Plant growth and yield components
Table 1 displays yield components i.e. seed number, TSW, and seed yield for the two categories of seeds collected from and podsL≥5cm and podsL<5cm. The total seed yield (TSY, including seeds from both categories of pods) ranged from 8.71 to 9.92 g plant-1, with no significant S effect. Under LS, no significant decreases in TSY were observed in the T-modalities whereas under HS, significant decreases were observed in mod1 (-24.2% relative to HS T-control) and mod2 (-11.1% relative to HS T-control). These decreases were due to the seed yield from podsL<5cm since seed yield from podsL≥5cm remained unchanged in T-control plants (Table 1). The total seed numbers were not impacted by the T-modality but a slight S-effect was observed (p<0.05), with LS values being 5% lower than HS values on average. This effect was also attributed to seeds from podsL<5cm as the number of seeds from podsL≥5cm was not impacted by S supply. The TSWs from podsL<5cm were 3.33 g and 3.22 g in the HS and LS T-controls, respectively, while the equivalent podsL≥5cm values were 3.73 and 3.5 g. For a given T-modality and a given S condition, the podsL<5cm had a lower TSW than the podsL≥5cm, although the differences were significant only under LS for mod3 and mod4 (Table 1, t-tests not shown). Under both HS and LS, no T-modality effects on the TSW were observed in either pod categories. These results confirmed that (i) seeds from podsL≥5cm had reached the onset of seed maturation and (ii) seeds developing in podsL<5cm or seeds from fertilized flowers that developed after the temperature sequences, all benefited from increased sink strength due to young pod abortion or reductions in late flowering.
In the following result sections, seed characteristics were measured solely on seeds from podsL≥5cm.