Evaluation of Spider Plant (Cleome gynandra) Genotypes under Different Nitrogen Fertiliser Applications in Kiambu County

Abstract

Spider plant (Cleome gynandra L.) is among the traditional leafy vegetables whose consumption is increasing in Kenya. However, the limited availability of high-yielding genotypes and suboptimal fertiliser use are major causes of low yield, making it difficult for supply to match demand. New genotypes have been developed perhaps whose performance in Kiambu was unknown as well as their response to nitrogen. The objective of this study is to evaluate growth, yield, and preference of eleven spider plant genotypes as influenced by N application in Kiambu County. Field experiments and surveys were conducted during short and long rainfall seasons in 2011–2012 and 2021–2022 in Ruiru and Juja Sub-Counties to evaluate growth, yield and preference attributes of spider plant genotypes under different N rates and forms. In Ruiru, nine genotypes bred at World Vegetable Centre; IP3, MLSF17, MLSF3, P6, UGSF12, UGSF14, UGSF25, UGSF36, and UGSF9 were evaluated. In Juja, two genotypes, JKUAT and Simlaw, were investigated. Genotypes and N factors were investigated. Measurements were taken to quantify growth and yield in terms of height, number of leaves, and leaf area. Plants were sampled five times at 7-day interval. Farmer and consumer surveys — using questionnaires and key informants interviews (KIIs) — were undertaken to determine farmer and consumer preferences for these genotypes. Growth and yield data were analysed in GENSTAT software, and means separated using LSD at = 0.05, while survey data were analysed in SPSS, and genotypes ranked from 1–9 on performance. In Ruiru, the highest plant yields (36.49 and 95.20g) were recorded for plants supplied with 2.3g N/plant while the lowest (33.37 and 78.60g) were 2.6g N/plant in seasons 1 and 2 respectively. Season 1 had a very low yield compared to season 2, with the highest (34.20–40.27g) harvested for MLSF17, P6, UGSF14, UGSF25 and UGSF36 in season 1, and (84.75–94.00g) for MLSF17, MLSF3, P6 and UGSF9 in season 2. For Juja, the tallest plants (65.42–73.50cm) were manure, DAP+CAN, manure+CAN, manure+NPK, and NPK+CAN in season 1, and (82.74–92.60cm) for manure and manure+CAN in season 2. Interaction of fertilisers and genotypes was not significant in both seasons. Largest number of days to flowering (48.86–51.50 DAS) and (42.55–45.33 DAS) were observed for DAP+CAN and manure+CAN for both seasons respectively. Farmer and consumer surveys revealed that MLSF17, P6, UGSF14, UGSF36 and UGSF9 possess desired traits; medium to tall, high leaf area, and a high number of leaves. Simlaw genotype is highly preferred compared to JKUAT. Based on performance and acceptance, it is recommended that genotypes MLSF17, P6, UGSF14, UGSF36 and UGSF9 undergo onward protocol tests for distinctness- uniqueness-stability (DUS), and national performance trials (NPTs) for their release as new varieties, and farmers grow the Simlaw genotype using 2.3g N/plant in manure form or 2.6g N/plant as CAN. This study findings add a significant contribution to the management and production practices that enhance spider plant yield and achievement of the second Sustainable Development Goal (SDG) by 2030.