Progressos genéticos, desempenho agronômico e reação de progênies de cafeeiros arábica a Meloidogyne exigua e M.paranaensis

Abstract

In this study aimed to provide information about agronomic characteristics and reaction to leaf rust of progenies of coffee tree F3:4 , and also verify genetic correlations among characters, estimate parameters and genetic progress and characterize the progenies F 4:5 reaction to parasitism by Meloidogyne paranaensis and Meloidogyne exigua. Three experiments were conducted. The field experiment was installed in December 2000, at Ouro Verde Farm, located in Campos Altos, Minas Gerais State, Brazil. Ten progenies of F3:4 were evaluated from Timor Hybrid selections x Catuaí group cultivars crossing, previously selected as resistant to M. exigua and the Catuaí Vermelho IAC 99 cultivar as the control. The randomized block design was used, with three replicates, totaling 33 plots consisting of eight plants each, spaced 4.0 x 0.8 m. Among the 2011/2012 to 2014/2015 crop seasons, it was evaluated productivity (conditioned coffee bags ha -1 ), incidence and severity of leaf rust, vegetative vigor, percentage of fruits at the “cherry” stage, percentage of floating fruits, crown diameter, percentage of grains sieve 17 above and sensory analysis of drink. Most of progenies stands out in productivity; all progenies show promising performance for resistance to coffee rust and potential for the production of specialty coffees; the progenie H493-1-2-2 stands out in all evaluated characteristics. Within ten progenies superior in field, 86 plants were selected, which these plants were self-fertilized to obtain the F4:5 generation. Two experiments were conducted in greenhouse, with inoculation of M. exigua and the other with M. paranaensis, in a randomized block design, with eight replicates and plots consisting of a plant. Eighty-six progenies and control cultivars Mundo Novo IAC 379/19, Catuaí IAC 99, Paraíso MG H 419-1 and IPR 100 were evaluated using the dry matter of shoots, fresh weight of extracted root, increase in height, increase in diameter, gall index, gall index and thickening, percentage of root system with galls, number of eggs and juveniles J2 per gram of root, reproduction factor and reduction on reproduction factor. Most progenies is resistant to M. exigua; the evaluated variables are genetically correlated; note scale based on presence of galls and/or thickening of the roots, represents well the nematodes reproduction of M. exigua and M. paranaensis; five progenies showed promising performance for resistance to M. paranaensis; there is possibility of selective gains for the decrease nematode population in the root system of progenies.