2.6. Yield response factor
The relationship between relative evapotranspiration reduction
and relative yield reduction was determined using the method
given by Doorenbos and Kassam (1979), following Eq. (3):
1 − Ya
Ym
= ky
1 − ETa
ETm
(3)
where Ya is the actual seed yield (kg ha−1), Ym is the maximum seed
yield (kg ha−1), ky is the yield response factor, ETa is the actual evapotranspiration
(mm), and ETm is the maximum evapotranspiration
(mm).
2.7. Statistical evaluation
Analysis of variance (ANOVA) was conducted to evaluate the
effects of treatments on yield and quality parameters. Duncan’s
multiple range tests were used to compare and rank the treatment
means. Differences were declared significant at P < 0.05 or 0.01.
The variance analysis was conducted using SPSS 13.0 computer
program.