GENETIC-ANALYSIS OF RESISTANCE TO KARNAL BUNT (TILLETIA-INDICA (MITRA)) IN BREAD WHEAT

An analyis of an F1-based incomplete diallel was conducted involving 1 1 parents with different levels of resistance to Karnal bunt (Tilletia indica (Mitra)). It demonstrated that general combining ability (GCA) and thus additive or additive x additive gene effects were very impor tant in the inheritance of resistance, accounting for 86.9% of the var iation. Further analysis concentrated on F3 lines derived from individ ual random F2 plants from crosses with resistant varieties having the highest negative GCA effects. It was shown that the varieties Weaver a nd W499 have single dominant genes of resistance, which are different from each other, and which differ from a single allelic gene in variet ies K342 and Cruz Alta. The majority of the crosses did not demonstrat e a relationship between Karnal bunt infection and the number of days to heading. Resistant F3 lines varied in the number of days to heading from 80 to 100.