GENETICS OF SLOW LEAF RUSTING IN WHEAT

Abstract

Two sets of materials were produced involving 22 wheat cultivars to study the genetics of slow leaf rusting. In Set I, seven generations (two parents, Ft, F2, F3, BCl and BC2) of three crosses (Kalyan Sona X Pavon, Kalyan Sona x WH 147, and K 68 X Veery'S') were raised and the data analysed to estimate various genetic parameters and test the adequacy of models. In Set II, 60 triple test-cross families produced by crossing 20 wheat cultivars with three testers (Kalyan Sona, Pavon and their Fd were evaluated to detect epistasis and estimate D and H components of genetic variation. The 6-parameter model explained best the inheritance of slow leaf rusting in the material of Set I. Partial dominance was indicated by all the three crosses and the genes causing less disease were dominant over their alleles causing more disease. Duplicate epistasis was present in all the three crosses. The results of the two sets were similar except that a case of complete dominance tending towards overdominance was indicated in Set II.