Abstract
Plant growth regulators (PGRs) are widely used for lodging control in winter wheat (Triticum aestivum L.) grown at high N rates. Although the introduction of semi-dwarf wheat cultivars had largely solved the problem of lodging, evidence was already accumulating that the timely application of a growth retardant such as chlormequat (CCC) or ethephon could increase the grain yield of wheat, by the alteration of dry matter partitioning independently of any control of lodging. A field experiment was conducted the during 2004-5 growing season at the experimental farm of the College of Agriculture, Shiraz University (Shiraz, Iran,) located at Badjgah. The design of the experiment was a randomized complete block with treatments arranged as split plot with four replicates. Nitrogen levels (0, 100 and 200 kg ha -1 ) were the main plots. The N was applied as Urea (46% N), half at the time of stem elongation and the other half at onset of flowering. The PGR treatments included CCC at 2.20 kg ha -1 applied at Zadoks growth stage (ZGS) 25, ethephon at 0.28 kg ha -1 at Zadoks growth stage (ZGS) 39, and controls (without any PGR) were assigned to sub-plots. The results showed that both PGR treatments reduced the plant height and this reduction played an important role in the increase of the grain yield in wheat, via the alteration of dry matter partitioning into the spikes. However, CCC at 2.20 kg ha -1 applied at ZGS 25 increased the grain yield (8.9 t/ha) significantly, compared to the ethephon (8.2 t ha -1 ) and control (7.2 t ha -1 ) treatments; the highest grain (8.9 t ha -1 ) yield was obtained at 200 kg ha -1 N and 2.20 kg ha -1 CCC application. The beneficial interactive effects of PGRs and nitrogen rates on winter wheat yield are worthy of further exploration.
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Claims 4
Claim · model-written summary
CCC at 2.20 kg/ha applied at ZGS 25 significantly increased wheat grain yield (8.9 t/ha) compared with ethephon and control in a field experiment.
- Taxon
- wheat
Triticum aestivumt0 - Material
- cv. Shirazt0
- Treatment
- CCC at 2.20 kg ha -1 applied at ZGS 25e1
- Outcome
- grain yielde1
- Direction
- increasede1
- Value
- 8.9 t/hae1
- Comparator
- controle1
- Setting
- field experimente2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
t0“Effects of nitrogen fertilization and plant growth regulators (PGRs) on yield of wheat (Triticum aestivum L.) cv. Shiraz”
e1“CCC at 2.20 kg ha -1 applied at ZGS 25 increased the grain yield (8.9 t/ha) significantly, compared to the ethephon (8.2 t ha -1 ) and control (7.2 t ha -1 ) treatments”
e2“A field experiment was conducted the during 2004-5 growing season”
Claim · model-written summary
Both PGR treatments reduced wheat plant height.
- Taxon
- wheat
Triticum aestivumt0 - Treatment
- PGR treatmentse3
- Outcome
- plant heighte3
- Direction
- reducede3
- Comparator
- controls (without any PGR)e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
t0“Effects of nitrogen fertilization and plant growth regulators (PGRs) on yield of wheat (Triticum aestivum L.) cv. Shiraz”
e3“The results showed that both PGR treatments reduced the plant height and this reduction played an important role in the increase of the grain yield in wheat, via the alteration of dry matter partitioning into the spikes”
e4“controls (without any PGR) were assigned to sub-plots”
Claim · model-written summary
The height reduction by PGRs is associated with higher wheat grain yield through altered dry matter partitioning into the spikes.
- Taxon
- wheat
Triticum aestivumt0 - Organ / stage
- spikese3
- Treatment
- PGR treatmentse3
- Outcome
- grain yielde3
- Qualifier
- via the alteration of dry matter partitioning into the spikese3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
t0“Effects of nitrogen fertilization and plant growth regulators (PGRs) on yield of wheat (Triticum aestivum L.) cv. Shiraz”
e3“The results showed that both PGR treatments reduced the plant height and this reduction played an important role in the increase of the grain yield in wheat, via the alteration of dry matter partitioning into the spikes”
Claim · model-written summary
The highest wheat grain yield (8.9 t/ha) was obtained at 200 kg/ha N with 2.20 kg/ha CCC.
- Taxon
- wheat
Triticum aestivumt0 - Treatment
- 200 kg ha -1 N and 2.20 kg ha -1 CCC applicatione5
- Outcome
- yielde5
- Direction
- higheste5
- Value
- 8.9 t ha -1e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
t0“Effects of nitrogen fertilization and plant growth regulators (PGRs) on yield of wheat (Triticum aestivum L.) cv. Shiraz”
e5“the highest grain (8.9 t ha -1 ) yield was obtained at 200 kg ha -1 N and 2.20 kg ha -1 CCC application”
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