FLOWERING AND TRUE SEED PRODUCTION IN POTATO (SOLANUM-TUBEROSUM L) .1. EFFECTS OF INFLORESCENCE POSITION, NITROGEN TREATMENT, AND HARVEST DATE OF BERRIES

Flowering and true seed production from different order inflorescences in potato (Solanum tuberosum L,) were evaluated in two experiments. The number of flowers per inflorescence, berry set, berry weight, number of seeds per berry and seed weight generally decreased from primary inflorescences to tertiary inflorescences and inflorescences on lateral sterns. The possible relation with carbohydrate distribution is discussed. Quality of the seeds produced from the different orders of inflorescences was a function of seed size; larger seeds showed better germination, emergence and seedling growth. Late harvest of berries increased berry weight and number of seeds per berry from primary inflorescences. Application of additional nitrogen during the flowering period did not affect flowering or differences between inflorescence positions in seed production, but it significantly decreased the number of seeds per berry. The practical implications of these results for true seed production are discussed.