Genetic parameters of resistance to meloidogyne incognita in melon/Parametros geneticos da resistencia a meloidogyne incognita em meloeiro

In order to assess the genetic control of resistance in the melon 'Gaucho Redondo ' to the root-knot nematode Meloidogyne incognita, an experiment was conducted in a randomized complete block design with three blocks and six treatments using the parental lines 'Gaucho Redondo' ([P.sub.1] resistant) and JAB 20 ([P.sub.2] susceptible), as well as [F.sub.1], [F.sub.2], and backcross generations ([RC.sub.1][p.sub.1] and [RC.sub.1][p.sub.2]). Seventy days after inoculation, individual plants were evaluated for resistance using the nematode reproduction factor (RF). The hypothesis of monogenic inheritance was rejected by the chi-square test ([chi square]), and results indicated that resistance is controlled by more than one gene locus, as confirmed by the quantitative analysis that revealed the presence of six genes. Key words: Cucumis melo, genetic inheritance, plant breeding, reproduction factor. Com o objetivo de avaliar o controle genetico da resistencia do melao 'Gaucho Redondo' ao nematoide de galha Meloidogyne incognita, foi conduzido um experimento em blocos casualizados com tres blocos e seis tratamentos, os quais envolveram as linhas parentais 'Gaucho Redondo' (P , resistente) e JAB 20 ([P.sub.2], suscetivel), assim como as geracoes F, [F.sub.2], e retrocruzamentos (RCp, e RC p). Avaliaram-se plantas individuais apos 70 dias da inoculacao com o patogeno, por meio do fator de reproducao do nematoide (FR). A hipotese de heranca monogenica foi rejeitada pelo teste do qui-quadrado ([chi square]), indicando que a resistencia esta sob controle de mais de um loci genico, sendo confirmado pela analise quantitativa, que evidenciou a presenca de seis genes. Palavras-chave: Cucumis melo, heranca genetica, melhoramento de plantas, fator de reproducao. Palavras-chave: Cucumis melo, heranca genetica, melhoramento de plantas, fator de reproducao.