AAC Reid is a white-hulled, covered spring oat (Avena sativa L.) cultivar developed by the Ottawa Research and Development Center, Agriculture and Agri-Food Canada. It is highly resistant to crown rust (Puccinia coronata f. sp. avenae) and demonstrated superior levels of grain yield, test weight, kernel weight, lodging resistance, β-glucan, and groat content in the crown rust-prone regions (Areas 2 and 3) of Ontario from 2016 to 2021.
Introduction
AAC Reid, tested under the code OA1444-4, is a white-hulled, covered spring oat (Avena sativa L.) cultivar developed by the Ottawa Research and Development Center (ORDC), Agriculture and Agri-Food Canada (AAFC). It was supported for full registration by the Ontario Cereal Crops Committee (OCCC) in January 2019 and granted registration by Canadian Food Inspection Agency (CFIA) in November 2020, with the registration number 9126. This article documents its breeding history, performance, and morphological characteristics.
Breeding History
AAC Reid was developed from the cross 10W06 (SA04213/OA1271-3), made in November 2010 at ORDC. SA04213, registered as Hidalgo, was a University of Saskatchewan line that was tested and registered in eastern Canada by Phytogene Inc.; it has high groat content and β-glucan content. OA1271-3 was an ORDC line, which demonstrated high yield, high β-glucan, and superior resistance to crown rust and other leaf diseases in the ORDC Registration trials during 2017–2019. However, this line was low in groat content and showed poor grain setting under some winter time greenhouse conditions. It was supported for registration by OCCC in 2010 but subsequent registration was not pursued. The cross 10W06 was increased to F3 in a greenhouse at Ottawa. A total of 164 F4 individuals were grown in the hill plot nursery in 2012 at Ottawa, and 75 were visually selected for plant and grain characteristics. Selected lines were grown in four-row plots in the 2013 observation nursery, and six lines were visually selected for canopy, plant, and grain characteristics. Selected lines were advanced to the 2014 Home Test, which was conducted at four locations (Ottawa ON, New Liskeard ON, Normandin QC, and Harrington PE) with two replicates. All six lines, designated as OA1444-1 to OA14444-6, respectively, were advanced to the 2015 Preliminary/ENCORE Test, which were conducted at 10 locations (Brandon MB, Fargo ND, Lacombe AB, New Liskeard ON, Normandin QC, Ottawa ON, Palmerston ON, Harrington PE, Princeville QC, and Saskatoon SK), with two or three replicates depending on the location. OA1444-2, OA1444-4, and OA1444-5 were advanced to the ORDC Registration Test in 2016, which was conducted at 10 locations across Canada (see Table 1 for the list of locations). OA1444-4 and OA1444-5 were further tested in 2017 and 2018. OA1444-4 demonstrated superior yield, grain and milling quality, and resistance to crown rust, and was supported for registration by the OCCC in January 2019. It was granted registration as AAC Reid by the Canadian Food Inspection Agency (CFIA) in November 2020, with the registration number 9126.
Table 1.
Grain yield from the 2016–2018 ORDC Registration trials.

Yield performance
The grain yield performance of AAC Reid in the 2016–2018 ORDC Registration trials is summarized by mega-environments (MEs) in Table 1, with AAC Bullet (Yan et al. 2017) and AAC Nicolas (Yan et al. 2016) as check cultivars. The oat growing regions in Canada consist of three MEs (Yan et al. 2021). ME1 consists of Areas 2 and 3 of Ontario, characterized by relatively low latitude and heavy crown rust pressures. ME2 consists of northern Ontario, Quebec, and the Maritimes, and ME3 consists of the Canadian prairies. Currently, AAC Bullet is the dominant oat cultivar in ME1 and AAC Nicolas is one of the most popular cultivars in ME2.
When viewed across all trials covering all three MEs, AAC Reid yielded higher than AAC Bullet but not higher than AAC Nicolas; however, it yielded 14% higher than AAC Nicolas and 20% higher than AAC Bullet in ME1 (Table 1). AAC Reid yielded lower than AAC Nicolas in other regions. Thus, it is an oat cultivar specifically adapted to ME1.
AAC Reid continued to perform well in the OCCC performance trials after registration. From 2019 to 2021, it yielded 25.6% higher than AAC Bullet in Area 2 of Ontario when no fungicide was applied; however, it yielded only 3.5% higher when a fungicide was applied, because the yield of AAC Bullet was significantly increased by fungicide application (Table 2). This suggests that the yield advantage of AAC Reid over AAC Bullet was mainly due to its superior resistance to crown rust and possibly other fungal diseases. Two sprays of a fungicide is a common practice for a profitable oat production using AAC Bullet in Area 2 of Ontario (Martin Quentin, personal communication, Crebit Seeds, 2018)
Table 2.
Yield index (% of trial mean) of AAC Reid and AAC Bullet with and without fungicide application in Area 2 of Ontario.

Agronomic traits and crown rust resistance
AAC Reid had similar days to maturity to that of AAC Bullet and AAC Nicolas. It was taller than both checks but was not more susceptible to lodging, which may be related to its superior resistance to crown rust (Table 3). Between the two parents of AAC Reid, SA04213 is highly susceptible to crown rust. Thus, the crown rust resistance of AAC Reid must be from OA1271-3. The parentage of OA1271-3 was TAMO-312/07085-15-5-3//Coker 234/07085-15-5-3. TAMO-312 was known to carry Pc59 and Coker 234 was known to carry Pc61 (Simons et al. 1978). In addition, the line 07085-15-5-3 has a parent carrying Pc62. Thus, OA1271-3 and, therefore, AAC Reid may carry one or more of the crown rust resistance genes Pc59, Pc61, and Pc62. Menzies et al. (2019) reported that Pc59 was highly effective and Pc62 moderately effective against crown rust in eastern Canada as of 2015. Brouwer (1983) reported Pc59 resistance being conditioned by three unlinked genes.
Table 3.
Data of agronomic traits from the 2016 to 2018 ORDC Registration trials.

Grain and compositional quality
Across the 2016–2018 ORDC Registration Trials, AAC Reid showed slightly lower test weight and kernel weight than AAC Bullet (Table 4); however, it had much higher test weight and kernel weight than AAC Bullet under severe crown rust pressures (data not presented). Importantly, AAC Reid showed significantly higher levels of β-glucan, groat, and protein than both check cultivars (Table 4), making it a superior milling oat. AAC Reid had higher oil content than the check cultivars (Table 4), but the oil level is within the limit for milling oat (<8.5%).
Table 4.
Grain and compositional quality from the 2016 to 2018 ORDC Registration trials.

Morphological characteristics
Coleoptile color: green
Seedling growth habit: semi-erect
Leaf characteristics
Leaf blade pubescence: absent to very sparse
Leaf sheath pubescence: absent to very sparse
Leaf color: medium green
Leaf margin pubescence: absent to very sparse
Frequency of plants with curved flag leaves: medium
Flag leaf length: long
Flag leaf width: medium to narrow
Panicle characteristics
Panicle orientation of branches: equilateral (symmetrical)
Panicle density: medium
Panicle attitude of branch position: erect
Side branch angle: less than 30 degrees
Rachilla characteristics
Rachilla length between primary and secondary florets: long
Rachilla pubescence: absent to very sparse
Length of grooves: absent to very short
Spikelet characteristics
Spikelet separation: fracture
Spikelet attitude: semi-nodding
Glum length: medium to long
Number of grains per spikelet: two
Acknowledgements
We thank the AAFC and the Canadian Field Crop Research Alliance (CFCRA) for funding the ORDC oat breeding program and for the technical support at the various trial locations.