Late blight, caused by the fungus-like oomycete pathogen, Phythophtora infestans, delivers a double economic blow to the region’s farmers. It lowers yields so they have less to live on and sell, and it increases their reliance on expensive chemical fungicides. When weather conditions are favorable to the pathogen, this disease can wipe out a potato crop in a mere few weeks. Late blight is widely recognized as the single worst disease of food crops, causing estimated annual total yield losses of US$ 10 billion worldwide. In Peru alone, losses are estimated at US$ 7 to US$ 25 million per year.
The most sustainable means of controlling the disease is by developing resistance in the potatoes. CIP and its partners have been developing and promoting late blight resistant cultivars for over two decades. Recent advances, such as DNA fingerprinting of the pathogen and the genetic sequencing of the potato, have provided vital information for breeders, who use a complex process of recurrent selection to breed varieties with durable late blight resistance. Amarilis, a variety with high-level resistance, was bred by the Center and first released by Peru’s National Institute of Agricultural Research (INIA) in 1993.
While initial studies showed that its resistance to late blight, excellent culinary attributes, high yield, and short growing period made it an excellent option for farmers, estimating the economic benefits to smallholders from the use of resistant varieties was a complex process. The new report details plot-level information and econometric analysis from 588 plots in the Peruvian Andes’ three main potato-producing areas: Huanuco, La Libertad, and Cajamarca. It shows the impact that Amarilis has had, in terms of reduced fertilizer costs and reliable crop yields, with simulations predicting a 24% reduction in the amount of fungicide use per hectare in some regions, and an average increase on yields of about 9% per hectare for some farmers.
Signs indicate that late blight is becoming ever more virulent, as climate change provides optimal conditions for the disease. In this context, estimates suggest that Amarilis may produce long run benefits to farmers ranging from US$ 3.7-20 million.
The CIP report, titled Assessing the impact of late blight resistant varieties on smallholders’ potato production in the Peruvian Andes, is available at: http://www.cipotato.org/publications/pdf/005381.pdf