fitReg: a function to model the phyllocron using a linear regression
In sanchezi/phisStatR: Phenoarch Greenhouse Data Analysis

Description Usage Arguments Details Value Examples

this function models each plant of a dataset using a regression to extract the slope (i.e. phyllocron: the rate of leaf appearance)

1	fitReg(datain, trait, xtime, myylim, reference, myxlab)

`datain`	input dataframe (wide format, as many columns as variables)
`trait`	variable to modelize (example visible_leaf, F_visible)
`xtime`	character, name of thermal time column in the input dataset (example thermaltime)
`myylim`	maximum value of y-axis for graphic
`reference`	character, a column name indicating an unique identifiant of plant (example: Ref == concatenation of experimentAlias-Line-Position-scenario)
`myxlab`	character, a x label for the output graphics

the input dataset must contain a thermalTime column (numeric data) and a Ref column (unique id)

a list of two elements and the graphics of the regression

1: a dataframe of the predictions of the slope for each plant (phyllocron)

2: a list of fitted models for each plant for diagnostics purposes

# Take a while...
 resu<-fitReg(datain=plant2,trait="F_visible",xtime="thermalTime",
              myylim=22,reference="Ref",
              myxlab="Thermal Time degD")
 str(resu)