Objective:       

To evaluate winter wheat height response to foliar applied abscisic acid.

Results:           

Plant height is directly related to lodging, which reduces grain quality and yield. This study was designed to determine the effect of abscisic acid (ABA) on reducing plant height.

The study was established as a randomized complete block with three replications. Yellowstone winter wheat was planted at 80 lb/A in 7 inch rows on September 29, 2014. The factorial treatment arrangement consisted of abscisic acid applied at three different rates and at two different growth stages. The treatment was applied at 0.078 lb ai/A, 0.156 lb ai/A, and 0.624 lb ai/A on May 7th and May 20th, 2015 when the wheat crop was at the two node or flag leaf stage of growth, respectively.

No significant effect was observed for plant height or lodging. However, the application of abscisic acid did have an effect on heading date and test weight (Table 2). Abscisic acid treatments had no effect on heading date when applied at the two node stage of growth.  However, when abscisic acid was applied at the flag leaf stage, heading occurred earlier as the application rate increased.  As a result, the earliest heading date was observed when the highest rate was applied at flag leaf.  At the same time, the highest test weight was associated with this same treatment.

Summary:       

It may be possible that the early heading allowed the plant to initiate grain filling before drought conditions became severe, which in turn improved test weight.  However, abscisic acid is known to impact plant water use under stressful conditions by regulating stomatal apertures. In either case, these results indicate that foliar applications of ABA may provide benefits with respect to grain quality.

 

Table 1. Materials and Methods - Winter Wheat Abscisic Acid   
Seeding Date: 9/29/2014 Harvest Date: 7/30/2015
Julian Date: 272 Julian Date: 211
Seeding Rate: 80 lbs/A Soil Type: Creston SiL
Previous Crop: Spring Wheat Soil Test: 29-10-158
Tillage: Conventional Fertilizer: 9-40-10, 0-0-62,130-0-0 TD
Irrigation: None Herbicide: Huskie Complete 13.7 oz/A

 

Table 2. Agronomic effect of foliar applied abscisic acid on winter wheat       
Rate of ConTego HD HT YLD1 PRO2 TWT1 TKW1 FN
lb ai/A Julian in bu/A % lb/bu g sec
Non-treated check 152.7 43.0 149.1 11.4 61.2 39.6 417.8
  Two nodes
0.078 152.7 41.7 151.5 11.1 61.6 41.0 413.2
0.156 152.7 42.0 149.1 11.4 61.5 40.0 426.2
0.624 152.0 41.3 147.2 11.6 60.6 39.7 435.4
  Flagleaf
0.078 153.0 42.0 150.2 11.3 61.4 40.7 417.1
0.156 152.3 41.0 134.3 11.6 60.5 38.5 432.2
0.624 151.7 41.7 148.3 11.3 61.9 41.1 421.5
Mean 152.4 41.8 149.2 11.4 51.4 40.1 423.3
CV 0.3 1.8 5.2 5.2 0.5 3.8 4.8
LSD P=.05 0.8 ns ns ns 0.4 ns ns
Pr>F 0.0314 0.1360 0.9872 0.9230 0.0203 0.4205 0.7957
HD: heading, HT: height, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernel weight, FN: falling number, ns: nonsignificant       
¹adjusted to 13% moisture, ²adjusted to 12% moisture       

 

Table 3. Main effect of application timing
  HD HT YLD¹ PRO² TWT¹ TKW¹ FN
Timing Julian in bu/A % lb/bu g sec
two node 153 42.0 149.2 11.4 61.2 40.1 423.2
flag leaf 152 41.9 145.5 11.4 61.2 40.0 422.2
LSD ns ns ns ns ns ns ns
Pr>0.05 0.4226 0.8075 0.3067 0.9715 0.9415 0.7759 0.9068
HD: heading date, HT: height, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernel weight, FN: falling number, ns: nonsignificant
¹adjusted to 13% moisture, ²adjusted to 12% moisture

 

Table 4. Main effect of treatment rate
Rate of ConTego HD HT YLD¹ PRO² TWT¹ TKW¹ FN
lb ai/A Julian in bu/A % lb/bu g sec
Non-treated check 153 43.0 149.1 11.4 61.2 39.6 417.8
0.078 153 41.8 150.9 11.2 61.5 40.9 415.2
0.156 153 41.5 141.7 11.5 61.0 39.2 429.2
0.624 152 41.5 147.7 11.4 61.2 40.4 428.5
LSD ns ns ns ns ns ns ns
Pr>0.05 0.0848 0.1063 0.5344 0.7843 0.2392 0.4618 0.4335
HD: heading date, HT: height, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernel weight, FN: falling number, ns: nonsignificant

¹adjusted to 13% moisture, ²adjusted to 12% moisture

 

Table 5. Effect of application timing and treatment rate
  HD HT YIELD¹ PRO² TWT¹ TKW¹ FN
Timing Julian in bu/A % lb/bu g sec
  Non-treated check
two node 153 43.0 149.1 11.4 61.2 39.6 417.8
flag leaf 153 43.0 149.1 11.4 61.2 39.6 417.8
  0.078 lb ai/A
two node 153 41.7 151.5 11.1 61.6 41.0 413.2
flag leaf 153 42.0 150.2 11.3 61.4 40.7 417.1
  0.156 lb ai/A
two node 153 42.0 149.1 11.4 61.5 40.0 426.2
flag leaf 152 41.0 134.3 11.6 60.5 38.5 432.2
  0.624 lb ai/A
two node 152 41.3 147.2 11.6 60.6 39.7 435.4
flag leaf 152 41.7 148.3 11.3 61.9 41.1 421.5
LSD ns 0.6 ns ns 1.1 ns ns
Pr>0.05 0.4547 0.0293 0.4486 0.8263 0.0452 0.4392 0.8542
HD: heading date,HT: height, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernel weight, FN: falling number
¹adjusted to 13% moisture, ²adjusted to 12% moisture