Effects of Foliar Applied Sulfur and Commercial Growth Regulators in Wheat

During the year 1999, two glasshouse experiments (Experiments 1 and 2) were conducted at the University of Wales Aberystwyth, UK to investigate the effects of foliar applied sulfur (S) in wheat in terms of its potential as a growth regulator and to compare the effects with that of commercial growth regulators, chlormequat (CC) and gibberellic acid (GA₃). In Experiment 1, the grain yield was unaffected by sulfur or growth regulator treatments. Similarly, there were no differences in the number of fertile ears at maturity. Stem characteristics were not affected with S application, but CC application reduced the average stem length; although, it did not affect the unit stem weight. The GA₃ did not change stem characteristics. In Experiment 2, the grain yield was significantly reduced by CC. Stem characteristics were not affected by S application while application of CC brought about a significant reduction in the stem length and increased the unit stem weight. Applied CC reduced the stem length irrespective of the timing of its application, maintaining its versatility as a growth regulator. Grain Nitrogen (N) concentration was apparently increased; while in Experiment 2 plant N-uptake occurred significantly by foliar S application at 20 kg/ha. The work emphasized the potential role of S in a low-input wheat production system or in organic wheat production systems.