highly significantp < 0.0001
Table 4 shows that one linear (A) and two quadratic variables (A 2 and B 2 ) were significant at p < 0.001, two linear terms (B, C) were significant at p < 0.01, and one interaction (AB) was significant at p < 0.05 while one quadratic variable was highly significant at p < 0.0001.