Desempenho agronômico de progênies de Coffea arabica L. resistentes aos nematoides das galhas

Abstract

Nematodes of the genus Meloidogyne spp. they are widespread in several coffee producing regions in Brazil, causing a significant reduction in crop productivity. In infested areas, the use of cultivars with genetic resistance is the main strategy to maintain production. Therefore, this study aimed to evaluate the performance of Coffea arabica progenies, originating from the Amphillo germplasm, aiming to obtain cultivars that show resistance to Meloidogyne paranaensis and Meloidogyne exigua nematodes with good agronomic characteristics. Two experiments were installed in different locations. The first experiment was planted at Fazenda São Judas Tadeu in an area infested by M. paranaensis, located in the municipality of Piumhi-MG. It was composed of nine progenies in F6:7 generation and the cultivar Catuaí Amarelo IAC 62 as a susceptible control and the cultivar IPR 100 as a resistant control. The design used was in randomized blocks with five replications and 15 plants in the plot. The nematode population in the experimental plots was evaluated using Biotest in tomato plants and the population in the roots of the progenies and cultivars in 2019 and 2020. At 12 and 24 months, the increase in plant height, stem diameter and number of branches primary plagiotropic agents. In May 2020 the vegetative vigor, crown diameter, length of the internode of the orthotropic stem, productivity in bags of coffee benefited by ha-1 were evaluated; percentage of green fruits, cherry, dried, chochos, sieve 17 and above, mocha grains and lace. Most of the progenies were resistant to M. paranaensis and the MG 0185-2-R2-11-7-I (44A) progeny showed good vegetative performance combined with high productive potential and early maturation cycle. The second experiment conducted at Fazenda Santa Cecília in an area infested by M. exigua, in the municipality of Carmo do Paranaíba-MG, was composed of eight progenies in F6:7 generation, the cultivar Catuaí Vermelho IAC 99 and the cultivar IPR 100. The design was in randomized blocks with four replications and 10 plants in the plot. The nematode population (eggs + J2) in the roots of the progenies and cultivars in 2019 and 2020 were evaluated. At 12 and 24 months, the plant height, stem diameter and number of primary plagiotropic branches were evaluated. In May 2020 the vegetative vigor, crown diameter, length of the internode of the orthotropic stem, productivity in bags of coffee benefited by ha-1 were evaluated; percentage of unripe fruits, cherry, dried, chochos, sieve 17 and above, mocha grains, income and drink. The progenies were not resistant to M. exigua by the methodology used. However, they had on average half the number of eggs and juveniles in their roots when compared to the susceptible cultivar used as a control. The progenies MG 0179-1-R1-10-2-II (20A) and MG 0179-1-R1-10-7-II (20B) stood out in relation to the others in terms of productivity and early maturation cycle.