TUBER YIELD OF TRUE POTATO SEED FAMILIES FROM DIFFERENT BREEDING SCHEMES

Economical and environmental conditions in the south of Italy suggest that the direct utilization of TPS [true potato seed] as propagation material for potatoes, could be worth exploring. Thus, it is important to identify the most appropriate breeding scheme to enhance productivity and uniformity of the progeny. For this purpose 44 TPS families deriving from different breeding schemes and emphasizing different levels of heterozygosity were tested for yield at two locations in the U.S.A. and one in Italy. The results indicate the superiority of the 4x progeny from 4 x .times. 2x crosses as a family group, and in the frequency of high yielding individual families in all locations. The 4x .times. 2x family group outyielded the OP progeny group by 45%, 79% and 114% at Hancock, Rhinelander (U.S.A.) and in Italy, respectively.