MUTATION BREEDING FOR RESISTANCE TO BLACKSPOT BRUISE AND LOW-TEMPERATURE SWEETENING IN THE POTATO CULTIVAR LEMHI-RUSSET

A mutation breeding method was developed to select clones of Lemhi Rus set that have resistance to blackspot bruise and low temperature sweet ening. Following irradiation with gamma rays from a Cobalt(60) source, over 2000 tuber eye pieces were planted directly to the field and tub ers from the resulting crop were individually evaluated for blackspot bruise potential. Selection for blackspot bruise resistance continued for five clonal cycles. Selection for low temperature sweetening began in the M, and continued for three cycles. Ten clones were selected, e ight with significantly (p = 0.05) better blackspot bruise resistance, and two with increased resistance to low temperature sweetening. The results confirm the possibility for the development of a system to imp rove single selectable quality characteristics in potatoes.