GENETICS OF RESISTANCE TO THE FUNGUS HELMINTHOSPORIUM-SATIVUM IN WHEAT - USE OF CULTURE FILTRATES IN TISSUE-CULTURE

Six wheat genotypes and their F-1 and F-2 generations were exposed to the action of Helminthosporium sativum culture filtrates to examine th e genetics of hexaploid wheat resistance. The objective was to improve the efficiency of breeding programs by identifying the action and num ber of genes involved in the resistance. The varied response of the te sted genotypes to the culture filtrates allowed division of the genoty pes into four groups: resistant, moderately resistant, moderately susc eptible and susceptible. This variability was detected in the progeny, suggesting that the parents have distinct genetic constitutions. Addi tive gene action predominated and genetic gain was shown to be possibl e through selection. The genetic control of the resistance trait seems to be complex because of the presence of gene interaction and the dif ficulty of eliminating the environmental effects. The inheritance seem s to be oligogenic.