Thermal time to first anthesis and maximum leaf number in
the main stem were linearly correlated (r2 = 0.87 n = 16; p < 0.0001).
First anthesis of early genotypes (NL-6 and RU-5) occurred a little
thermal time (about 60 ◦Cd) before the last leaf appeared on the
main stem. In late genotypes (CO-407 and Faro), the occurrence of
maximum leaf number coincided with first anthesis (Fig. 3).
Description of LAI was restricted to the first year since in 2004
waterlogging affected LAI evolution. In 2003 leaf area increase
continued until shortly after first anthesis in the main stem and
up to beginning of grain filling in branches. Occurrence of maximum
leaf area both in main stem and in branches correlated
with development stages. Days to maximum leaf area on the main
stem were highly correlated with days to first anthesis (r2 = 0.99,
n = 8, p < 0.00001) and days to maximum leaf area in branches
were highly correlated with days to end of anthesis (r2 = 0.86; n = 8,
p < 0.001). Maximum leaf area in the main stem occurred, on average,
18 days after first flower opened, while maximum leaf area
in branches was observed 6 days after the completion of anthesis
(Fig. 4).
Logistic models adequately described total plant leaf area evolution
(r2s > 0.96; p < 0.0005) (Fig. 5). No losses due to senescence
were modeled; senescent leaf biomass was less than 5% of total
(green + dead) leaf biomass during the period analyzed. Parameters
“b” of the model (thermal time needed to reach 50% of
TPLAmax) were highly correlated with maximum main stem leaf