The experiment was conducted at five locations viz., Barisal, Jamalpur, Gazipur, Ishurdi and Rangpur during rabi 2011-12. Thirty eight CIMMYT developed white-QPM hybrids and two local checks, viz. BARI Hybrid Maize-5 (BHM 5) and BARI Hybrid Maize-9 (BHM-9) were evaluated in this trial. Seeds were sown on November to December, 2011 at 5 locations following Alpha lattice design with 3 replications. The unit plot size was 5.0 X 1.5 m. Spacing adopted was 75 cm × 20 cm between rows and hill, respectively. One healthy seedling per hill was kept after proper thinning. Fertilizers were applied @ 250, 120, 120, 40 and 5 kg ha-1 of N, P205, K20, S and Zn, respectively. Standard agronomic practices were followed (Quayyum, 1993) and plant protection measures were taken as required. Two border rows were used to minimize the border effect. Data on days to tasseling and days to silking were recorded on whole plot basis. Ten randomly selected plants were used for recording observations on plant and ear height. All the plants in two rows were considered for plot yield. The grain yield (t ha-1) data was assessed and corrected to 12% moisture. The CIMMYT hybrids are: CLWN210/CML494, CLWN224/CML494, CLWN208/CML494, CML494/CML495, CML491/CML503, CLWN221/CML494, CLWN216/CML494, CLQRCWQ124/CML491, CLWN211/CML494, CLWQ222/CML503, CL04368/ CLSPLW04, CLWN205/CML494, CLWN209/CML494, CLWQ238/CML491, CLWN228/CML495, CLWN212/CML494, CLWN219/CML494, CLWN217/ CML494, CLWQ223/CML503, CLWN227/CML495, CLRCW104/CML494, CLWN218/CML494, CLRCW105/CML494, CLWN215/CML494, CLQRCWQ123/ CML491, CLWN204/CML494, CLWN222/CML494, CLWN207/CML494, CLWN206/CML494, (CLQ-6203xCL-04321)-B-7-1-2-4-B/CL-FAWW11)-B-6-1-2- B-B-B-B/CML491, CLWN220/CML494, CLWQ221/CML503, CLWN213/ CML494, CLWN214/CML494, CLRCW107/CML494, CLWN223/CML494, CLWN201/CML495, CLRCW109/CML494. All the materials were marked as E and considered as individual entry.
Statistical Analysis
The analysis of variance (ANOVA) was used and the GE interaction was estimated by the AMMI model (Duarte and Vencovsky, 1999). Thus, the mean response of the genotype i in environment j (Yij) is modeled by: Yij = μ + gi +aj + Σλkγikαjk + ρij +eij ; where μ is a common constant to the responses (normally the general mean); gi is the fixed effect of genotype i (i = 1, 2, ..., g); aj is the fixed effects of environment j (j = 1, 2, ..., a); Σλkγikαjk is the fixed significant effect or pattern of the specific interaction of the genotype i with environment j (gaij), where, λk is the k-th singular value (scalar), γik and αjk are the correspondent elements, associated to λk, of the singular vectors (rows vector and column vector) of the matrix of interaction estimated by ANOVA. For the same matrix, ρij is the non-significant effect or noise of (ga)ij, which is an additional residue, and eij is the pooled experimental error, assumed independent and eij ~ N(0, σ2). In this procedure, the contribution of each genotype and each environment to the GE interaction is assessed by the biplot graph display in which yield means are plotted against the scores of the first principal component of the interaction (IPCA1). The stability parameters, regression coefficient (bi) and deviation from regression (S2di) were estimated according to Eberhart and Russell (1966). Significance of differences among bi value and unity was tested by t-test, between S2di and zero by F-test. All the data were subjected to analysis using statistical analysis package software Cropstat7.2 version (AMMI, SSA and BANOVA models).