in which Dsi refers to the DPDs of tomato in the ith stage; ki
refers to the basic development coefficient of tomato in the
ith stage, which is determined by the genetic characteristics of
this variety. In accordance with Equation (1), we know that
the variety with a small ki has a fast growth and belongs to
an early maturing variety; on the other hand, the variety with
a big ki has a slow growth and belongs to a late maturing
variety.