Objective:

To find benefits of plant growth regulator (PGR) treatments that improve yield and prevent lodging for wheat varieties.

Personnel:

J.A. Torrion, Eeusha Nafi, Daniel Porter

Methods: 

The experiment was laid out in randomized complete block design. There were two fertility control treatments: one was T1 with a standard fertility and second was T2 with high fertility, both of which had no PGR applied. To attain the higher fertility level in T2, we added extra 40 lbs of nitrogen/A using urea. The same amount of extra nitrogen was added to T3 through T8. The detailed nutrient applied and other management information is provided in Table 1. The data were analyzed using R statistical package and the results are presented in Table 2.

 

Table 1. Management Information
Seeding date:       Sept. 22, 2020 Field Location:  R13
Julian date: 266 Harvest date: 8/12/2021
Seeding rate: 130 lbs/a Julian date: 224
Previous crop: Barley Soil type: Creston Silt Loam
Herbicide: CleansweepM (5/6/2021) Tillage: No-till
Insecticide: None Soil residual nutrient (NO3-, P, K lb/A): 51–28-604 (Fall, 2019)
Fungicide: Headline 9fl oz/a (6/11/2021) Nutrient fertilizer applied (N, P2O5, K2O lb/A): 5/5/2021 (150-0-0) (spring broadcast) Added 40lbs N/A only for treatments T2-T8

Results:   

There was no observed statistical difference of all treatments for physiological maturity, stem diameter or thickness, NDVI, number of heads per area, and test weight (Table 2).

Table 2. Mean treatment effects of the various traits measured.

The standard fertility control is designated as SF whereas, the treatments that received additional nitrogen is designated as high fertility (HF). The dates of PGR applications at stages: tiller, node, and flagleaf were May 5th, May 26th, and June 11th. The wind speed at each application was within 2-6 mph. NOTE: We inadvertently had an error in T5 treatment application. Instead of Palisade, the test PGR was applied instead.

Treatments & rates of PGR on stages: tiller - node - flagleaf PM HT Stem d Lodging NDVI Heads Yield Test Weight TKW Protein
    (Julian) (in) (mm) (%)   (no/ft2) (bu/A) (lbs/bu) (g) (%)
T1 PGR-0-0-SF 204 35.8 3.4 2.5 0.8 71.3 127.8 61.2 40.4 10.4
T2 PGR-0-0-HF 206 36.3 3.5 5.0 0.8 76.5 138.2 61.3 40.5 11.3
T3 PGR-0-25-0-HF 208 31.9 3.4 1.2 0.82 77.5 134.0 60.6 38.3 11.1
T4 PGR-0-0-25-HF 206 34.2 3.4 0.0 0.81 68.5 138.7 61.2 39.4 11.4
T5 PEC-0-14.4-0-HF 206 34.2 3.4 0.0 0.81 72.5 135.4 61.1 38.9 11.4
T6 PGR-0-14-11-HF 207 32.8 3.3 0.0 0.82 69.5 132.3 61.0 38.2 11.5
T7 PGR-14-11-0-HF 208 33.1 3.4 0.0 0.82 72.3 131.4 61.0 38.7 11.3
T8 PGR-14-0-11-HF 207 33.5 3.4 0.0 0.82 72.3 133.8 61.1 38.5 11.5
MEAN   206 34.0 3.4 1.1 0.81 72.5 134 61.1 39.1 11.3
CV%   1.0 3.2 5.0 223.7 2.8 16.2 4.3 0.4 2.4 2.7
LSD   2.7 1.6 0.3 3.6 0.03 17.0 8.4 0.3 1.4 0.4
PR>F   ns <0.001 ns 0.04 ns ns 0.04 0.03 0.01 <0.001
PM, physiological maturity; HT, plant height; Stem d, stem diameter or thickness; NDVI, normalized difference vegetation index. TKW, thousand kernel weight; ns, not significant.