GLASSHOUSE-BASED SELECTION TO IDENTIFY AGRONOMICALLY ADAPTED, UNIFORMTRUE POTATO SEED (TPS) PROGENIES

Twenty-five true potato seed progenies and five clonally maintained cu ltivars were grown in a glasshouse. Tubers of each clone of each proge ny were grown in a field experiment. At harvest, one seed tuber was ta ken from each plant and field grown for a second year. After each expe riment, the tubers from every plant were weighed and counted and their colour, shape, form (regularity) and skin finish assessed. Progeny me ans and variances for each character were calculated. There were signi ficant differences between means for each character in all experiments , except mean yield in the glasshouse, variances for each character in both field experiments and tuber number variances and colour variance s in the glasshouse. In general, Pearson's product-moment correlations between glasshouse and field assessments were moderate or poor (r les s than or equal to 0.6) and inconsistent between experiments. Spearman 's rank correlations between glasshouse and field assessments for prog eny means were similar to the linear correlations, while those for var iances were somewhat better. Rank correlation gave more consistent res ults between experiments. Ranking glasshouse means will allow some wor thwhile progeny selection for tuber colour, shape and skin finish. It can be a useful screen for progenies with the highest levels of unifor mity for all characters.