Avaliação de progênies da fase inicial T1, para indicação de genitores elites de cana-de-açúcar para Pernambuco

Abstract

In Brazil, there are several programs of genetic improvement for sugarcane (Saccharum spp.), which most of them use the phenotypical or massal selection in T1 phase. These programs show relative success, once quantitative genetical studies indicate that the massal selection in T1 phase shows low efficiency. So, many researches were done in order is find new methods to increase the efficiency of the selection in its various phases. In this context distinguishes the selection by families in progenies in T1 phase. Therefore, the objective of this work was to evaluate the agroindustrial performance and to analyze the magnitude of some genetical parameters in families of progenies in T1 phase of sugarcane within the sugarcane plantation microregions from North Forest and North Coast of the state of Pernambuco. Experimental works in cane-plant were developed during the agricultural year of 2006/2007 at the Central Olho d’Água mill, located at the North Forest of Pernambuco, municipal district of Camutanga (07°24’ S, 35°28’W) and São José mill, located at the North Coast of Pernambuco, municipal district of Igarassu (08°45’S, 35°00’W). The adopted experimental delineation was the randomized blocks, with 5 of them, using 37 and 24 treatments for the experiments conducted at North Forest and North Coast, respectively. The experimental unit was represented by three furrow of 6 m each, spaced by 1,30 m with tem seedlings per furrow, spaced by 06 m within the furrow, totalizing 30 seedlings per parcel, making a total area of parcel of 23,4 m2. The harvest was made in the 10th month after the transplantation where were evaluated the variables: sugarcane tons per hectare (STH), pol tons per hectare (PTH), fiber (FB), corrected pol % (CPP), purity (PTY), brix (BX), total retrievable sugar (TRS). In the experiment conducted at North Forest, the over topping progenies of the crossings were: RB 865230 X RB 855035, TUC 77-42 X RB 83102, Co 434 X RB 946915, RB 972551 X CP 69-1062, RB 855063 X IAC 87-3396, RB 855035 X RB 865230, RB 915141 X RB 855322, RB 855035 X RB 72454, RB 83102 X TUC 77-42, IAC 87-3396 X RB 855063, SP 71-6949 X RB 83102, RB 72454 X TUC 71-7 e SP 71-6949 X TUC 71-7 for all studied variables. There was genetical variability among the progenies for all variables, but the h2 m estimations were expressive for the variablies PTH, STH, CPP and BX indicating the possibility of the success in the selection of these variables. While the experiment conducted at North Coast, the progenies of the crossings over topped were RB 855035 X RB 72454; H 64-1881 X F-150; RB 865230 X RB 855035; TUC 71-7 X RB 72454; RB 855035 X RB 865230 e RB 72454 X TUC 71-7 for the variables PTH, STH, CPP, BX e TRS. The result of these genetical analyses indicated the existence of genetical variability among the progenies of the crossings for all evaluated variables, but the h2 m estimations were elevates for the variables PTH, STH, CPP, BX and TRS, indicating the possibility of success in the selection of these variables.