Correlation of yield and specific gravity in a tetraploid potato tuberling population

Abstract

In the fall of 1987 and 1988 true seed from 128 and 83 potato crosses, respectively, were sown in flats in the greenhouses at Beltsville, MD, and approximately 350 seedlings from each cross were transplanted into 7.6 cm pots. The largest tuber from each pot was saved for the field experiment. Tubers from the same family were bulked and shipped to Presque Isle, ME, for spring planting in 50-hill plots. Individual hills of one 50-hill plot from each of 24 randomly selected families were harvested. Within each 50-hill plot, five hills were selected based on horticultural characteristics, such as shape, size, smoothness, and freedom from defects to form the population selected for horticultural characteristics (HC). Specific gravity and yield were recorded for all hills harvested. From the remaining 45 hills, the five highest specific gravity hills were selected to form the population selected for specific gravity (SG). Those hills not selected for either horticultural characteristics or specific gravity formed the unselected population (UP). The average specific gravity for the HC was significandy (P < 0.05) greater than the UP. There was a significant (P < 0.05) negative correlation between yield and specific gravity in the HC and SG. There was no correlation between yield and specific gravity in UP. Selection among this plant material on the basis of horticultural characteristics resulted in a population of significantly (P < 0.05) higher yielding plants whose average specific gravity was significantly (P < 0.05) greater than the UP.