regimes alternating between supraoptimal (40°C–45°C) and optimal (25°C) temperatures was compared to incubation of etiolated shoots at constant moderate temperatures (37°C) to obtain virus-free plants by shoot tip culture. Both procedures were effective in obtaining(More)
Toluca Valley, Mexico, is the putative center of origin and diversity forPhytophthora infestans (Mont.) de Bary, the oomycete pathogen responsible for late blight, making it an ideal location for screening potato breeding populations for late blight resistance. Approximately 21,500 progeny from the USDA-ARS, Aberdeen, Idaho potato breeding program were(More)
Ribavirin inhibited a specific step of tobacco mosaic virus (TMV) replication. Time-courses of sensitivity of TMV multiplication in asynchronous and synchronous infections demonstrated that ribavirin inhibited an early function that occurs prior to the period of viral RNA and protein synthesis. In the synchronous infection, ribavirin inhibited the synthesis(More)
A segregating introgression population, established by crossing an accession ofSolanum hougasii from the central highlands of Mexico with two successive recurrent corky ringspot resistant parental lines, was screened againstPhytophthora infestans. Foliage and tuber reactions were compared under natural epidemics of US-8 and US-11P. infestans at Mount(More)
Palisade Russet is a medium-late maturing, lightly russeted potato cultivar notable for its resistance to late blight (Phytophthora infestans) infection of foliage and tuber. Palisade Russet is suitable for processing with low tuber glucose concentrations observed following long-term storage at a temperature as low as 5.6°C with consistently acceptable fry(More)
The effects of four previously reportedin vitro tuber-inducing modified culture media on the potato cultivars Atzimba and Juanita were studied under three illumination regimes. Tuberization from stem segments started 7–18 days after transfer for all the cultivar-light-medium combinations, but this early start was not related to tuber yield. Atzimba(More)
The effect of 25 ppm gibberellic acid (GA3), 7,500 ppm Gapol(R) (0.4% molybdate; 0.42% cobalt; 0.56% tungstate; 2.84% borax; 4 ppm indoleacetic acid; 4 ppm naphthyltalamic acid; and 2 ppm ethylenediaminetetraacetic acid) and of two photoperiods (12 and 18 h daily) on flowering of potato cv Marijke was studied under greenhouse conditions. GA3 specifically(More)