Introduction

The northern regions of the western Canadian Prairies, or Parkland Region, is the eco-climatic zone which stretches from north-eastern British Columbia throughout northern Alberta, northern Saskatchewan, and northern Manitoba. The northern prairies extend north of 51°N latitude in Manitoba, north of 53°N in Saskatchewan, and north of 55°N in Alberta. The northern prairies are also characterized by prevalence of gray to dark gray soil and lower growing degree days (GDD; Porter and Gawith 1999) compared with the brown to black soil type and higher GDD in the southern prairies (DePauw et al. 2011a). The GDD at southern prairie locations such as Brandon (Manitoba) and high (Saskatchewan) are 1456 and 1476 units, whereas the northern prairie locations such as High Level (Alberta) and Grand Prairie (Alberta) have lower GDD values of 1086 and 1208 units, respectively. The mean temperature from April to August is approximately 2 °C lower in northern prairies compared with the southern prairies (DePauw et al. 2011a). The killing frost-free days, calculated as the number of days between the last day prior to 1 July and the first day after 1 July with minimum temperature less than 2.2 °C (Hay and Porter 2006), is generally lower in northern prairies compared with the southern prairies (DePauw et al. 2011a). The northern prairies are best suited to wheat varieties that grow faster and yield more with fewer GDD, fewer killing frost-free days, and lower mean temperature during the growing season. Thus, a focused and targeted breeding effort is required to breed wheat varieties truly suited to the northern prairies. The majority of the wheat acreage in the Parkland Region is in northern Alberta. This region is characterized by an extremely short growing season, long day length, and short cool nights. Disease pressure in the Parkland Region is typically lower than in the Western and Central Prairies, especially for Fusarium head blight (FHB) (Fusarium graminearum Schwabe). Stripe rust (Puccinia striiformis Westend.) is an emerging threat, and seasonally, orange wheat blossom midge (Sitodiplosis mosellana Géhin) pressure can be very high. With recent changes in Canada Western Red Spring (CWRS) gluten strength targets, there is a lot of opportunity for new CWRS varieties to capture space in growers’ fields in the Parkland Region with early-maturing lines that have strong agronomic qualities and good disease resistance. AAC Redstar hard red spring wheat was developed at the Brandon Research and Development Centre (BRDC), Agriculture and Agri-Food Canada (AAFC) in Brandon, MB, Canada. Tested as PT488 and 09B12-FJ2D, AAC Redstar was granted registration No. 8923 from the Variety Registration Office, Plant Production Division, Canadian Food Inspection Agency on 7 Feb. 2020. Plant Breeders’ Rights application No. 19-829 was accepted for filing on 1 May 2019.

Breeding Methods and Pedigree

AAC Redstar is derived from the 2009 cross AAC Redwater/CDC Plentiful. The female parent, AAC Redwater (Zi et al. 2017) was derived from the cross Harvest/McKenzie//AC Intrepid (DePauw et al. 1999; Graf et al. 2003; Fox et al. 2010). The male parent, CDC Plentiful was selected from the cross BW282/CDC Go. Both parental lines, AAC Redwater and CDC Plentiful, are currently registered cultivars belonging to the CWRS market class. A detailed description of the breeding history, cultivar evaluations, and Breeder Seed development is outlined in Table 1. Briefly, 24 F₁ plants were increased in the greenhouse at the Beaverlodge Research Farm, AB, during winter 2009–2010 under the designation 09B12. Then, 12 F₂ bulk plots were grown at the Beaverlodge Research Farm in 2010. Spikes (30) were picked from each F₂ plot and planted as F_2:3 spike-hills in the 2010–2011 contra-season nursery in Palmerston North, NZ. Five spikes were selected per hill “FJ” and planted as single 1 m spike-rows in the 2011 Beaverlodge hybrid nursery; the F_3:4 row that gave rise to PT488 was designated 09B12-FJ2. F_3:4 rows were selected based on plant type, resistance to rusts and common bunt [Tilletia caries (DC.) Tul. & C. Tul.], protein concentration, flour yield, and mixograph testing. Selected rows were increased as 1 m F_3:5 single rows in Palmerston North, NZ, in winter 2011–2012 and selected for plant type and leaf rust (Puccinia triticina Erikss.) resistance. In 2012, selected F_3:6 lines were grown as yield plots in a randomized complete block design (RCBD) with 108 entries. Successful lines were based on high yield, early maturity, resistance to lodging, moderate height, acceptable end-use quality (flour yield, falling number, and mixograph), resistance to leaf, stem (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.), and stripe rust, and FHB resistance. Six heads collected from 09B12-FJ2 were grown as 1 m F_6:7 rows in the Palmerston North, NZ, 2012–2013 contra-season nursery, where the row that became PT488 was designated 09B12-FJ2D and selected to progress to the “F₈ level testing” in 2013. 09B12-FJ2D was tested within an RCBD design with 108 entries, one replication at three locations, and was evaluated in the combined leaf, stem rust, and FHB disease nursery at Brandon, MB. Selections were made on a similar basis as the F₆ generation. This line was subsequently evaluated in the 2014 “ParkA1” test as a 7 × 7 lattice with two replications at five locations and the 2015 “Parkland B” test as a 5 × 5 lattice with three replications at seven locations. 09B12-FJ2D was given the designation PT488 and evaluated over 3 yr (2016–2018) in the Parkland Wheat Cooperative registration trial. The variables measured and the operating protocols followed in the registration trial were those approved by the Prairie Recommending Committee for Wheat, Rye and Triticale ( http://pgdc.ca/committees_wrt_pd.html). The check cultivars were AC Splendor (Fox et al. 2007), Glenn (Mergoum et al. 2006), Parata (Spaner et al. 2016), Carberry (DePauw et al. 2011b), and in 2016, PT472, an unregistered line from the BRDC, AAFC. The data for the test were analyzed for individual years and combined following a mixed model design in SAS version 9.4 (SAS Institute Inc., Cary, NC, USA), with environments and replications as random effects and genotype as a fixed effect. In the registration trials, the stem rust races were TPMK, TMRT, RHTS, QTHS, RTHJ, RKQS, and MCCF (Fetch et al. 2011). The leaf rust inoculum comprised a mixture of prevalent races isolated from the western Canadian prairies as determined from yearly survey studies (McCallum et al. 2016, 2017). Resistance to races T2, T9, T10, and T39 of loose smut [Ustilago tritici (Pers.) Rostr.] (Menzies et al. 2003) and resistance to a mixture of prevalent races (L1, L16, T1, T6, T13, and T19) of common bunt (Gaudet and Puchalski 1989; Gaudet et al. 1993) were evaluated in the Parkland Wheat Cooperative registration trials. Resistance to FHB was tested using the macroconidial spore suspension (University of Manitoba, Carman, MB) or corn spawn (Morden Research and Development Centre, MB) inoculum. An equal proportion of four isolates (M1-07-2/15ADON, M3-07-2/15ADON, M7-07-1/3ADON, and M9-07-1/3ADON) of F. graminearum was also evaluated in the Parkland Wheat Cooperative registration trials. End-use quality analyses were conducted at the Grain Research Laboratory, Canadian Grain Commission using approved methods (American Association of Cereal Chemists 2000) each year on composite grain samples from all locations with no serious down-grading factors. End-use quality data from the composite samples of AAC Redstar and check cultivars for each year were used as replicates to estimate least-square means for all quality traits over the 3 yr of testing.

Table 1.

Population size and activities at each generation leading to the development of AAC Redstar hard red spring wheat.

Plant descriptive characteristics were recorded from a three-replicate trial conducted in a RCBD at the AAFC Saskatoon Research Farm in Saskatoon, SK, during 2018 and 2019. This trial included the reference cultivars AAC Redwater and CDC Plentiful. All characteristics were recorded as prescribed in the Objective Description Form of the Variety Registration Office, Canadian Food Inspection Agency.

Performance

Agronomy

Averaged over 35 site-years AAC Redstar was significantly higher yielding than the mean of the checks (P < 0.05), and averaged 11% higher than AC Splendor, 6% higher than Parata, and 4% higher than either Glenn and Carberry (Table 2). AAC Redstar had similar maturity to Parata, was 2 d earlier than Carberry, 3 d earlier than Glenn, and 1 d later than AC Splendor. AAC Redstar was shorter than all checks except Carberry and had a lower mean lodging rating than all the checks (Table 3). Test weight, kernel weight, and whole grain protein concentration were similar to Carberry.

Table 2.

Yield (kg·ha⁻¹) of AAC Redstar and check cultivars in the Parkland Wheat Cooperative registration trials (2016–2018).

Table 3.

Summary of agronomic traits of AAC Redstar and check cultivars in the Parkland Wheat Cooperative registration trials (2016–2018).

Disease

FHB index and DON accumulation of AAC Redstar were consistently equal to or lower than Carberry (Table 4). AAC Redstar was resistant to the prevalent races of stem rust and loose smut, and moderately resistant to leaf rust, stripe rust, and common bunt (Tables 5 and 6).

Table 4.

Fusarium head blight VRI^a, DON, and ISD^b for AAC Redstar and check cultivars in the Parkland Wheat Cooperative registration trials (2016–2018).

Table 5.

Rust disease severities and ratings of AAC Redstar and check cultivars in the Parkland Wheat Cooperative registration trials (2016–2018).

Table 6.

Bunt, smut, and leaf spot of AAC Redstar and check cultivars in the Parkland Wheat Cooperative registration trials (2016–2018).

End-use quality

AC Redstar was deemed eligible for all grades of the CWRS wheat class. The results of end-use quality testing are summarized in Tables 7 and 8. AAC Redstar had a consistently high falling number and clean wheat flour yield. Grain protein content was within the range of the checks, except in 2018 when it was slightly lower. Dough strength as determined by extensograph was consistently higher than Carberry in all 3 yr of testing (Table 8).

Table 7.

Wheat and flour analytical data for AAC Redstar and check cultivars from the Parkland Wheat Cooperative registration trials (2016–2018).

Table 8.

Dough properties and baking qualities for AAC Redstar and check cultivars from the Parkland Wheat Cooperative registration trials (2016–2018).

Maintenance and Distribution of Pedigreed Seed

Breeder Seed of AAC Redstar was produced using 250 random spikes from a rogued seed increase plot grown at Saskatoon, SK, in 2016. These spikes were grown as an isolated group of 1 m single spike-rows in 2017 in Brandon, MB; 23 lines were rejected for lack of uniformity. In 2018, 227 pre-breeder seed rows were grown at the Seed Increase Unit, Indian Head, SK; each 15 m length row was rogued for uniformity, and seven rows were discarded. The remaining rows were inspected and harvested in bulk, producing 265 kg of Breeder Seed. Multiplication; distribution of all other pedigreed seed classes will be handled by SeCan, 400-300 Terry Fox Dr., Kanata, ON K2K 0E3, Canada ( https://www.secan.com/).