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Materials and methods

The experimental materials were developed from a cross involving two varieties of bread wheat, Kharchia 65 and CPAN 1992. Kharchia 65 is drought resistant and tall in height, whereas CPAN 1992 is drought susceptible, medium in height and well adapted agronomically. The F₁ was backcrssed in 1991-92 to each of the parents (P_l and P₂) to produce the first backcross generations B₁ (P_l x F_l) and B₂ (P₂ x F_l). Seeds produced by self pollination of F_l, F₂, B₁ and B₂, generations were used to produce F₂, F₃, B_lsand B_2s generations, respectively. The final experiment was conducted during 1992-93 with the experimental materials comprising P_l, P₂, F₁, F₂, F₃, B₁, B₂, B_ls and B_2s generations under irrigated and rainfed conditions. The study was carried out at the experimental farm of the CCS Haryana Agricultural University, Hisar which is situated at 29ëB1'N latitude and 75^o46'E longitude and 215m above msl. In rainfed experiment only presowing irrigation was applied to ensure proper germination, whereas four irrigations were applied to irrigated experiment during growth period. The total rainfall during the growth period was 40 mm which was sufficient to maintain moisture stress conditions under field conditions in this area. The experiment was laid out in compact family block design with three replications. The row length was kept to 2 m, each row included 20 plants spaced 10 cm apart. Rows were spaced 30 cm apart. All measurements were taken on an individual plant basis. The non-segregating generations, i.e., parents and F1 were grown in single rows, B₁ and B₂ in 2 rows, B_ls and B_2s in 8 rows, and F₂ and F₃, in 10 rows. Data were collected on five plants from each row for days to heading, number of tillers, days to maturity, biological yield, grains/ear, 100-grain weight, grain yield and harvest index. The statistical analysis for generation means and components of variance was done according to Mather and Jinks (1982). The phenotypic correlations among all the variables were computed from F₂ generation by the method suggested by Sidwell et al. (1976). Heritability in narrow sense (h²ns) was estimated following Warner (1952). Expected gain from selection (GS) was calculated following Allard (1960), as G.S. = KƒÐph²ns, where K is the selection differential in standard units, ƒÐp is the phenotypic standard deviation (estimated as the square root of the within-plot variance for F₂ population), and h²ns is defined as above.


Results and discussion

Mean performance of parents

Performance of parental means under both irrigated (E₁) and rainfed (E₂) environments are given in Table 1. Considerable variation was observed in the mean values among the parents under E₁ and E₂ for all the characters. The mean values under irrigated conditions were considerably higher than that under moisture stress conditions. CPAN 1992 showed significantly higher mean values than Kharchia 65 for all the characters except tillers/plant under irrigated (E₁) conditions, whereas Kharchia 65 was significantly superior to CPAN 1992 for all the traits under moisture stress (E₂) conditions.

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