Assessing the Pre-Harvest Sprouting Reaction of Spring Wheat Varieties

James A. Anderson, Dept. of Agronomy and Plant Genetics, University of Minnesota

Research Question

Our objective was to assess the pre-harvest sprouting reaction of spring wheat varieties grown in Minnesota and advanced breeding lines from the University of Minnesota.

Results

Samples from the 2004 St. Paul nursery had more sprouting than had been seen in previous years. The variety HJ98 was notably more susceptible to sprouting damage in 2004 than in previous seasons (see Table 1 in Appendix). Also, experimental lines with HJ98 as one of their parents (including MN97803-A) generally fared poorly in the 2004 St. Paul test. Overall, most hard red spring wheat varieties have high levels of grain dormancy and resist pre-harvest sprouting (PHS), even when appropriate environmental conditions exist. However, there are significant differences in varietal response with 'Ingot' being particularly susceptible to pre-harvest sprouting. Sprouted wheat will also have low falling numbers. However, low falling numbers are possible without evidence of sprouting. An additional 145 experimental lines were tested for PHS at the St. Paul location only. Forty-three of these lines had unacceptably low resistance to pre-harvest sprouting (data not shown). Six of the 145 experimental lines were white-seeded, but only one of these showed acceptable levels of PHS resistance.

Application/Use

Pre-harvest sprouting reaction is another factor that growers should consider when selecting varieties. These ratings will be in included in the 2004 edition of Minnesota Varietal Trials Results.

Materials and Methods

Ten spikes from each of two replications were harvested at physiological maturity from yield plots of our variety trial at Crookston and a PHS nursery containing 210 Univ. of MN experimental lines and varieties at St. Paul. The yield trial consisted of 25 named varieties and 16 experimental lines. The loss of green color from the pigment strand in the kernel crease was used as a proxy for physiological maturity (Hanft and Wych, 1982). This required sampling each location on 2 (Crookston) or 3 days (St. Paul) to ensure each variety was harvested at the same stage of maturity. Harvested spikes were air-dried for 5 days under ambient conditions and frozen at _20C (to preserve the samples' state of dormancy). Five spikes of each variety were placed in a dew chamber in each run. Therefore, 4 total runs were needed to test all 20 spikes from each location. After seven days in the dew chamber, individual spikes were rated on a scale of 1 (no evidence of sprouting) to 10 (extensive sprouting throughout the spike) as described by McMaster and Derea (1976). This rating system takes into account both the number of sprouted kernels observed and the rate at which they germinate. Sprout scores for individual plots were calculated by averaging the scores for the 5 spikes. Spikes with evidence of fungal infection were discarded.

Economic Benefit to a Typical 500 Acre Wheat Enterprise

Choice of variety is one of the most important decisions growers make each year. Many growers received large discounts at the elevator in 2002 due to sprouted grain or low falling numbers. Sprouted grain and low falling numbers were a concern in 2004 due to the wet harvest-time conditions. Therefore, selecting varieties with good resistance to pre-harvest sprouting will reduce the chances of diminished grain quality and discounts due to sprouting.

Related Research

The USDA/ARS Hard Red Spring & Durum Wheat Quality Laboratory in Fargo began routine testing of varieties and experimental lines for falling number beginning with the 2002 crop. This will provide additional data in cases where there is some alpha-amylase (an enzyme involved in the early stages of seed germination) activity prior to harvest. This data will be published in the 2004 Varietal Trials Extension publication. North Dakota State University routinely collects pre-harvest sprouting data, so there is a possibility of sharing and combining information.

Publications

Anderson, JA, G. Llinkert, and R. Fuentes. 2003. Hard Red Spring Wheat. In Minnesota Varietal Trials Results, University of Minnesota Extension Service

Table. 1 Pre-harvest sprouting reaction of 25 hard red spring wheat varieties and 4 experimental lines. 

Line	2004 Ave. 1.2	3 yr Ave. 1.3	Rating 4
Hanna	1.0	1.09	Resistant
MN95229-A	1.43	1.28	Resistant
Steele - ND	1.47	1.29	Resistant
Parshall	1.13	1.31	Resistant
Dapps	1.15	1.32	Resistant
Alsen	1.13	1.34	Resistant
Norpro	1.43	1.38	Resistant
MN00261-4	1.56	1.48	Resistant
Marshall	1.00	1.55	Resistant
Knutson	1.50	1.69	Resistant
Walworth	1.73	1.70	Resistant
Oklee	2.03	1.75	Resistant
Granite	2.02	1.78	Resistant
Oxen	1.58	1.78	Resistant
Reeder	1.53	1.80	Resistant
2375	2.43	1.83	Resistant
MN99436-6	1.80	1.84	Resistant
Briggs	1.07	1.85	Resistant
Verde	187	1.87	Resistant
HJ98	3.40	2.39	Mod. Resistant
Granger	2.62	2.58	Mod. Resistant
MN97803-A	4.08	3.29	Mod. Susceptible
Mercury	3.57	3.33	Mod. Susceptible
Ingot	3.13	4.07	Susceptible
Polaris	1310	-	-
Freyr	1.17	-	-
Saturn	1.42	-	-
Trooper	1.90	-	-
Banton	2.32	-	-
Mean	1.85	1.90
LSD	0.80	0.75