Avaliação agroindustrial e genética de clones RB de cana-de-açúcar na zona da Mata de Pernambuco

Abstract

The objective of this work was to evaluate the agronomic and industrial performance of sugarcane genotypes (sacarrum spp.) and the magnitudes of same important genetical parameters in improvement programs of this culture in the sugarcane micro-regions of North Forest and South Coast of Pernambuco. In Brazil, the world’s largest sugarcane producer, there are several improvement programs of this culture, which aim for the obtencion of agroindustrially superior genotypes, and well adapted for each productive region. So, it objectifies the obtencion of varieties which show agricultural and industrial superiority for each exploration area. This search for new genotypes came from the phenomenon of degeneration, which affects the productive capacity of the commercial varieties. By this and other reasons, it’s necessary a constant research and to study new selectioned varieties for the exploration site as well. The cane-plant experimental works were developed during the agricultural year of 2005/2006 at the Central Olho d’Água mills, located at the North Forest of Pernambuco, municipal district of Camutanga (07°24’ S, 35°28’W) and Trapiche mill, located at the South Coast of Pernambuco, municipal district of Sirinhaém (08°35’S, 35°07’W). The adopted experimental delineation was by randomized blocks, with four of them, using sixteen and eighteen genotypes as treatments for experiments conducted in North Forest of Pernambuco and South Coast of Pernambuco, respectively. The experimental unit was represented by five furrows of 8,0 m of length, spaces of 1,0 m between furrows, drawing a total area of 40 m2. There were analyzed, during the twelve months, the craracters stalk number (SN); stalk diameter (SD); stalk weight (SW), internodes number (IN); stalk height (SH); leaf area (LA) and, during fifteen months, the characters tons of cane per hectare (TCH) and tons of pol per hectare (TPH). The clones RB992504, RB992507, RB992510; RB992512 and RB992525 shoed the best values for the characters TCH and TPH in the North Forest. Yet in South Coast, the clones RB992542, RB992551, RB992559 and RB992570 were distinguished for the character TCH. The characters SD, SW, IN, and LA may help in the pre-selection as indicative of TCH. The reason between the coefficient of genetic variation (CVG/CVE) demonstrate favorable condition for selection of the characters SW, SH and LA in North Forest and for IN and SH in the South Coast, indicating success in the phenotypic selection of these characters. The SN is negatively associated with SD, SW, IN, SH and LA. SD, SH and SW, important variables in agricultural revenue of sugarcane, are strongly positive associated between one another.