Genetic analysis of resistance to Karnal bunt (Tilletia indica (Mitra)) in bread wheat

Abstract

An analyis of an Fl-based incomplete diallel was conducted involving 11 parents with different levels of resistance to Karnal bunt (Tilletia indica (Mitra)). It demonstrated that general combining ability (GCA) and thus additive or additive × additive gene effects were very important in the inheritance of resistance, accounting for 86.9% of the variation. Further analysis concentrated on F3 lines derived from individual random F2 plants from crosses with resistant varieties having the highest negative GCA effects. It was shown that the varieties Weaver and W499 have single dominant genes of resistance, which are different from each other, and which differ from a single allelic gene in varieties K342 and Cruz Alta. The majority of the crosses did not demonstrate 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.

Mapping of a resistance gene effective against Karnal bunt pathogen of wheat

“…The distribution of KB disease severity on the RILs was skewed toward that of the resistant-parent in three experiments, suggesting the segregation of multiple genes with dominant or complementary gene action in wheat line HD29. This is consistent with the results of previous studies (Morgunov et al 1994;Fuentes-Dávila et al 1995). The heritability of 0.69 on entry mean basis for KB resistance in this population is consistent with other findings showing that resistance to KB in wheat is highly heritable and under relatively simple genetic control Nelson et al 1998).…”

“…Previous genetic studies on KB resistance in wheat indicated that one to six major genes condition resistance in various wheat germplasms (Morgunov et al 1994;Fuentes-Dávila et al 1995;Singh et al 1995aSingh et al , b, 1999Villareal et al 1995). Six wheat chromosomes (1D, 2A, 3B, 3D, 5D and 7A) were identified as influencing reaction to the pathogen (Gill et al1993;Singh et al 1994).…”

Genetic analysis of karnal bunt resistance in 14 Mexican bread‐wheat genotypes

“…Pooled y^ confirmed these results. Morgunov et al (1994) also reported the monogenic control of resistance in four resistant genotypes.…”

“…The best way to control this disease is through the use of resistant cultivars. Breeding for Karnal bunt resistance is a major activity at CIMMYT (International Maize and Wheat Improvement Center) and in a few national programmes in India (Morgunov et al 1994). To support these programmes, knowledge of the genetics of resistance is important.…”

“…The earlier genetic studies by Chand et al (1989) and Gill et al (1990) reported partial dominance of resistance and predominance of additive and additive x additive gene actions. In a recent study Morgunov et al (1994) reported monogenic control of resistance in four resistant lines.…”