Determination Of Yield Performance and Regeneration Potential of Upland-Grown Arrowroot [Colocasia Esculenta (L.) Schott] In Kenya

Abstract

Despite arrowroot's potential yield, its production in Kenya remains limited, primarily due to the small area available for cultivation and the basic planting techniques employed. The objectives were to determine the optimal planting depth and the most effective GA3 dosage for inducing propagule production. Field and pot experiments were conducted in 2023 and repeated in the 2024 main cropping seasons at the Teaching and Research station, Egerton University, Nakuru County, to evaluate upland-grown arrowroot for varying planting depths on arrowroot tuber yield and yield components. A field experiment was laid out using a randomized complete block design with four replications. The factors included pit depths of 20 cm, 30 cm, 45 cm, and 60 cm. Data collected included shoot parameters, corm yield, and yield components. The planting depths significantly influenced the corm weight per plant: 60 cm (2.67 kg), 45 cm (2.02 kg), 30 cm (1.24 kg), and 20 cm (0.35 kg) yielded the heaviest corms per plant in fresh weight. The depth also affected shoot parameters significantly (p ≤ 0.05). The same trend was maintained for corm yields per hectare: 60 cm (44.63 t ha-1), 45 cm (38.43 t ha-1), 30 cm (29.58 t ha-1), and 20 cm (7.54 t ha-1) were significantly different from each other (p ≤ 0.05). A second pot experiment was conducted in a greenhouse involving two arrowroot cultivars, Girigaca and Kienyeji. The results show that the interaction between the cultivar and GA3 was significantly different for the number of rhizomes, length, and number of nodes per rhizome (p ≤ 0.05). However, the girth of the rhizome was not significantly affected (p ≤ 0.05). Spraying gibberellic acid (GA3) at 750,500, 250, and 100 ppm significantly increased the number of rhizomes produced by Girigaca, with a dose of 750 ppm producing the highest number of rhizomes. The Kienyeji cultivar failed to produce rhizomes but developed suckers. The interaction between the Girigaca cultivar and spraying with distilled water (Control) produced suckers and no rhizomes. Furthermore, a study was conducted to determine the influence of GA3 treatment on the mother plant on the sprouting capacity, plant height, and leaf area of the plantlets produced from rhizomes. The results showed that the interactions between GA3 and the media significantly affected the number of sprouts (p ≤ 0.05), but not the height and leaf area of the plantlets. The outcomes suggest that the rhizomes obtained from arrowroot treated with GA3 influenced the sprouting of rhizome nodal cuttings. The river sand used for sprouting performed better than the sawdust in the initial growth phases, but the latter is a viable alternative. The study demonstrated that planting depth has a significant impact on the yield of upland arrowroot, with deeper pit depths yielding better results for corm weight and overall production. It is recommended that (1) farmers for upland arrowroot production adopt 30 cm wide and 30 to 60 cm deep moisture pits for enhanced yields, (2) gibberellic acid may be sprayed on potted arrowroot plants for rapid, large-scale rhizome production of suckers. But additional research is needed on cultivar maturity and plant density.