ENHANCEMENT OF MULTI-PURPOSE PUMPKIN (Cucurbita moschata Duchesne) YIELDS USING NITROGEN, MULCH AND GIBBERELLIC ACID

Abstract

Pumpkin (Cucurbita moschata Duchesne) acts as a dependable source of food, providing families producing it with various diets and contribution to household food security. Unravelling effects of nitrogen, mulch and gibberellic acid (GA3) on seed, fruit weight and number of multipurpose pumpkin would help maximize economic and medicinal value of pumpkin. Subsequently, an experiment arranged in split-plots in randomized complete block design and replicated three times was conducted at Chuka University in two seasons from January 2019 and July 2020. The main plots were assigned to nitrogen (0, 50, 100 and 150 kg N/ha CAN), split plots to mulch (no mulch, black- painted and unpainted rice straws), while sub-plots to GA3 (0, 40 and 80 mg/L). Each nitrogen rate was applied in equal doses at three weeks seedling post emergence and at the beginning of flowering. The black-painted and unpainted rice straws were placed on plots after land preparation. The GA3 solution was sprayed using a knapsack sprayer, starting with 40 mg/L followed by 80 mg/L. Data collection was done fortnightly from the fourth week after emergence and data values subjected to analysis of variance using the SAS software and means separated using least significant difference at P=0.05. Nitrogen effect was significant on the number of seeds in both seasons. The 150kg N/ha CAN during the first and the second season had the highest number of fruits (3.70≈9250 and 5.63≈14,075 fruits/ha), total fruit weight (11.28≈28,200 kg/ha and 17.61≈44,025 kg/ha) and number of seeds (603.9≈1,509,750 and 575.7≈1,439,250 seeds/ha) respectively. Black painted mulch produced significantly higher total weight and number of fruits during the first season compared to the unpainted and no mulch. It also gave better results in all the treatments. Effect of GA3 was insignificant during both seasons. The results show that 150kg N/ha and black- painted mulch would give yields of economic value to farmers. Use of GA3 may not result in increased number of seeds, total weight and number of pumpkin fruits. Keywords: AIVs, Fruit weight, Fruit set, Plant growth regulators, Pumpkin seeds