Uso da giberelina GA3 na sele??o do porte de bananeira das cultivares prata e prata-an?

摘要

This work aimed to develop a methodology for the selection of plants with different heights using gibberellin. The study was carried out under greenhouse conditions at Embrapa Cassava and Tropical Fruits, located at Cruz das Almas - BA (12o 48' 38" South latitude and 39o 06' 26" longitude West), during the period of September 2002 through January 2003. For the comparison of different heights of Prata Dwarf and Prata Gigante cultivars, different concentrations of gibberellic acid (0; 3.0; 14.0; 29.0; 59.0; and 145.0 μmol L-1) were used in order to evaluate plant height and height of first leaf at 30 and 60 days after planting. Also the stem diameter, fresh and dry matter of the root and above ground plant parts and height of the second leaves, were evaluated at 60 days after planting. The concentration that demonstrated the greatest effect in the characteristics evaluated was 84 μmol L-1; whereas for plant height at 60 days was 90.26 μmol L-1. In general, a maximum peak around 90 μmol L-1 of gibberellin dosage was observed for the variables in study. The concentration of 94.13 μmol L-1 of gibberellic acid (GA3 ) was the most efficient in the early identification of height of the Prata Dwarf and Prata Gigante. The adequate time to separate the genotypes with different heights is at 60 days after planting and the variable that must be observed at the time of the selection is the height of the second leaf.