Intermediate resistance to nematode Meloidogyne paranaensis in Híbrido de Timor coffee genotypes

Abstract

The aim of this study was to prove that Híbrido de Timor (HdT) accessions are resistance sources to Meloidogyne paranaensis. Two experiments were carried out in a greenhouse at IDR-Paraná (Londrina, Paraná State, Brazil). Open pollinated fruits were harvested from 10 accessions (HdT UFV 380-05, HdT UFV 408-10, HdT UFV 408-11, HdT UFV 408-28, HdT UFV 428-04, HdT UFV 439-14, HdT UFV 443-08, HdT UFV 445-70, HdT UFV 446-138, HdT UFV 448-75) from the EPAMIG/ UFV germplasm bank. Seeds of these accessions were sown to obtain seedlings to test the resistance to M. paranaensis. For each experiment, a completely randomized design was used with 11 treatments, eight replications and one plant per plot. Cultivar Mundo Novo IAC 376-4 was the susceptible check. Seedlings with three to four pairs of leaves were transplanted into plastic cups with a capacity of 700 mL and 1200 eggs. The J2 of M. paranaensis (IP) were inoculated after one month. The assessments were performed 134 days after inoculation, when the data of the number of eggs and J2 per gram of roots and the final population of nematodes (FP) were obtained. The reproduction factor (RF) was calculated using the formula: RF = IP / FP. To classify the resistance levels of the genotypes, the reproduction factor reduction (RFR) was used. It classified the levels from highly resistant to highly susceptible. Different levels of intermediate resistance between the accesses were observed, highlighting HdT UFV 408-28 that presented moderate resistance to M. paranaensis. HdT UFV 408-28 showed a high percentage of plants with intermediate resistance, which can be used in breeding programs aimed at resistance to M. paranaensis