Positioning of cassava cultivars in space management and use of biostimulant

Cassava plays a fundamental role in food, economy, culture and in Brazilian society. Because it is a rustic crop, tolerant to drought and acidic soils, with high adaptive capacity and low production cost, it has become the main source of carbohydrate in much of the world. Due to this and other factors, the presumed work aims to evaluate four cassava genotypes, transplanted in two different densities with the use of a biostimulant for root growth. The present study was carried out in the experimental area of Regional University of Northwest Rio Grande do Sul, in the county of Augusto Pestana – RS, Brazil. The treatments consisted of three cassava cultivars, FEPAGRO-RS 13 Vassourinha, BRS CS01, Iapar - 19 Pioneira with two planting densities, 10 and 20 buds per linear meter, with and without the use of plant biostimulator Sturdy®. The evaluations were carried out throughout the crop cycle, post-harvest and processing. Where the following variables were evaluated: plants emerged at 30, 60 and 90 days, plants that tuberized, starch, plant height, stem diameter, total root length, lignified part of the root, commercial root length, mean root diameter, number of leaves, branching of the stems, roots that tuberized and not tuberized, mass of tuberized roots, fresh mass of commercial tuber with peel, fresh mass of commercial tuber without peel, mass of partially dry peeled tuber. Regarding the density, the one that showed a better performance in the productive character was the density 10 buds per linear meter, which presented the highest averages of the commercial fresh mass without peel. Taking into account the cultivars, the one with the highest fresh mass production was BRS CS01 and Iapar-19 Pioneira. However, FEPAGRO-RS 13 Vassourinha presented a higher percentage of starch. The application of the biostimulant of root growth showed significant effect mainly for the characteristics of productivity. The increase in the number of branches decreases the final productivity of the crop. Another point to consider, the larger the average root diameter, the greater the percentage of starch in the root. By the method of Annicchiarico it can be pointed out that in general the percentage of starch and the dry matter of the roots had a better behavior in density 10 with biostimulant and density 20 with biostimulant.