Yield and combining abilities in Andigena potatoes after six cycles of recurrent phenotypic selection for adaptation to long day conditions

Changes in yielding ability were studied in a population of Andigena which had been subjected to six cycles of selection. Significant increases were detected for percent tuberization, mean yield per hill, mean tuber weight, and average rating for tuber appearance. The earliest improvement in yield was largely the result of improving percentage of tuberization. Later gains came from improving mean tuber weight as well as continued improvement in percentage of tuberization. The largest improvement was observed during the last cycle of selection. Changes in combining ability were studied in twenty test-crosses produced by pollinating fourTuberosum females with bulked pollen from plants within each of five of the sixAndigena cycles. Appreciable gains were observed for total yield, mean tuber weight, and yield of large tubers. The most advanced hybrids outyielded a comparable group of sevenTuberosum ×Tuberosum progenies with regards to total yield, tuber number, and yield of large tubers. Mean tuber weight was similar in both groups. The overall results suggest the potential ofAndigena in the production of inter-group hybrids. The results also indicate that the limits of improvement in theAndigena population have not yet been reached and that the combining ability with Tuberosum should continue to improve.