A GENETIC PERSPECTIVE ON YIELD PLATEAU IN POTATO

Abstract

Average fresh-weight yields of potato vary tremendously by country from 2 to 50 t/ha with a global average of 16.8 t/ha in 2007. There is a need to increase harvestable and marketable yields of potatoes throughout the world, particularly in Asia, Africa and Latin America where increases in food production are required to match population growth, and where new land will not be readily available. Current yields are commonly less than half the potential set by cultivar, length of growing season and temperatures, because of failure to plant clean seed tubers, inadequate application of fertilizers and supply of water, and ineffective control of weeds, pests and diseases. Addressing all these factors would be of immediate benefit to farmers. In contrast, yield increases of more than 1% per annum are unlikely through new cultivars from conventional breeding, particularly when also selecting for stringent quality specifications. Faster progress may come from breeding for better adaptation to local growing seasons and conditions, base broadening, heterosis from crosses between Tuberosum and both Andigena and Phureja potatoes, and genetic modification of carbohydrate metabolism, as well as inbuilt resistance to reduce yield losses from pests and diseases. Increasing yields will remain a challenging objective for breeders during a period of climate change with water use a major issue, the need for heat and drought tolerant cultivars in a number of countries, and new priorities for resistance to pests and diseases.