Response of upland taro 'Blanca' to sett size and plant spacing

The white-fleshed tare cultivar Blanca has been traditionally used in the c entral mountainous region of Puerto Rico because of its adaptability to low fertility soils, ability to withstand drought periods under rain-fed condi tions and its acceptability by local consumers. Blanca belongs to the Coloc asia's botanical variety esculenta. Thus, it should be characterized by a l arge main corm and few cormels. In commercial fields, individual plants usu ally average more than 10 suckers, a finding which indicates a low harvest index. The objective of this study was to evaluate the effect of practical combinations of sett size and plant spacing on tare Blanca yield and dry ma tter distribution at harvest. Treatments represented alternatives of practi cal significance in commercial production. Sett sizes were 57 to 114; 170 t o 227; and 284 to 340 g per sett. Spacing was 38.1, 45.7 and 61.0 cm betwee n plants. Plants from the smaller setts have the least dry matter and produ ctivity. Regardless of the sett size, plants grown at 61.0- and at 45.7-cm spacing differed neither in yield nor in dry weight measurements. Reduction of the planting distance to 38.1 cm decreased yield and dry weight. The se tt size and plant spacing combinations used were not effective in reducing the number of suckers per plant nor in improving the dry matter partitionin g into the main corm. Plants averaged 13.8 cormels and had a dry matter par titioning into the main corm of 0.37. The results support the need for the selection of Colocasia esculenta genotypes for improved partitioning into t he commercially important part of the plant.