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Inter-relationship among parents
F₂ seedlings of crosses of HD 2135 with four other parents, HD 2160, HD 2189, HD 2285 and Vaishali, when analysed with 21(9G5), 21A-2(75G5) and 117A(36G2) did not segregate for susceptibility (Table 3). All the seedlings showed; or 0; reaction and indicated that a common factor(s) provided resistance to above pathotypes. However, segregation in the ratio 61R: 3S in cross HD 2135 x Vaishali to 40-1(62G29-1) showed the involvement of two dominant and one recessive factors for resistance.
With pathotypes 21(9G5), 21A-2(75G5) and 117A(36G2), F₂ seedlings of crosses HD 2160 with HD 2189, HD 2285 and Vaishali showed only resistant seedlings due to common gene(s) for resistance in them. F₂ seedlings of crosses HD 2160 x HD 2189 and HD 2160 x HD 2285 also showed resistance to 40-1(62G29-1), but segregated in 61R: 1S ratio in HD 2160 x Vaishali. The above segregation explains the presence of two dominant and one recessive gene providing resistance to above pathotype.
HD 2189, when crossed with HD 2285 and Vaishali, F₂ population showed resistance to all pathotypes. Also, F₂ seedlings of cross HD 2285 x Vaishali did not segregate for susceptibility and showed a common factor providing resistance to 21(9G5), 21A-2(75G5), 117A(36G2) and 40-1(62G29-1).

Test of allelism with isogenic lines
Sharma (1990) postulated genes Sr2, Sr11 and Sr30 in HD 2189; and genes Sr2, Sr5, Sr11, Sr17 and Sr30 in HD 2285 with Australian pathotypes of stem rust. Therefore, HD 2189 and HD 2285 were crossed with two isogenic wheat lines Sr11 and Sr30. The F2 seedling analysis of above crosses did not show segregation for susceptibility to pathotypes 21(9G5) and 117A(36G2) and confirmed the presence of Sr11 and Sr30 in HD 2189 and HD 2285. Crosses of these parents with Sr2 and Sr17 were not made since Sr2 expresses in adult plants and Sr17 does not provide resistance to Indian pathotypes of stem rust. Also crosses of parents with Sr5 could not be made due to non synchronous flowering.
An adult plant resistance gene Sr2 was identified in HD 2135, HD 2189, HD 2285 and Vaishali based on mottling effect in the seedlings (McIntosh 1992). Sr2 was initially derived from 'Yaroslav' a tetraploid wheat by McFadden (1930). Inheritance of resistance in CIMMYT semidwarfs is associated with Sr2 gene complex derived from variety 'Newthatch'(Rajaram et al. 1988). Through CIMMYT wheats, Sr2 has gone to many developing countries including India. Sr2 was also identified in many other Indian wheats (Bahadur et al.1993).
Sharma (1990) identified Sr30 in 29 wheat varieties with Australian pathotypes of stem rust. Gene Sr11 was identified in cvs. HD 2189 and HD 2285 in the present study. Gandhi (1967) reported an additional gene along with Sr11 in E 581. Sr11 also conferred resistance in two sister selections of Kalyansona- Siete cerros and Indus 66 (Mclntosh 1988) and in 15 other wheats of Indian origin (Bahadur et al. 1993). The other genes identified in HD 2135, HD 2160 and Vaishali require further confirmation through test of allelism.

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