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Results and discussion

Host-pathogen interaction
The infection types (ITs) of Test cultivars HD 2135, HD 2160, HD 2189, HD 2285, Vaishali and differential sets A and B, are shown in Table1. Reaction pattern of above wheat cultivars showed various infection types of resistant category to 12 pathotypes of P. graminis tritici, while AL showed susceptibility (IT4). The above reaction pattern did not permit gene postulation in test cultivars.

Inheritance of resistance
An analysis of seedlings of parents, F₁:, F₂ and families of F₃ generations with test pathotypes, is shown in Table2. F₂ ratios were further confirmed by the segregation of families in F₃.

HD 2135
The F₁ of cross HD 2135 x AL showed ;, ;1-, 4 and; to pathotypes 21(9G5), 21A-2(75G5), 40-1(62G29-1) and 117A(36G2) respectively, which were almost similar to HD 2135 except 40-1(62G29-1), to which HD 2135 showed; reaction. Out of 205 seedlings, 202 segregated for resistance and 3 susceptibility deriving the ratio 63R: 1S to pathotype 21(9G5). Seedlings of reciprocal cross also segregated in the above ratio. To 21A-2(75G5) F₂ seedlings segregated in 275 resistant and 18 susceptible showing the ratio 15R: 1S, which was also observed in reciprocal cross. F₃ families segregated in 7R: 8Seg: 1S pattern confirming the ratio obtained in F₂. F₂ seedlings were grouped as 100 resistant and 340 susceptible to 40-1(62G29-1). Also F₃ families segregated in the ratio 1R: 2Seg: 1S, thus confirming F₂ ratios both in direct and reciprocal crosses. Out of 266 seedlings, 249 segregated for resistance and 17 susceptible to 117A(36G2) deriving the ratio 15R: 1S, which was also obtained in reciprocal cross. F₃ families segregated in 7R: 8Seg: 1S and further confirmed above segregation pattern. The above analysis confirmed the presence of three dominant independent genes for resistance to 21(9G5); two dominant independent genes for resistance to 21A-2(75G5) and 117A(36G2); and one recessive gene for resistance to 40-1(62G29-1) in HD 2135.

HD 2160
In cross HD 2160 x AL, F₁ showed resistance to all pathotypes except 40-1(62G29-1). In F₂, seedlings segregated in 267 resistant and 18 susceptible to 21(9G5) deriving the ratio 15R: 1S. The above ratio was also obtained in reciprocal cross. To 21A-2(75G5), out of 358 seedlings, 270 were resistant and 88 susceptible segregating in the ratio 3R: 1S. The segregation of F₃ families in 1R: 2 Seg: 1S and seedlings of reciprocal cross in 3R: 1S pattern confirmed the above F₂ ratio. To pathotype 40-1(62G29-1) F₂ seedlings of both direct and reciprocal crosses segregated in the ratio 1R: 3S. Further segregation of F₃ families occurred in 1R: 2Seg :1S. F₂ seedlings segregated in the ratio 3R: 1S of both direct and reciprocal crosses and F₃ families in 1R: 2Seg: 1S to pathotype 117A(36G2). The above data showed the presence of two dominant genes to 21(9G5) and one dominant gene to 21A-2(75G5) and 117A(36G2); and one recessive gene to 40-1(62G29-1) in HD 2160.

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