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To provide wheat growers in south central Montana with a reliable, unbiased and up-to-date source of information that will permit valid comparisons among improved winter wheat varieties. This information should help winter wheat producers in south central Montana select varieties best suited to their particular area and growing conditions.
The 2021 off-station winter wheat trials were established under irrigation at Huntley and under dryland conditions near Molt, Fort Smith, Hardin, Hysham, and Rapelje under no-till, chemical fallow conditions (Fig. 1). Each trial contained 25 winter wheat cultivars (17 commercial, 8 experimental), and was planted using a partially-balanced lattice design under dryland and irrigated conditions with three replications. All entries were seeded at approximately 1 million seeds per acre under dryland conditions (~60 lb/a) and 1.5 million seeds per acre under irrigation (~90 lb/a). Dryland test plots consisted of a 16-foot, 4-row plot with 15-inch row spacing. Irrigated test plots consisted of a 16-foot, 7-row plot with 7-inch row spacing. All rows of each harvested test plot were trimmed 36 inches and harvested using a plot combine. Recorded grain yields were adjusted to 13% grain moisture content, and are reported in bushels per acre based on a 60 pound standard bushel weight. Two year (2020-21) and three year (2019-21) yield averages are provided for cultivars tested during previous years. Test weight (pounds per bushel) and grain
Recorded grain yields were adjusted to 13% grain moisture content, and are reported in bushels per acre based on a 60 pound standard bushel weight. Two year (2020-21) and three year (2019-21) yield averages are provided for cultivars tested during previous years. Test weight (pounds per bushel) and grain moisture content (percent) were obtained for each plot using a Dickey-john GAC 2100 grain analyzer. Grain protein content (percent) was determined by near-infrared reflectance for each harvested sample, and adjusted to 12% grain moisture content. Plant height was measured in inches from the soil surface to the top of the head, excluding the awns if present. Days to heading were determined from January 1st (Julian) and corresponding calendar dates are also presented. Information pertaining to the specific cultural management of each study site is listed at the bottom of their respective data tables.
The 2021 winter wheat test sites had below average rain or snow accumulation during winter months except in October 2020. Over 2 inches of precipitation in October provided good soil moisture conditions for winter wheat emergence. While precipitation during the months of March and April provided some moisture for winter wheat early stand establishment. However, below average precipitation was observed throughout the 2021 winter wheat growing season particularly during grain filling period. Below average rainfall in June and July (0.4 and 0.1 inches respectively) coupled with higher than normal temperatures resulted in heat and drought stress during grain filling period that reduced winter wheat yield. The 2021 growing season was one of the hottest year on record. The average temperature during June and July was 6.4 and 5.1 °F above the long-term average. Winter wheat crop failure or severe yield loss occurred under dryland production, though some yield reduction was observed under irrigation due to heat stress.
Irrigated winter wheat trial at SARC near Huntley had good stand establishment and no lodging was observed this year. Grain yield averaged 110 bu/acre and ranged from 93 bu/acre for ‘Judee’ to 121 bu/acre for ‘LCS Jet’ (Table 1). Cultivars ‘AAC Wildfire’ and ‘Judee’ had the lowest yield at this site that was statistically lower than the yield of highest yielding cultivar. Test weight values under irrigated conditions averaged 62.4 lb/bu and all entries produced test weight over 60 bu/ac. Grain protein content averaged 13.2 percent and ranged from 12.o to 14.1 percent. Two- (2020 and 2021) and three-year (2018 and 2020-21) average yield for winter wheat varieties tested at Huntley was 113 and 111 bu/acre respectively. LCS Jet was the highest yielding cultivar averaged over the past three-year.
Drought and heat stress caused winter wheat yield reduction under dryland conditions at Rapelje in 2021. Grain yield averaged 23 bu/acre (Table 2), about half than the winter wheat yield observed at this site in 2020. Grain yield ranged from 12 bu/acre for ‘MTCL1737’ to 30 bu/acre for ‘Brawl CLP’. Four other entries produced yield that was statistically equal to the yield of highest yielding cultivar. Test weight was low and averaged only 57.4 lb/bu. All entries produced test weight under 60 bu/ac at this site. Grain protein was high and averaged 17.1 percent. Two year average yield for winter wheat varieties tested at Rapelje during 2020 and 2021 was 39 bu/acre. Three-year average yield 2019 through 2021 was 51 bu/acre.
Dryland winter wheat trial at Forsyth was severely affected by drought and heat stress during 2021. Winter wheat crop failure occurred and local producer at this site did not harvest the crop. However, we harvested the test plots to determined varietal response to abiotic stresses. Grain yield averaged only 2.8 bu/acre (Table 3). No additional data was collected due to the limited amount of grain harvested.
Average yield under dryland conditions at Molt was 38 bu/acre (Table 4). Yield ranged from 32 bu/acre for ‘MTCL1737’ to 42 bu/acre for ‘Keldin’. Test weight averaged 62.2 lb/bu. All entries had test weight of 60 lb/bu or higher except ‘Byrd CLP’. Grain protein content averaged 13.3 percent and ranged from 12.5 percent to 14.3 percent. Two-year (2020 and 2021) and three-year (2019-21) averaged yield for winter wheat varieties tested at Molt was 61 and 60 bu/acre respectively. Keldin was the highest yielding cultivars at this location averaged over the past three-year.
Grain yield under dryland conditions at Fort Smith in 2021 averaged 32 bu/acre (Table 5). Grain yield ranged from 22 bu/acre for MTCL1737 to 43 bu/acre for Keldin. Brawl CLP also produced yield that was statistically equal to the yield of highest yielding cultivar. Test weight was low and averaged only 56.6 lb/bu. All entries produced test weight under 60 bu/ac at this site. Grain protein was high and averaged 16.1 percent. Two- and three-year average yield for winter wheat varieties tested at this site was 56 and 64 bu/acre respectively.
Severe drought and heat stress, particularly during the grain filling period, caused winter wheat yield loss at all dryland test sites in 2021. Below average precipitation and above average temperatures were observed throughout the winter wheat growing season. Grain yield at dryland locations averaged only 31 bu/acre and ranged from 2.8 bu/acre at Forsyth to 38 bu/acre at Molt (Table 5). Brawl CLP was the highest yielding cultivar averaged across all dryland locations in 2021 (Table 6 and 7). While LCS Jet was the highest yielding cultivar under irrigated condition (Tables 1 and 6). ‘Fourosix’ and Keldin were the highest yielding cultivars (55 bu/acre) averaged across all locations tested in 2021 growing season (Table 5 and 8). Since 2019, in experiments representing 12 location-year in southcentral Montana, Keldin was the highest yielding cultivar producing 75 and 76 bu/acre over the past two- and three-year respectively across all dryland and irrigated locations (Tables 8).