Introduction

AAC Cameron is a hard red spring wheat (Triticum aestivum L.) cultivar developed by Agriculture and Agri-Food Canada (AAFC), Cereal Research Centre (CRC), Winnipeg, Manitoba (MB). It was assigned registration number 7704 by the Variety Registration Office, Canadian Food Inspection Agency on 27 March 2015. AAC Cameron meets the end-use quality specifications of the Canada Western Red Spring (CWRS) wheat market class and is best adapted to eastern prairie Canadian growing conditions.

Pedigree and Breeding Methodology

AAC Cameron is derived from the complex cross of D1125/Alsen//BW346/3/BW370/99B60-EJ26, where Alsen (Frohberg et al. 2006) is a dark northern spring wheat variety developed at North Dakota State University and the remaining parents are hard red spring wheat breeding lines. The primary goal of this complex cross was to develop a high-yielding CWRS wheat variety adapted to western Canada, with broad resistance to leaf and stem rust, improved resistance to Fusarium head blight (FHB), and resistance to the orange wheat blossom midge (Sitodiplosis mosellana Géhin). The Alsen parent has the Chinese line Sumai-3 (PI481542) in its pedigree, which is a source of FHB resistance. The orange wheat blossom midge resistant parents Clark and RL4933 were part of the complex cross for AAC Cameron (McKenzie et al. 2002; Thomas et al. 2005). The lines BW346 (RL4802//(96MHN5295-1)BW174*2/Clark) and BW370 (N93-2260/Grandin(N96-2449)//AC Splendor) were developed to pyramid different sources of resistance to loose smut, common bunt, and leaf spot diseases. 99B60-EJ26 (BW205/RL4933) contained a recombination of Lr16 with Sm1 such that these two genes were in coupling (Thomas et al. 2005).

AAC Cameron was developed using the modified pedigree breeding method. The final cross was made in a growth cabinet in 2004, and F₁ seeds were grown under the name G0439 in a growth cabinet in 2005 at CRC in Winnipeg, MB. In 2005, six rows of F₂ progeny were grown in a nursery near Rosebank, MB in collaboration with Syngenta, Inc. Thirty-one lines of F_2:3 were grown in 2005–2006 near Palmerston North (PN), New Zealand as multi-seed hills. Selections for agronomic characteristics (height, lodging, maturity, and yield) and disease resistance (leaf rust, stem rust, and common bunt) were performed. In 2006, 12 lines of F_3:4 were grown in 1 m rows in a nursery near Portage la Prairie, MB. Selections were made based on agronomic parameters, resistance to diseases, and quality parameters (seed appearance, protein concentration, flour yield, and dough strength). In 2006–2007, five F_3:5 lines were grown near PN in 1.5 m rows and selection for agronomic characteristics and disease resistance were performed. Three F_3:6 lines were tested in 2007 in single replicate yield trials at four locations (MB: Brandon, Glenlea; SK: Saskatoon, Swift Current) and selection based on agronomic parameters, disease resistance, and quality parameters were performed. Approximately 30 spikes were advanced to the next generation. In 2007–2008, 23 lines at F_6:7 were grown near PN in 1.5 m rows and selections were made for agronomics and disease resistance. In 2008, three lines at F_6:8 were tested in single replicate yield plots at three locations (MB: Brandon; SK: Saskatoon, Melfort) and selection based on agronomics, disease resistance, and quality were performed. One line was advanced to the Central Bread Wheat “A” test in 2009. The yield test consisted of two replicates at five locations (MB: Glenlea, Brandon, Morden; SK: Indian Head, Melfort) and performance of the line was assessed on agronomic, disease, and quality parameters. The line G0439-3-NPNB-15-N at F_6:10 was advanced to Central Bread Wheat “B” test. The test consisted of three replicates at eight locations (MB: Glenlea, Brandon, Morden; SK: Indian Head, Regina, Melfort, Saskatoon; AB: Beaverlodge). The line G0439-3-NPNB-15-N was named BW485 and advanced into the Central Bread Wheat “C” (CBWC) registration test in 2011. BW485 was evaluated for three years as three replicates at 11 locations/year (MB: Glenlea, Portage la Prairie, Brandon, Morden, Souris, Dauphin; SK: Indian Head, Kamsack, Regina, Melfort, Saskatoon). The varieties McKenzie, CDC Teal, Unity, and 5603HR were used as agronomic checks for the 2011 and 2012 CBWC tests. In 2013, McKenzie and CDC Teal were replaced by Glenn and Carberry as agronomic checks.

Disease resistance tests were performed using inoculated field nurseries to determine reactions to leaf rust and stem rust at AAFC-CRC, Winnipeg using the modified Cobb scale (Peterson et al. 1948). Seedling reactions for leaf rust races MBDS (12-3), MGBJ (74-2), TJBJ (77-2), and MBRJ (128-1) (McCallum and Seto-Goh 2006) and stem rust races TMRTF (C10), RKQSC (C63), TPMKC (C53) RTHJF (C57), QTHJF (C25), and RHTSC (C20) (Fetch 2005; Jin et al. 2008) also were determined in the greenhouse. Disease severity and reaction to stripe rust (Puccinia striiformis Westend) was evaluated using natural field infection in stripe rust nurseries near Lethbridge (Randhawa et al. 2012). Tolerance to FHB was recorded at Glenlea and Carman, MB in field nurseries spray inoculated with a macroconidial spore suspension, and visual index (% incidence × % severity/100) was recorded as described by Gilbert and Woods (2006). A composite of races T2, T9, T10, and T39 was used to estimate resistance to loose smut [Ustilago tritici (Pers.) Rostr.] (Menzies et al. 2003). Resistance to common bunt was recorded at the AAFC Lethbridge Research Centre 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).

Evaluation of end-use quality was performed by the Grain Research Laboratory, Canadian Grain Commission, in Winnipeg, MB. Composite samples were prepared based on protein content and grade of the check cultivars from test locations.

Estimation of significant improvement of agronomic characteristics between AAC Cameron and the check cultivars was analysed using a least significant difference (LSD) test using the MIXED PROC module (SAS, version 9.3) with years, environments, and their interactions treated as random effects and cultivar treated as a fixed effect. The end-use quality data had no replicated observations within years.

Performance and Adaptation

The performance and adaptation data was analyzed and is presented considering changes in check cultivars in 2013. Based on 29 station years from 2011 to 2013 tests, the yield of AAC Cameron was significantly higher than all check cultivars (Table 1). The grain yield of AAC Cameron was 5.2% higher than Unity and 12.3% higher than 5603HR. AAC Cameron was one day earlier maturing than 5603HR and one day later than Unity VB in three years of testing (Table 2). Over three years of testing, AAC Cameron was taller but had similar or better lodging resistance than all checks except Glenn and Carberry, which were introduced in the third year of CBWC tests (Table 2). It had higher test weight than CDC Teal and 5603HR, and kernel weight was significantly greater compared to all checks (Table 3). AAC Cameron had improved resistance to FHB, with moderately resistant reactions and lower DON levels compared to the check cultivars (Table 4). It had moderate resistance to the prevalent western Canadian races of leaf rust, stem rust, and common bunt (Tables 5 and 6). The stripe rust, leaf spot complex, and loose smut reactions of AAC Cameron ranged between susceptible to moderately susceptible (Tables 5 and 6). During two years of testing (2012–2013), AAC Cameron had better midge resistance than all susceptible checks and more than 75% of the wheat heads tested remained undamaged by orange wheat blossom midge (Table 6).

Table 1.

Yield (kg ha^-1) of AAC Cameron and check cultivars in the Central Bread Wheat Coop from 2011–2013.

Table 2.

Summary of agronomic traits of AAC Cameron and check cultivars in the Central Bread Wheat Coop from 2011–2013.

Table 3.

Summary of agronomic traits of AAC Cameron and check cultivars in the Central Bread Wheat Coop from 2011–2013.

Table 4.

Fusarium head blight severities and ratings^a, with percent deoxynivalenol (DON) for AAC Cameron (BW485) and check cultivars in Central Bread Wheat Cooperative (2011–2013) tests.

Table 5.

Percent disease severity and ratings^a of AAC Cameron (BW485) and check cultivars to leaf, stem, and stripe rust infection in Central Bread Wheat Cooperative (2011–2013) tests.

Table 6.

Common bunt, loose smut, and leaf spot ratings^a and midge evaluations^b of AAC Cameron (BW485) and check cultivars in Central Bread Wheat Cooperative (2011–2013) tests.

End-use quality assessment by the Canadian Grain Commission determined that AAC Cameron met CWRS quality standards needed for milling and baking performance. The grain protein (%) was intermediate compared to the checks (Table 7). The farinograph absorption was similar to checks in the CWRS class of wheat (Table 7), with the exception of slightly higher flour protein loss and higher Canadian Short Process (CSP) mixing time compared to the checks.

Table 7.

Wheat and flour analytical data for AAC Cameron (BW485) and check cultivars from the Central Bread Wheat Cooperative (2011—2013) tests. End-use quality testing was performed by the Grain Research Lab of the Canadian Grain Commission on a composite sample of each cultivar.

Other Characteristics

The morphological characteristics were recorded on experimental field plots grown in 2014 at Saskatoon, SK.

Maintenance and Distribution of Pedigreed Seed

Breeder seed (F_6:11) of AAC Cameron was produced by collecting 250 random spikes from a rogued increase plot grown at Indian Head, Saskatchewan (2011). Of all the spikes collected, ten were discarded due to shrivelled seed or having few seeds. Isolation rows for breeder seed (F_6:12) were grown in 1 m rows with 10 m isolation distance from any other wheat near Glenlea, Manitoba (2012). Six lines were culled prior to harvest due to lack of uniformity. An additional 52 lines were discarded post-harvest due to low seed amounts (<30 g). One hundred and fifty-two breeder seed rows (F_6:13) were grown as 15 m rows maintaining 10 m isolation distance from other wheat at Indian Head, Saskatoon (2013) and 15 non-uniform rows were discarded. Approximately 270 kg of conditioned breeder seed was produced. Multiplication and distribution of all other pedigreed seed classes will be handled by Canterra Seeds, 1475 Chevrier Boulevard, Winnipeg, Manitoba, Canada ( www.canterra.com). AAC Cameron is a midge resistant variety and to maintain the effectiveness of the Sm1 gene against wheat orange blossom midge, the certified seed will include Carberry (DePauw et al. 2011) as a 10% interspersed susceptible refuge.

Contributions

JBT designed the initial cross. SLF and performed the breeding work. SK analysed the registration trials 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.