Interação genótipos x ciclos de colheita em cana-de-açúcar no litoral sul de Pernambuco

Abstract

Brazil is the world leader in sugarcane industry and to be reached this level was necessary investment in research, among them obtaining new varieties that tested in different environments can occur that are more effective in some and not in others. This behavior is due to the action of genotype x environment interaction (GE) analysis which constitutes a major problem for the breeding programs. The objective of this study was to evaluate the genotype x harvest cycles through its decomposition into simple and complex fraction and the agroindustrial performance RB genotypes of sugarcane (Saccharum spp.) on the south coast of Pernambuco. The experiment was conducted in harvests 2011/2012, 2012/2013 and 2013/2014, the plant Cucaú in Rio Formoso/PE municipality. We used a randomized block design with four replications, as treatments eleven clones RB 2004 series and three varieties as witnesses. They were evaluated thatched tons per hectare (TCH), tons of pol per hectare (TPH) and total recoverable sugar (ATR). The genetic-statistical analyzes were processed in the Genes software (Cruz, 2009). The means were grouped by the Scott and Knott test (1974), a 5 % error probability (p≤0.05). For the study of genotypes (G) x harvest cycles (C), and the joint analysis of variance, we proceeded to the split of GXC interaction variance component in simple and complex part, the method of Cruz and Castoldi (1991), and finally, the Pearson correlation coefficient between pairs of evaluated cycles of crops. It was found significant differences among genotypes for TCH and TPH, for GXC harvest and interaction cycles for all variables in the environmental conditions of the South Coast of Pernambuco Forest. On the decomposition of GXC interaction predominated simple fraction (FS> 60%) to TCH and TPH between pairs of harvest cycles (plant cane and first ratoon) and (first ratoon and second ratoon). A smaller percentage of the complex interaction indicates that in addition to genotypes respond in different proportion, they change performance as the environment.