Seventy-two field trials were conducted by applying four defoliation
treatments (non defoliated control, 33%, 66%, and 100%) at different
growth stages (stage) ranging from pre-flowering (1) to physiological
maturity (5) in four different locations of Navarra, Spain: Carcastillo (1),
Melida (2), Murillo (3), and Unciti (4). There are two response variables:
yield in kg/ha of the sunflower and numseed, the number of
seeds per sunflower head. Data are stored in the data frame
sunflower. Data used in Case Study: Sunflower defoliation from
Chapter 11.
A data frame with 72 observations on the following 5 variables:
a factor with levels A, B,
C, and D for locations Carcastillo, Melida, Murillo, and
Unciti respectively
a factor with levels stage1, stage2, stage3, stage4, and
stage5
a factor with levels control,
treat1, treat2, and treat3
sunflower yield in kg/ha
number of seeds per sunflower head
Muro, J., et. al. (2001) “Defoliation Effects on Sunflower Yield Reduction.” Agronomy Journal, 93: 634-637.
Ugarte, M. D., Militino, A. F., and Arnholt, A. T. (2008) Probability and Statistics with R. Chapman & Hall/CRC.
summary(aov(yield ~ stage + defoli + stage:defoli, data = sunflower))#> Df Sum Sq Mean Sq F value Pr(>F) #> stage 4 5186036 1296509 1.267 0.29495 #> defoli 3 13720078 4573359 4.468 0.00726 ** #> stage:defoli 12 16236084 1353007 1.322 0.23500 #> Residuals 52 53224683 1023552 #> --- #> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1