Site and planting date effects on taro growth: Comparison with aroid model predictions

Taro [ Colocasia esculenta (L.) Schott cv. Bun‐long] is a tropical root crop with the potential to be grown commercially on former sugarcane ( Saccharum officinarum L.) lands in Hawaii. To determine the effects of varying environmental conditions on crop production and to validate an aroid simulation model developed earlier, taro was grown under rainfed conditions at two sites that differed in elevation (90 and 335 m) on Hawaii island and at four planting dates (Winter, Spring, Summer, and Fall) on 27 February, 28 May, 27 August, and 24 November 1992. Biomass harvests were conducted at bimonthly intervals. Using weather, soil, cultivar, and management practices in this field trial, the aroid crop simulation model predicted dry weight of plant components, leaf area index (LAI), and time to harvest maturity defined as leaf stage. Fresh and dry weights of corms increased linearly from 1 to 13 months after planting (MAP), indicating continuous partitioning to the storage organ. The increase in corm fresh weight was significantly greater for Spring + Summer plantings compared with Fall + Winter plantings, primarily due to lower incidence of corm rot. Due to its indeterminant growth, taro can be harvested between 6 and 13 MAP, depending on incidence of pests and soil and weather conditions that could cause early maturation. The aroid model simulated well the maximum LAI; however, it underestimated both potential dry corm yield and length of time to harvest maturity, indicating that further development of this aroid simulation model is needed.