Table 3 Sweet sorghum cultivar coefficients

P1

Thermal time from seedling emergence to the end of the juvenile phase (expressed in degree days above TBASE during which the plant is not responsive to changes in photoperiod)

P2O

Critical photoperiod or the longest day length (in hours) at which development occurs at a maximum rate. At values higher than P2O, the rate of development is reduced

P2R

Extent to which phasic development leading to panicle initiation (expressed in degree days) is delayed for each hour increase in photoperiod above P2O

P5

Thermal time from beginning of grain filling to physiological maturity (degree days above TBASE)

G1

Scaler for relative leaf size

G2

Scaler for partitioning of assimilates to the panicle (head)

PHINT

Phylochron interval; the interval in thermal time between successive leaf tip appearances (degree days)

P3

Thermal time from the end of flag leaf expansion to anthesis (degree days above TBASE)

P4

Thermal time from anthesis to beginning of grain filling (degree days above TBASE)

P2

Thermal time from the end of the juvenile stage to tassel initiation under short days (degree days above TBASE)

PANTH

Thermal time from the end of tassel initiation to anthesis (degree days above TBASE)