Note: P1, time period (expressed as growing degree days (GDD) in °C above a base temperature of 9 °C) from seedling emergence; P2O, critical photoperiod or the longest day length (in h) at which the development occurs at a maximum rate; P2R, extent to which phasic development leading to panicle initiation is delayed (expressed as GDD in °C) for each hour increase in the photoperiod above P2O; P5, time period in GDD (°C) from the beginning of grain-filling to physiological maturity; G1, potential spikelet number coefficient; G2, single grain weight (g) under ideal growing conditions; G3, tillering coefficient; G4, temperature tolerance coefficient.