EFFECT OF NITROGEN, MULCH AND GIBBERELLIC ACID ON QUALITY OF MULTI-PURPOSE PUMPKIN (Cucurbita moschata Duchesne) FRUITS

Abstract

Emergence of multi-purpose pumpkin (Cucurbita moschata Duchesne) as an African indigenous vegetable is attracting great attention. This is due to its adaptation to a wide range of climates and high-yielding potential. Sub- optimal pre- and post-harvest factors have greatly contributed to low returns to farmers and consumers through poor yields and high postharvest loss of pumpkins. There is therefore need to determine the optimal pre- and post- harvest inputs which will provide nutritious pumpkin fruits to producers and consumers. Determination of the effect of nitrogen fertilizer, mulch and gibberellic acid on the fruit size, flesh thickness and firmness of multipurpose pumpkin would contribute to solving these challenges. A field experiment was thus set up at the Chuka University farm in two seasons between January 2019 and July 2020. It was arranged in split-plots in randomized complete block design replicated three times. Nitrogen (0, 50, 100 and 150 kg/ha CAN, mulch (zero, black-painted and unpainted rice straws) and gibberellic acid (0, 40 and 80 mg/L GA3) were assigned to main, split and sub-plots, respectively. Data values were recorded fortnightly from the fourth week after emergence. Data values were subjected to analysis of variance using the SAS software and means separated using the least significant difference test at P=0.05. Effect of N was significant on fruit size (0.013) during the second season, flesh thickness during the first and second seasons (0.002and 0.040) and fruit firmness of 0.02 upper and 0.009 lower during the second season. The 150 kg/ha CAN and black-painted mulch resulted in higher fruit size of 2172 cm2 and 2199 cm2 and flesh thickness of 3.387 cm and 3.856 cm, respectively. The effect of GA3 on fruit size, flesh thickness and firmness was insignificant during both seasons. These results show that 150kg/ha CAN and black-painted mulch would give the best fruit quality, while GA3 may not necessarily result in beneficial returns