Spike phenological development of the four genotypic combinations with and without GA3 treatment in the three experiments.

Data are the duration days (d) with calculated thermal time (°C d) in parenthesis; SW: sowing date, DR: double ridge formation date, AN: anthesis date. All data are means of each genotype. Statistical analysis was carried out using the thermal time. Different letters within columns indicate statistically significant differences (P0.05).