Assessment of potato breeding progress in the USA over the last century

Potato (Solanum tuberosum subsp. tuberosum) production has increased six-fold (per unit area) in the USA since the 1920s. Direct comparison of potato cultivars released during the past century can help us understand how potato breeding has contributed to these production improvements and to other important traits associated with marketing and utilization. Our objective was to study trends in potato genetic improvement during four subjective breeding periods (BP) (pre-1900 = BP I; 1930 to 1949 = BP II; 1950 to 1969 = BP III; 1970 to present = BP IV), and also to compare performance between and within the three major cultivar types (round-white, long, and red-skinned). In field trials conducted from 1990 to 1992, under best management practices (with scheduled irrigation) in Michigan, the greatest total yield potential was observed in several cultivars released during BP I and II. These cultivars also had late vine maturities. On average, BP II had the greatest marketable yield. Cultivars released in BP III had the lowest total yield, earliest vine maturity, highest scab resistance and most favorable tuber appearance. General trends over periods were for earlier maturity and improved tuber appearance. Round-white cultivars improved for chip-processing ability and dry matter content over breeding periods, while long types increased in percent marketable yield only in BP IV. No trends were observed for scab resistance. When cultivars were grouped according to tuber type, there were no differences in total yield; however, the long types had the lowest marketable yield and the red-skinned types had lowest dry matter content.