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Genetics of resistance to the fungus Helminthosporium sativum in wheat: use of culture filtrates in tissue culture
Rosa Lía Barbieri; Fernando Irajá Félix de Carvalho; Ana Lúcia Cunha Dornelles; Rosa Maria de Luján Oviedo de Cristaldo; Cristine Luise Handel
Departamento de Plantas de Lavoura, Faculdade de Agronomia, Universidade Federal do Rio Grande do Sul, Caixa Postal 776, 95501-970 Porto Alegre, RS, Brasil. Send correspondence to R.L.B.
ABSTRACT
Six wheat genotypes and their F1 and F2 generations were exposed to the action of Helminthosporium sativum culture filtrates to examine the genetics of hexaploid wheat resistance. The objective was to improve the efficiency of breeding programs by identifying the action and number of genes involved in the resistance. The varied response of the tested genotypes to the culture filtrates allowed division of the genotypes into four groups: resistant, moderately resistant, moderately susceptible and susceptible. This variability was detected in the progeny, suggesting that the parents have distinct genetic constitutions. Additive gene action predominated and genetic gain was shown to be possible through selection. The genetic control of the resistance trait seems to be complex because of the presence of gene interaction and the difficulty of eliminating the environmental effects. The inheritance seems to be oligogenic.
Keywords: resistance; fungus; wheat.
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