SELECTION OF POTATO GERMPLASM RESISTANT TO PURPLE TOP PHYTOPLASMA AND LATE BLIGHT IN THE TOLUCA VALLEY OF MEXICO
2010 Annual Report
1a.Objectives (from AD-416)
Select potato germplasm resistant to two pathogens, a leafhopper vectored phytoplasma which causes purple top and an oomycete that incites late blight.
1b.Approach (from AD-416)
Tuber families will be sent to PICTIPAPA from various sources in the the US. These will be planted out in field plots in Metepec, Mexico under the supervision of Hector Lozoya Saldana. Obvservations on foliar damage due to Phytophthora infestans and Purple Top Phytoplasma will be recorded. At harvest, selection will be based on field notes and tuber yield and type. Tubers will be retained during the off-season and re-planted the following growing season. Documents SCA with Universidad Autonoma Chapingo.
A wide genetic diversity of Phytophthora infestans (Mont) De Bary, the potato late blight pathogen, is present in the highlands of central México. Chapingo, in the State of México, is reported to be the second location with the most variation of the oomycete, after the Toluca Valley. In order to assess the genetic resistance of potato clones to P. infestans, in the summer of 2009, one hundred clones each of 25 families (2,500 clones total) from the ARS-USDA Potato Breeding Program at Aberdeen, Idaho, were planted under rainfed conditions at the University of Chapingo Experiment Station, and exposed to natural infection by late blight without fungicides. Susceptible cultivar. Alpha reached complete foliar infection five weeks after the epidemic onset. Six hundred and seventy two genotypes produced by crosses at the USDA/ARS Prosser Station were tested in the field and fifteen were selected for resistance and tuberization. The variety Zafiro showed exceptional resistance in field trials. Duplicates of these genotypes were retained at Prosser and subsequently planted to provide access to these clones in the breeding program.
Oversight of the Specific Cooperative Agreement was carried out by telephone conversations, and sharing of data by email.
This project provides field support for the Main CRIS's objective of screening materials for combined resistance to late blight and purple top phytoplasma.