Browsing by Author "Mwaura, M.M."

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Enhancing Preharvest Physiology of Multi-Purpose Pumpkin Using Combined Nitrogen, Mulch and Gibberellic Acid
(African Journal of Horticultural Science, 2022) Isutsa, D.K.; Mwaura, M.M.
In recent times, it has become apparent that multi-purpose pumpkin (Cucurbita moschata Duch.) is a very important crop since its leaves, fruits and seeds can be eaten as vegetables, snacks and blended dishes to boost household food and nutritional security. However, it is regarded as a low value crop, leading to poor cultivation, comprehension of preharvest physiological behaviour, and maximization of productivity in Kenya. Consequently, a study was conducted to assess the effects of combined nitrogen, mulch and gibberellic acid (GA3) in enhancing its preharvest physiology of pumpkin. Four N rates of 0, 50, 100 and 150 kg N/ha supplied as CAN, three mulch types as none, unpainted, and black-painted rice straw, and three GA3 rates of 0, 40 and 80 mg/L were assessed. The experiment was arranged in split-split plots in randomized complete block design, replicated three times in two seasons, and each plant occupied 2 m x 2 m space. Nitrogen was applied to main plots, mulch to sub-plots, and GA3 to sub-sub plots. Pre-harvest physiological variables measured were stomatal conductance, chlorophyll, photosynthesis, and transpiration. Data values were subjected to analysis of variance using SAS Version 9.3. Separation of significant means was done using the least significant difference test at α = 0.05. Results showed that nitrogen and mulch individually and interactively did not significantly (P > 0.05) affect most pre- harvest physiological parameters. The effect of GA3 was not significant on stomatal conductance and leaf chlorophyll, but it was negative and significant on both photosynthesis and transpiration in season 1 which was drier than season 2. Based on the present results, the influence of combined nitrogen, mulch and GA3 on multi-purpose pumpkin cannot be entirely depicted by analysing preharvest physiology. Adoption and application of treatments that promote desired preharvest physiology of multi-purpose pumpkin is recommended, including 50 kg N/ha to enhance stomatal conductance and leaf chlorophyll, and unpainted rice straws to enhance leaf chlorophyll content and photosynthesis.
PRODUCTION OF MINERAL NUTRIENT-RICH MULTIPURPOSE PUMPKIN LEAFY VEGETABLES USING INTEGRATED NITROGEN, MULCH AND GA3
(2022-04) Isutsa, D.K.; Mwaura, M.M.; ; ;
Understanding the effect of nitrogen, mulch and gibberellic acid on minerals and metabolites in multipurpose pumpkin (Cucurbita moschata Duch) is important since it is a dependable source of food, providing families producing it with various diets that contribute to household food and nutrition security. However, production of the pumpkin using optimal or integrated inputs has not yet been embraced in most African countries, resulting in underrealization of its maximum potential. To respond to this challenge, a split-split plot experiment arranged in randomized complete block design and replicated three times was conducted for two seasons from January 2019 to July 2020. The nitrogen (0, 50, 100 and 150 kg N/ha) was assigned to main plots, mulch (no mulch, black-painted and unpainted rice straws) to sub-plots, and gibberellic acid (GA3) (0 mg/L, 40 mg/L and 80 mg/L) to split-plots. Nitrogen was applied as calcium ammonium nitrate (CAN) in two equal doses for each rate at three weeks postemergence 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 to plants using a 1-L sprayer, starting with 40 mg/L, followed by 80 mg/L, once during the fourth week post-emergence. Data collection was done fortnightly from the fourth week after emergence up to fruit harvest stage. Data values were subjected to analysis of variance using SAS software version 9.3 and means separated using the least significant difference test at α=0.05. All the measured parameters were significantly (P<0.05) different. Highest levels of K and Mg were obtained for 100 kg N/ha. On the other hand, P and beta-carotene were highest where unpainted rice straws were used, while application of 80 mg/L GA3 yielded high amounts of P and K. Results further showed that combined N fertilizer, mulch and GA3 consistently had significant (P<0.05) effects on N, P, K, Mg and beta-carotene (highest 23 ppm was for N1M1GA1). Therefore, sole nitrogen fertilizer, mulch, GA3, and combined rates that promote the desired mineral nutrient and beta-carotene contents in multi-purpose pumpkin leaves should be adopted and applied, depending on the kind. Keywords: Minerals, metabolites, multipurpose pumpkins, leaves, nitrogen, mulch, GA3