Partitioning of Dry Matter in Tanier (Xanthosoma spp.) Irrigated with Fractions of Evapotranspiration

Abstract

The accumulation and partitioning of dry matter was determined in tanier plants irrigated with fractions of the water lost through evapotranspiration (WLET) in an effort to establish growth analysis data from which a tanier growth (simulation model could be developed. The irrigation regimes were based on Class A pan factors ranging from 0·33 to 1·32 with increments of 0·33. Tanier plants were planted in the field and harvested for biomass production about every 6 weeks during the growing season. At each harvest, plants were separated into various plant parts, and their dry matter content was determined. The first 90 d after planting (DAP) were characterized by low rates of dry matter accumulation, with only leaves and petioles showing substantial growth. A grand growth period followed in which leaves, petioles, and roots rapidly accumulated dry matter until 278 DAP. During this period, plants that received 0·99 and 1·32 WLET exhibited similar total dry matter content, and this was significantly greater than in plants supplied with 0·33 and 0·66 WLET. Cormel dry matter content peaked at 29% of total plant dry matter by 322 DAP in plants replenished with 1·32 WLET. Partitioning of dry matter to cormels in other treatments was significantly reduced. Partitioning of dry matter to corms increased linearly throughout the growing season in all treatments. Dry matter partitioning to suckers and the number of suckers formed from plants replenished with 0·33 and 0·66 WLET was greater than in the more irrigated treatments.