AAC Hodge (BW1069) is a hollow-stemmed, awned and high yielding Canada Western Red Spring (CWRS) wheat cultivar suited to the growing conditions in Western Canada. AAC Hodge was 6% higher yielding than AAC Viewfield, the highest yielding check in the Central Bread Wheat Cooperative (CBWC) registration trials (2017–2019). Within the same test, AAC Hodge was 16% higher yielding than Carberry. AAC Hodge matured 1 d earlier than Carberry and 2 d later than Unity; Unity is the earliest maturing check in the eastern prairie growing conditions. AAC Hodge was 7 cm shorter with better lodging resistance than Unity. The lodging score for AAC Hodge was lower than the mean of the checks. The test weight of AAC Hodge was similar to the mean of the checks. Over the 3 yr of testing (2017–2019), the 1000-kernel weight of AAC Hodge was equal to, or higher than all the checks. The grain protein content of AAC Hodge was equal to that of AAC Viewfield. AAC Hodge was rated moderately resistant to Fusarium head blight (FHB; Fusarium graminearum Schwabe) and resistant to leaf rust (Puccinia triticina Erikss.), stripe rust (Puccinia striiformis Westend), stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn), and common bunt [Tilletia caries (DC) Tul. & C. Tul.]. AAC Hodge ranged from resistant to moderately susceptible for its reaction to the Ug99 family of stem rusts. AAC Hodge was resistant to orange wheat blossom midge (OBWM) (Sitodiplosis mosellana Géhin). AAC Hodge was registered under the CWRS class.
Introduction
Wheat (Triticum aestivum L.) is grown across the globe as a principle component of the human diet and animal feed. The Food and Agriculture Organization (FAO) data reports the 2020–2021 global gross wheat production at 777 million metric tonnes from a harvested area of 225 million hectares (FAOSTAT 2021). Canada ranked 5th amongst the wheat producing nations with 35 million tonnes of wheat produced from a cropped area of 9.5 million hectares in 2020 (FAOSTAT 2021). Canada, known for its premium quality red spring wheat, is the second largest exporter of wheat valued at 6.3 billion dollars (Grains Canada 2021). A recent report by Toth et al. (2019) shows a steady yield increase in Canada over the past three decades. This increase in yield is critical for sustaining increasing demand for wheat, which provides 16% of the calories and 25% of the protein in human diet globally (Braun et al. 2010). The CWRS class of bread wheat constituted 69% of the total western Canadian acres in 2020 ( www.grainscanada.gc.ca). Due to its steady yields, optimum disease resistance, and excellent milling and baking attributes, CWRS wheat is the preferred cereal rotation crop across the Canadian Prairies. Canadian farmers manage good returns on their wheat due to the high market demand and the export of CWRS wheat from Canada. The new and improved field ready cultivars facilitate increased agricultural productivity and marketability under sustainable production systems.
AAC Hodge is a hard red spring wheat cultivar developed by the Agriculture and Agri-Food Canada (AAFC), Brandon Research and Development Centre, Brandon, Manitoba, Canada. It was registered by Variety Registration Office of the Canadian Food Inspection Agency under the registration number 9099. AAC Hodge is best adapted to the Canadian Prairie growing conditions and is protected by Plant Breeder’s Rights Application Number 20-10257 effective 2020-06-04.
Pedigree and Breeding Methods
AAC Hodge is derived from a cross of BW430/BW897. The female parent BW430 was derived from a cross between Alsen (Frohberg et al. 2006) and BW313. Alsen (ND 674//ND 2710/ND 688) was released by the North Dakota Agricultural Experiment Station in 2000. The line BW313 was derived from a cross between RL4763*2/Howell. The male parent BW897 was an advanced line derived from a cross with Prodigy (Graf et al. 2003) crossed twice with Alsen (Prodigy/2*Alsen). Alsen was developed by incorporating the FHB resistance from Sumai 3 into an adapted background that had good stem and leaf rust resistance, yield, and quality characteristics (Frohberg et al. 2006). Prodigy, a hard red spring wheat, was developed by Saskatchewan Wheat Pool Research and Development. Prodigy is resistant to stem rust and leaf rust and has strong straw (Graf et al. 2003). This complex cross was developed to generate a high-yielding CWRS wheat variety adapted to the eastern Canadian prairies, with broad resistance to leaf and stem rust, FHB, and resistance to the OBWM. AAC Hodge tested positive for markers linked to genes Lr14a, Lr16, Lr23, Lr34, Sr11, UtBW278, Fhb1, Fhb-5AS, Sm1, PinB, Sbm, SNN-1, 7BxOE, Wx-B1, PPd-D1-2, and RhtB (Toth et al. 2019).
AAC Hodge was developed using the modified pedigree breeding method. The final cross for AAC Hodge was made at the AAFC, Cereal Research Centre in 2008. In 2008–2009, the F1 seeds were grown as 1.5 m rows near Leeston, New Zealand. The F2 seeds harvested from Leeston were grown near Portage la Prairie, MB as 3 m rows with 40 seeds per row. A total of 250 spikes were collected from the selected 3 m rows. The F2-derived lines were further selected based on agronomic, disease resistance, and grain quality up to the F6 generation. The F6-derived lines were then tested in advanced yield trials at multiple locations and further selections were done based on agronomic, disease and grain/flour quality attributes. Finally, the line BJ08B-NP-24-NGNB-10-N was tested in the CBWC registration trials as BW1069 for 3 yr (2017–2019). A detailed description of the breeding history and breeder seed development is given in Table 1.
Table 1.
Population size and activities at each generation leading to the development of AAC Hodge (BW1069) hard red spring wheat.
Agronomic data collection
The CBWC registration trial consisted of 30 entries tested at up to 13 locations within Manitoba and Saskatchewan using a rectangular lattice design with 6 blocks as 5 entries per group and 3 replicates. The agronomic check cultivars included in the CBWC were Unity (BW362) (Fox et al. 2010), Glenn (ND747) (Mergoum et al. 2006), Carberry (BW874) (DePauw et al. 2011) and AAC Viewfield (Cuthbert et al. 2019). The yield data from all three replicates were collected from all 13 locations. The final plot yields at similar moisture content were converted to yield per unit area (kg·ha−1). Days to maturity was recorded as days from seeding to when seeds resisted denting by fingernail (16%–18% moisture), and maturity data from all the replicates were collected multiple times per week. The plant height was measured in centimeters from the ground to top of the spikes, excluding the awns after the stem extension had ceased. Lodging was recorded on a 1–9 scale where 1 was upright and 9 was completely lodged. Test weight was measured on cleaned grain samples and reported as kilograms per hectolitre. Kernel weight was measured using a minimum of 200 undamaged kernels and recorded as grams per 1000-kernels.
Disease testing
The line BW1069 was evaluated for disease reaction to leaf, stem, and stripe rust, FHB, common bunt, loose smut, and OBWM in CBWC trials between the years 2017–2019. Field nurseries inoculated with either a macroconidial spore suspension (University of Manitoba, Carman) or corn spawn [Morden Research and Development Centre, Manitoba (MRDC)] inoculum, with an equal proportion of 4 isolates HSW-15-27 (15 ADON), HSW-15-39 (3 ADON), HSW-15-57 (15 ADON), HSW-15-87 (3 ADON) of Fusarium graminearum Schwabe, was used to evaluate tolerance to FHB. The visual rating index (VRI = % incidence × % severity/100) was recorded as described by Gilbert and Woods (2006) and the ISD (Incidence Severity DON) rating was calculated as (0.2 × mean incidence + 0.2 × mean severity + 0.6 × mean DON). Reactions to leaf (Puccinia triticina Erikss.) and stem rust (Puccinia graminis Pers. f.sp. tritici Eriks. & E. Henn) diseases were assessed using the modified Cobb scale (Peterson et al. 1948) in inoculated field nurseries at the MRDC. Experiments were also conducted in the greenhouse to evaluate seedling reactions to six leaf rust races, MBDS (12-3), MGBJ (74-2), TJBJ (77-2), TDBG (11-180-1), TDBG (06-1-1) and MBRJ (128-1) (McCallum and Seto-Goh 2006), and six stem rust races, TMRTF (C10), RKQSC (C63), TPMKC (C53), RTHJF (C57), QTHJF (C25), and RHTSC (C20) (Fetch 2005; Jin et al. 2008). Natural field infections were used to assess the disease severity and reaction to stripe rust (Puccinia striiformis Westend) near Lethbridge, Alberta (Randhawa et al. 2012). Common bunt [Tilletia caries (DC) Tul. & C. Tul.] resistance was recorded at the Lethbridge Research and Development Centre, Lethbridge, Alberta, Canada using a composite of races L1, L16, T1, T6, T13, and T19, and planting inoculated seed into cold soil (Gaudet and Puchalski 1989; Gaudet et al. 1993). The reaction to loose smut (Ustilago tritici (Pers.) Rostr.) was assessed by inoculating wheat spikes with a composite of races T2, T9, T10, and T39 (Menzies et al. 2003) and rating the progeny plants grown in a greenhouse from the infected seeds. The reaction to OBWM feeding damage was assessed by visually inspecting the midge damaged kernels on mature spikes. Forty-five spikes (15 spikes per replicate from three replicates) were collected per entry and were analyzed under a dissecting microscope for larval feeding damage symptoms. Based on type of damage, the entries were classified as resistant, susceptible, or undamaged.
Grain and flour quality evaluation
Evaluation of end-use quality was conducted by the Grain Research Laboratory (GRL) of the Canadian Grain Commission (CGC) in Winnipeg, Manitoba. Protein content and grade of the check cultivars were used as criteria to prepare composite samples from all test locations, which were subsequently used in tests to measure grain protein (%), flour protein (%), protein loss (%), falling number (s), α-amylase activity (amylograph; BU), clean flour yield (%), flour yield (%; 0.5% ash basis), flour ash (%), starch damage (%), farinograph properties, and dough development properties using standard analytical methods as outlined in the Prairie Recommending Committee for wheat, rye and triticale operating procedures (Prairie Recommending Committee 2021).
The data analysis was performed using AGROBASE Generation II®. The years, environments, and their interactions were treated as random effects, and cultivar as a fixed effect, and the model was used to generate means and standard errors. The least significant difference (LSD) was then calculated using the formula LSD = standard error × TINV × (1 − 0.05/2, df), where the TINV(P, df) function returns the t value corresponding with the two-tailed probability P (P value) and the specified degrees of freedom (df). The LSD was used to analyze the improvements of AAC Hodge over the check cultivars. The end-use quality data are non-replicated observations within years.
Performance
The 2017–2019 CBWC registration trials had Unity (BW362) (Fox et al. 2010), Glenn (ND747) (Mergoum et al. 2006), Carberry (BW874) (DePauw et al. 2011) and AAC Viewfield (Cuthbert et al. 2019) as the recommended checks. Based on 33 site-years of testing over 3 yr, AAC Hodge was higher yielding than Glenn (17%), Carberry (16%), AAC Viewfield (6%) and Unity (11%) (Table 2).
Table 2.
Yield (kg·ha−1) of AAC Hodge (BW1069) and check cultivars in the Central Bread Wheat Cooperative, 2017–2019.
AAC Hodge matured 1 d earlier than Carberry and was the same or earlier than all checks except Unity (Table 3). AAC Hodge was 7 cm shorter in height and had better lodging resistance compared with Unity. AAC Hodge had a similar test weight to the checks and higher or equivalent kernel weight to the checks. The grain protein content of AAC Hodge was equivalent to AAC Viewfield but 0.1% lower than Unity (Table 3).
Table 3.
Summary of agronomic traits of AAC Hodge (BW1069) and check cultivars in the Central Bread Wheat Cooperative, 2017–2019.
AAC Hodge had strong resistance to diseases prevalent in the eastern Canadian Prairies. AAC Hodge was rated moderately resistant to FHB by the disease evaluation team of the Prairie Grain Development Committee. Over 3 yr of testing (2017–2019), AAC Hodge expressed moderately resistant reactions to FHB at the Carman and Morden, Manitoba locations (Table 4). It had lower or equivalent mean deoxynivalenol (DON) levels than all checks in the inoculated nurseries (Table 4). AAC Hodge was resistant to the prevalent races of leaf, stem and stripe rust (Table 5). It was also rated resistant to common bunt (Table 6). Based on 3 yr of data, AAC Hodge is resistant to OWBM based on phenotypic data on midge tolerance and the presence of Sm1 gene marker (Table 6).
Table 4.
Fusarium head blight VRIa, DON, ISDb and FDKc for AAC Hodge (BW1069) and check cultivars in the Central Bread Wheat Cooperative, 2017–2019.
Table 5.
Rust disease severities and ratings of AAC Hodge (BW1069) and check cultivars in the Central Bread Wheat Cooperative, 2017–2019.
Table 6.
Bunt, smut, leaf spot and midge ratings of AAC Hodge (BW1069) and check cultivars in the Central Bread Wheat Cooperative, 2017–2019.
Grain and flour quality attributes of AAC Hodge were tested by the Grain Research Laboratory in Winnipeg, Manitoba, Canada. End-use quality assessment using the established methods (AACC 2000) was performed on a composite sample formulated from trial locations, with grain samples representative of the best hard red spring wheat grades available. A pre-determined quantity of final grain was made up by varying the proportion of grain from each location to achieve a final protein concentration approximating the average for the crop in the given year. AAC Hodge met the milling and baking performance of the CWRS class of wheat. The grain protein was the same as AAC Viewfield and lower than the other checks (Table 7). The protein loss of AAC Hodge was similar to the checks. Flour protein (%) and falling number (s) were similar to Unity. The peak viscosity measured by the amylograph (BU) was higher or similar to all of the checks. The clean flour yield (%) was higher than all of the checks. Flour ash (%) was equivalent or higher than the checks. Starch damage was higher than all of the checks except Glenn in 2018. Flour yield (0.5% ash, %) was equivalent or lower than the checks (Table 7). Water absorption measured on the farinograph directly relates to the amount of bread that can be produced from a given weight of wheat flour. The farinograph absorption was lower than the checks, and dough stability was higher than the checks (Table 8). The loaf volume (cm3) for AAC Hodge was similar to AAC Viewfield and lower than Glenn. The loaf top ratio was similar to Glenn and higher than the other checks (Table 8).
Table 7.
Wheat and flour analytical dataa for AAC Hodge (BW1069) and check cultivars from the Central Bread Wheat Cooperative (2017–2019).
Table 8.
Dough properties and baking qualities for AAC Hodge (BW1069) and check cultivars from the Central Bread Wheat Cooperative (2017–2019).
Other Characteristics
The morphological characteristics were recorded using experimental field plots grown in 2019 and 2020 at Saskatoon, SK. The characteristics were compared with two reference varieties AAC LeRoy (Kumar et al. 2019a) and AAC Magnet (Kumar et al. 2019b) for morphological distinctness.
Seedling characteristics
Coleoptile colour: White to slightly purple.
Juvenile growth habit: semi-prostrate to intermediate.
Seedling leaves: medium green, glabrous.
Adult plant characteristics
Growth habit: intermediate.
Flag leaf attitude: intermediate to drooping.
Flag leaf: medium green, medium-recurved, glabrous sheath and blade, auricles absent, pronounced waxy blade.
Culm: straight, glabrous and weak-medium waxy upper internode.
Spike characteristics
Shape: erect and parallel sided.
Length: medium.
Density: medium.
Attitude: erect.
Colour: light brown maturity.
Awns: awned.
Maintenance and Distribution of Pedigreed Seed
Breeder Seed of AAC Hodge was produced using 250 random spikes from a rogued increase plot grown near Rosebank, MB, in 2017. Two hundred and fifty lines were grown as an isolated group of 1 m head rows in 2018 near the Brandon Research and Development Centre. Head rows which lacked uniformity or had poor seed production were discarded. In 2019, a 15 m row was grown from each of the 225 selected isolation rows at the Indian Head Seed Increase Unit. Prior to bulk harvesting the breeder rows, 23 rows were discarded. The remaining uniform plots were inspected and bulk harvested, producing approximately 400 kg of Breeder Seed. Multiplication and distribution of all other pedigreed seed classes will be handled by FP Genetics Inc., 426 McDonald Street, Regina, SK S4N 6E1, Canada; phone: 306-791-1045; fax: 306-791-1046; website: https://www.fpgenetics.ca/contact.php; email: info@fpgenetics.ca. AAC Hodge is a OBWM resistant variety and to maintain the effectiveness of the Sm1 gene against the insect, the certified seed will include AAC Hockley as a 10% interspersed susceptible refuge.
Author Contributions
Drs. S. Kumar and S. L. Fox performed selections and progression of lines to finally select AAC Hodge (BW1069). Dr. S. Kumar analysed the registration trial data, generated varietal identification data for Variety Registration and Plant Breeders’ Rights including the necessary documentation,and wrote the manuscript. The other authors contributed agronomic and disease evaluation data from the registration trials.
Acknowledgements
Financial support from the Western Grains Research Foundation is gratefully acknowledged. The authors also appreciate the contributions of: D. Niziol (Cereal Quality Lab, AAFC, Winnipeg) and Dr. Fu (Grain Research Laboratory, Canadian Grain Commission, Winnipeg, MB) for end-use suitability analysis; Dr. Brule-Babel (University of Manitoba), Dr. Burt (Ottawa Research and Development Centre, Ottawa), and Dr. Foster (Charlottetown Research and Development Centre, Charlottetown) for assessing reaction to FHB; and Dr. Naeem, (AAFC-Seed Increase Unit, Indian Head, SK) for production of Breeder Seed; C. Workman, J. Hovland, L. Powell, S. Pandurangan, C. Lesiuk, B. Cormack, R. Smith, C. Babel, T. Ward, V. Dyck, J. Rempel, P. Cormack, E. Morrison, S. Zatylny, S. Keeble, A. Deng, J. Welbourne and all the members of the wheat genetic enhancement group at BRDC.
