γ-Tocopherol Accumulation and Floral Differentiation of Medicinal Pumpkin (Cucurbita pepo L.) in Response to Plant Growth Regulators

Changes in biochemical and agronomical characteristics were studied in medicinal pumpkin (Cucurbita pepo L.) plants under different treatments with plant growth regulators (PGRs). The seeds were subjected to priming with PGRs before planting and plants unerwent foliar sprays with different solutions of PGRs at 10 day-intervals after flowering. γ-tocopherol (γ-toc) content of grains was found to be increased under gibberellic acid (GA3) treatment. The accumulation of γ-tocopherol in the grains of GA3 treated plants was approximately 19.5 % higher than the control and reached 220.2 mg kg-1 dry pumpkin grains. The number of female flowers per plant was positively affected by PGRs and was 10.1 and 1.89 respectively, in the naphthalene acetic acid (NAA) and GA3 treated plants. A significant efficiency of treatments was observed upon fresh fruit yield. The yield increased from 4831 t ha-1 in the control to 6820 t ha-1 with NAA treatment. Priming treatments increased seedling emergence rate and percent. The highest seedling emergence rate was found in GA3 treated seeds.