Resistance of melon genotypes to Meloidogyne incognita and M. javanica: an approach based on genetic parameters estimated via REML/BLUP

Abstract Melon is one of the main vegetable crops grown in Brazil and is severely affected by root-knot nematodes of the genus Meloidogyne . The identification of resistance sources is therefore essential. Estimates of genetic parameters in breeding programs provide insight into the effects underlying the traits under evaluation. The objective of this study was to identify melon accessions resistant to Meloidogyne incognita and M. javanica and to estimate genetic parameters using the REML/BLUP procedure. Four independent trials were conducted, two for M. incognita and two for M. javanica . In the initial screening trials, 41 melon accessions were evaluated. Ten accessions (nine classified as resistant to both species and one resistant only to M. incognita ) were re-evaluated to confirm resistance. In the screening trials, 71 and 26.8% of the genotypes were classified as resistant to M. incognita and M. javanica , respectively. In the confirmation trials, five genotypes retained resistance to M. incognita , whereas only two maintained resistance to M. javanica . The Scott–Knott test identified distinct groups in all trials for both nematode species. Broad-sense heritability was low to moderate, and selection accuracy was moderate. Accession AC-18 exhibited resistance to both nematode species and is a promising genotype for melon breeding programs. Five accessions were resistant to M. incognita , whereas only two were resistant to M. javanica .