Table 1 Genetic coefficients of millet varieties used in the study

P1

Thermal time from seedling emergence to the end of the juvenile phase (expressed in degree-days above a base temperature of 10 ℃) during which the plant is not responsive to changes in photoperiod

℃ day-1

150

160

160

P20

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

(Hours)

12.8

12

12

P2R

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

℃ day-1

120

119

100

P5

Thermal time (degree-days above a base temperature of 10 ℃) from beginning of grain filling (3–4 days after flowering) to physiological maturity

℃day-1

101

130

140

G1

Scaler for relative leaf size

–

0.7

0.6

0.35

G4

Scaler for partitioning of assimilates to the panicle (head)

–

1.95

1

1.47

PHINT

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

℃ day-1

43

43

43

GT

Tillering coefficient, equivalent to G1, but on tillers

–

1.2

1.2

1.2

G5

Potential grain size, mg

–

11

11

11