Forage biomass quality of five cultivars of Manihot esculenta Crantz during growth

Abstract

Objective: To evaluate the foliage quality of five cultivars of Manihot esculenta Crantz during the annual growing cycle of the crop in northeastern Argentina.

Materials and Methods: Five cultivars of M. esculenta and four cutting times (February, May, September and December) were evaluated. The experimental design was completely randomized with a 5 x 4 factorial arrangement and three replicas. The experimental plots were 5 x 5 m, with 11 rows and 11 plants per row, spaced 0,5 m apart. Digestibility, crude protein and dry matter were determined from the samples obtained from each cutting.

Results: For all evaluated variables, there was interaction between cultivars and cutting time (p < 0,001). The digestibility of the cultivars was higher than 50,0 %, practically all the productive cycle. In February, the lowest digestibility percentages were recorded for all cultivars, with an average of 47,0 %. In the last two cuts, the average reached 60,0 % digestibility. Crude protein content was above 20,0 %, with variations among cultivars and cutting times. Dry matter content of the genotypes varied with cutting time. Most cultivars had lower values in February and September than in May and December.

Conclusion: The results show remarkable mobility in variables related to nutritional quality of M. esculenta among different cutting dates and cultivars. Digestibility is closely linked to tissue age. Of all the cultivars, Paraguaya Cerro Azul (CV1) showed the lowest digestibility at most cutting dates.