PERFORMANCE OF COMMERCIALLY AVAILABLE TRUE POTATO SEED HYBRIDS GROWN FROM TUBERS

Nine commercially available true potato seed (TPS) hybrids were compar ed to four standard clonal cultivars with respect to mean and uniformi ty of foliar characteristics and tuber traits important to the North A merican potato industry. The TPS hybrids were planted using second veg etative generation tubers derived originally from botanical seed. Ten plants from each plot were individually evaluated for plant height, vi ne maturity, early blight symptoms, and verticillium wilt symptoms. Fo llowing harvest, yield was determined and the tubers were rated or mea sured for appearance, shape, specific gravity, and french fry color. T he TPS hybrids had mean values for all tuber and foliar traits, except plant height, that were not significantly different from those of one or more of the cultivars; generally, values for the hybrids fell amid those of the cultivars. Two of the hybrids were taller on average tha n any of the four cultivars. In contrast to the means, trait uniformit y of the TPS hybrids was consistently less than for the cultivars. For all foliar traits, except plant height, the TPS hybrids were substant ially less uniform than the standard cultivars. For specific gravity a nd french fry color, two important processing quality traits, the hybr ids tended to be less uniform than the cultivars; however, the differe nce was much less pronounced than for the foliar traits. Four of the h ybrids were not significantly less uniform than one or more of the cul tivars for french fry color and seven were not less uniform for specif ic gravity. For many market uses, the TPS hybrids appeared to have the tuber yield and quality characteristics needed to compete with standa rd clonally propagated cultivars.