Indução de mutação por meio de irradiação gama em cultivares de Bananeira

Abstract

One of the factors that lead to great losses in banana production is toppling due to tall height of the pseudostem in some commercial cultivars. An alternative to overcome this limitation is height reduction by inducing mutation using gamma radiation. This work was developed at Embrapa Cassava and Tropical Fruits aiming to evaluate the genetic variability of irradiated Prata type bananas (´Pacovan´ and ´Preciosa´) and test the sensitivity to radiation in the Terra Maranhão cultivar in order to identify the best dose of gamma rays for mutation in this cultivar. The work was subdivided into three chapters: in the first one the agronomic characterization of Pacovan and Preciosa mutants aiming the selection of shorter plants was carried out; in the second chapter the agronomic characterization was compared with ISSR markers in order to estimate the genetic diversity between the mutants; in the third chapter the best radiation dose for inducing mutation in the Terra Maranhão cultivar was assayed. The results indicated that there is genetic variability for most agronomic characteristics between the irradiated ´Pacovan´ as well as in the ´Preciosa´ plants which allowed for the selection of four shorter irradiated plants from each cultivar and good agronomic characteristics. Through molecular analysis it was observed that the ISSR markers were efficient in detecting genetic variability between the irradiated plants of the Pacovan and Preciosa cultivars. The sensitivity test carried out with the Terra Maranhão cultivar indicated that the doses of 20 and 30 Gy are the best ones recommended for this genotype.