highly significantP ≤ 0.0001
The variance (ANOVA) analysis of the significance of the quadratic polynomial models 4 of the content of TTSs showed that the coefficients of linear ( X 1 , X 2 , X 3 and X 4 ) and quadratic coefficients ( X 3 2 ) were highly significant ( P ≤ 0.0001) with regard to the content of TTSs.