Data analysis
All the experiments were replicated three times. Data were subjected to an analysis of variance with a completely randomized factorial design. Statistical analysis was performed using SAS (2008) General Linear Model procedure performed with SAS Software Release 9.3 (SAS Institute). T-tests were used for pairwise comparisons. Least significant difference of means tests was done for multiple comparisons, and all tests were performed with a level of significance 0.05.