Utilização de parâmetros genéticos na seleção de clones de Pennisetum sp., Zona da Mata Seca de Pernambuco

Abstract

The research was carried out at the Experimental Station of the Agronomic Institute of Pernambuco (IPA), in the city of Itambé, Forest Dry Zone of Pernambuco. It was evaluated eight clones of Pennisetum sp. (Taiwan A-146 2.37, Taiwan A-146 2.27, Taiwan-146 2.114, Merker México MX 6.31, Mott, HV-241, and Elephant B and IRI-381). The objectives were: (a) study the association between morphology and productive traits in Pennisetum sp. clones; (b) identify morphological traits responsible for productivity in Pennisetum sp. clones and (c) study the genotype x environment interaction under forage yield through different methods of adaptability and stability to selection of Pennisetum sp. clones for the Dry Forest Zone of Pernambuco. It was evaluated the canonical correlations and path analysis from the matrix of simple genotypic correlation between morphological and productive traits of the Pennisetum sp. clones. The methods used to study the adaptability and stability were Eberhart and Russell, Wricke, Lins and Binns and the method based on the main components / centroid. The canonical correlations were significant at 1% probability by the chi-square test. The first pair of canonical factors, with correlation of 1.1379, it was associated plants with higher dry matter content to plants with lower leaf area index, lightinterception and leaf angle. The second pair of canonical factors, with correlation of 1.0400, it was associated plants with higher dry matter yield to plants with greater basal tillers density and height, and fewer green leaves per tiller. The results of the pathanalysis showed that the light interception was decisive in the expression of the dry matter content of Pennisetum sp. clones, while the basal tillers density and plant height were responsible for the dry matter yield of these clones. The forage yield was influenced (P < 0.05) by the interaction clones x cuts. The evaluation of Pennisetum sp. clones through different methods of adaptability and stability of the forage yield has increased characterization of the productive performance of clones and provided greater security to the selection. The method based on the main components / centroid allowed greater discrimination on the adaptability of clones. The clone HV-241, despite to the adaptability of the favorable environments, presented less productive stability. The clones of better performance as the adaptability and stability of the forage yield were the Taiwan-146 2.37 and Elephant B, however, is indicated for the first favorable environments and for the second unfavorable environments.