3. Results
3.1. Development
While genotypes differed in cycle length, no significant density
effects were observed on development in neither of the 2 years.
Cultivar Faro had the longest cycle, followed by CO-407 and RU-5.
Cultivar NL-6 had the shortest cycle and the shortest thermal time
to anthesis (Table 1). The most variable phase (in terms of thermal
time) among genotypes was largely the vegetative one, which
extended about one third of total cycle length (range: 27–32% in
2003 and 34–39% in 2004), while the flowering phase was roughly
similar. Maximum leaf number in the main stem differed among
genotypes and showed the same trend as cycle length. Phyllochron
values were between 15.5 and 21.7 ◦Cd (Tb = 3 ◦C) across genotypes,
densities and years. In 2004 both phyllochron and maximum leaf
number were lower than in 2003 resulting in a shorter reproductive
phase (Table 1).
3.2. Leaf area index and crop development
Leaf area index values were higher in 2003 than in 2004 (Fig. 2).
A high rainfall period stopped sharply the increase of leaf area in the
second year. In 2003 average maximum LAIs across genotypes were
higher in d2 than in d1 (2.20 vs. 1.77; p < 0.02). Maximum LAIs differed
among genotypes (p < 0.01). Faro presented the highest value
(2.60, average over densities), CO-407 the intermediate (2.11); NL-6
and RU-5 the lowest (1.63 and 1.61, respectively). In 2004 maximum
LAIs only reached 0.99 and 1.35 (average across genotypes) for d2
and d3 (p > 0.12). Only Faro (a late genotype) had significant different
values (p < 0.05) between densities (0.75 vs. 2.09 for d2 and d3).
Maximum LAIs did not differ among genotypes (range 0.93–1.42)
for the second year