Análises multivariadas aplicadas na seleção de famílias nas fases iniciais do melhoramento genético de cana-de-açúcar

Abstract

The aim of this study was to evaluate sib families with potential sugarcane production and earliness in maturity, in order to select individuals for use in breeding and commercial. The experimental design was randomized blocks with four blocks and ten families of sugar cane. The experiment was carried out in the agricultural area in sugar mill São José - Igarassu/PE, during the agricultural year 2009/2010. Were evaluated the characters mean number of culms (NMC), mean diameter culms (DMC), mean height of culms (AMC), mean weight of culms (PMC), tons of cane per hectare (TCH), tons per hectare of pol (TPH), brix tons per hectare (TBH), pol in cane (PC), brix in sugar cane (BC), % cane fiber (FIB), total recoverable sugar (ATR) and pure cane (PUR). The analysis of variance was performed for all the characters and the means were grouped by Scott and Knott test (1974), 5% of probability (p<0.05). The multivariate analysis was used to quantify the genetic divergence. The Mahalanobis distance was used as dissimilarity measure. Were applied the hierarchical method of the average linkages (UPGMA) and the optimization method of Tocher. Were estimated the phenotypic path analysis. Families FA-2, FA-3, FA-5, FA-8 and FA-9, can be selected for production of sugarcane and sugar. The results based on brix families indicated FA-4 FA-5 FA-6 FA-10 and with a tendency to early maturity. The use of pairs of different families can be recommended for use in improving opportunities to provide new combinations with success in the selection. Indirectly, the selection of families for the production of cane and sugar can be done by the average number of culms.