Row spacing and high density of sweet cassava plants submitted to the application of growth regulator

Abstract

Native to South America and belonging to the Euphorbiaceae family, the economic importance of cassava is currently related to the use of its tuberous roots as human and animal food, as well as in the production of farinha and starch, moving millions of dollars annually. Although its importance, the low Brazilian productivity influenced by the low technology level of this crop is a factor that limits production. Alternatives, as high-density planting systems and smaller spacing between rows and plants, are being used to increase cassava productivity. Even though this system propitiates higher final production, a problem observed is the lower plant yield, which presents smaller and thinner tuberous roots. Hence, the utilization of growth regulators, especially of gibberellin's inhibitors, may be an efficient technology to overcome this limitation in high-density planting systems. The purpose of this study is to evaluate the growth, yield, and quality of tuberous roots of sweet cassava submitted to the application of the growth regulator paclobutrazol in a dense spacing and in a high-plant population in two planting seasons. A Randomized Block Design in a split-plot arrangement was chosen as the experimental design. The plots are represented by five planting arrangements (1: 1.00 x 1.00 m (traditional); 2: 1.00 x 0.50 m; 3: 0.85 x 0.59 m; 4: 0.70 x 0.71m; 5: 0.55 x 0.91 m), while the subplots are represented by the forms of application of the growth regulator paclobutrazol (1: Control, without growth regulator applications; 2: Application 3 months after emergence - MAE; 3: Application 3 and 5 MAE; 4: Application 3, 5 and 7 MAE). In each application form, the growth regulator will be applied via foliar at the dose of 100 g a.i. per hectare, diluted in 200 L ha-1 of water. The phytotechnical analyzes of the vegetative growth and the physical-chemical quality of the tuberous roots harvested will be carried out. The results will be submitted to ANOVA and the means compared by Tukey test at 5% of probability. (AU)