Winter malting barley breeding program

Winter malting barley
Ohio is an ideal region for producing high yields and superior quality malt from winter malting barley varieties. Cool temperatures and non-limiting soil moisture during seedling establishment and grain-fill, as well as an extended growing season are among the environmental conditions favoring high quality grain from winter barley production. In comparison, spring barleys have a much shorter growing season. Their growing season also starts and ends with highly unfavorable environmental conditions – excessively wet soils at ideal planting dates that can significantly delay planting – and excessively high temperatures during grain-fill that can drive up protein levels. The net result is low yields of grain that is unsuitable for malting and brewing. In our region winter barley is the far better choice. It also makes possible additional economic returns per acre per year because barley can be double cropped – soybean can be planted immediately following harvest of winter barley, whereas winter wheat is harvested too late to double crop. More importantly, malting barley is a high value crop that fetches a premium over feed barley and wheat. Collectively, these reasons also incentivize its use as a winter cover crop in rotation cycles – an essential but neglected issue in proper long-term land and watershed management practices.

However the environment poses a number of challenges that must be overcome. First and foremost is winter survival. Barley varieties that are to be grown commercially in the region must be winter-hardy enough to survive all but the most extreme winters that might occur during a 10–20-year interval. Climate change and less predictable winter weather patterns make assessing winter-hardiness more complex. Winter hardiness is discussed in depth in a recent review by Stockinger, 2021. Second is disease resistance. In the U.S. and North America in general, barley cultivated for malting purposes is produced primarily in semi-arid western regions where disease pressure is far less than in the humid interior central and eastern U.S. regions. Many diseases are favored by a wet environment, and some, including head scab, can render the grain crop unsuitable for any use. Third is pre-harvest sprouting, the phenomenon in which the seed germinates while still attached to the rachis (spike) prior to harvest, which occurs in wetter climate regions like the eastern U.S. Pre-harvest spouting can occur during extended periods of cool or rainy weather that preclude the ability to harvest the grain following its maturation. Barley that has undergone pre-harvest sprouting is unusable for malting because malting requires the active germination process.

Barley currently cultivated in North America for malting is almost all spring barley. Thus, for about 100 years North American barley breeders have focused on breeding for malting quality in spring types intended for cultivation in regions where environmental challenges and disease pressure are far less than or very different from those occurring in regions like ours. Moreover, these breeding efforts have focused primarily on developing varieties for adjunct brewing, not all-malt brewing. Our lab is the single dedicated winter malting barley breeding program in the region.

The Stockinger winter malting barley breeding program uses genetics and breeding to give farmers the best varieties with quality parameters for all-malt brewing and adjunct brewing. Winter hardiness will address climate change and disease resistance will enable a sellable crop. By using the tools of modern genetics that enable us to genetically-fingerprint our lines, and by linking those genetic fingerprints with important traits, we will be able to predict qualities of future lines before they are put into the field.

A snapshot of highlights from the program is shown below. Following the table is an in-depth narrative that discusses our work.

Timeline Highlights
2008–09 1st set of malting lines field tested – six-row lines from Pat Hayes at Oregon State University and UK two-row line 'Pipkin'
Two-row winter-hardy Missouri barleys (MO B) revived from USDA collection
2009–10 1st crosses: winter-hardy MO B lines × elite malting
Goal:
Develop new varieties adapted to Ohio and the neighboring Great Lake and Midwest state regions that meet quality parameters sought for all-malt brewing, in addition to varieties sought for adjunct brewing
2011–12 Trials with 'Puffin' and other UK malting lines initiated
2013–14 True test winter: Subsets of Ohio selections and MO barley lines exhibit 100% survival
'Puffin' exhibits 80% survival
'Charles' and 'Endeavor' exhibit 5–10% survival
2014–15 Commercial production of 'Puffin' at Ohio Foundation Seeds, Inc.
1st Winter Malting Barley Trial (WMBT) in Wooster
1st Eastern Spring Barley Nursery (ESBN) in Wooster
American Malting Barley Association (AMBA) supports Stockinger winter-hardy malting barley breeding program
2016 'Puffin' released in U.S.
2017–18 OSU Extension publishes Management of Ohio Winter Malting Barley
2018 'Puffin' attains AMBA malting barley variety recommendation
2018–19 15,000 new lines (doubled haploid and recombinant inbred) evaluated in Wooster
Genotyping and trait association studies initiated
2019–20 30 promising selections trialed across Ohio
2020–21 200 promising selections trialed in Wooster
Winter barley scab nursery in Wooster, supported by U.S. Wheat and Barley Scab Initiative
2021–22 70 promising selections trialed across Ohio
45 all-malt and adjunct brewing candidates enter production pipeline
2022–23 Pre-harvest sprouting – an entirely new research area


Identifying and developing winter-hardy barley adapted to Ohio and the neighboring Great Lake and Midwest state regions
The Stockinger winter malting barley program started by screening historical commercially-important winter malting barley varieties as well as sets of experimental lines. We tested promising lines across Ohio at four experiment station sites. These efforts identified the cultivar 'Puffin'. Yields were typically higher than varieties developed in earlier Ohio barley breeding programs, lodging-resistance was superior, and malting quality very good, particularly for all-malt brewing. 'Puffin' also exhibited far greater winter survival following the test winter of 2013–14 than 'Charles' and 'Endeavor', two North American winter varieties recommended by the American Malting Barley Association. In 2018 the OSU Extension published a guide for the Management of Ohio Winter Malting Barley, which is based largely on 'Puffin'. This guide pulls together the expertise of many persons at OSU and the greater barley community.

'Puffin' was developed by the Miln Marsters Group, Kings Lynn, Norfolk, in the United Kingdom. It has the pedigree ['Athos' × 'Maris Otter'] × 'Igri', and thus is a descendant of 'Maris Otter'. 'Puffin' was a commercially-cultivated variety in the UK from 1989 through 1997, and in France until about 2009. Miln Marsters no longer exists, but through a series of mergers and acquisitions was eventually absorbed into the Limagrain Group. After we had generated five years of malting quality and performance data on 'Puffin', the company Origin Malt came onto the scene, became interested in 'Puffin', and entered into an agreement with Limagrain to grow it commercially.

Additional varieties comprising the Winter Malting Barley Trial (WMBT) were trialed across Ohio in 2015–16 and 2016–17. The yield and malting quality data on a subset of the tested varieties that are commercially available, are provided in the clickable link. The WMBT is a collaborative project among U.S. barley researchers whose aim is to identify winter barley lines that meet malt industry standards. It is coordinated by the lab of Dr. Kevin Smith at the University of Minnesota (https://smithlab.cfans.umn.edu/winter-malting-barley-trial).

Early in the program we embarked on developing new varieties adapted specifically to our region. Our goal is to develop varieties that meet quality parameters sought for all-malt brewing, in addition to varieties used for adjunct brewing. Varieties used in these two systems can have very different profiles because adjunct brewing utilizes starch sources other than malted barley, and typically these sources are devoid of nutrients required by yeast for proper fermentation. As a consequence, the barley varieties used for adjunct brewing possess an excess of enzymatic strength and protein over that ideal for all-malt brewing. Additional detailed information on quality parameters can be found on the American Malting Barley Association website (https://ambainc.org/) under Publications, Guidelines for Malting Barley Breeders.

In 2009 and 2010 the first crosses were made between lines possessing superior malting quality but having inferior winter-hardiness, and lines possessing superior winter-hardiness but having inferior malting quality. We are now (2022) identifying recombinant offspring possessing the desired combination of winter-hardiness and malting quality, several of which derive from crosses to 'Puffin'. Many are in the production pipeline for commercial release and could be trialed by interested parties for pilot malting and brewing as early as the 2022–23 season. Preliminary malting quality data for these lines is available and can be accessed by the clickable links in the table below. The data are preliminary since not all lines have been tested at multiple locations over multiple years.

There are four files, and their titles are intended to be self-explanatory. For comparative purposes, the malting quality data for standard commercially available varieties grown in parallel, is also provided.

Stockinger malting barley lines that could soon be available on tap at your local pub:
Elite lines in production plots for pilot malting and brewing 2022
Promising 'Puffin' progeny in the production pipeline
All-malt elite lines entering the production pipeline 2021–22
All-malt elite lines expected to enter the production pipeline 2022–23


These selections are presented because most exhibit ideal protein and free amino nitrogen (FAN) levels for all malt brewing. The malting quality data was generated by the USDA Cereal Crops Research Unit (CCRU) in Madison WI, which uses steeping, germination, and kiln cycle schedules designed to produce adjunct lager type malts. Thus, altering those schedules and parameters may bring other quality parameters much closer to desired ideal levels. Additional highly-promising lines are also being trialed. 

Related breeding objectives
The greatest threat to barley is probably the disease Fusarium Head Blight. Also known as head scab, it is caused by the fungal organism Fusarium graminarum and can render the grain unfit for consumption because it produces a multitude of toxins having various levels of toxicity to human and animal digestive systems. The disease has always been a problem, but its incidence has been tremendously exacerbated because of changes in maize cultivation practices and climate change. It continues to intrude into previously pristine areas as it follows the expansion of cultivated maize acreages. Thus, it is a complex agro-economic problem. The best means to combat the disease is through the use of resistant varieties and appropriate management practices.

To identify lines possessing resistance to Fusarium graminarum we established a scab nursery for winter barley in 2020-21. The idea is to put every line through a gauntlet of disease pressure so that only the most resistant varieties emerge. We are assessing disease incidence of each line and determining the grain toxin levels, including that of deoxynivalenol (DON), which has long been used as a key indicator of fungal contamination levels in grain. Currently, we are testing ~260 different barley lines. We plan to continue trialing lines in future scab nurseries in order to provide farmers with the best resistant lines. This work is supported by the U.S. Wheat and Barley Scab Initiative (https://scabusa.org/).

Pre-harvest sprouting is an entirely new research area for us. Nonetheless in this regard we are fortunate to have an excellent research program investigating pre-harvest sprouting in wheat in the USDA Soft Wheat Quality Laboratory in Wooster. It is anticipated that many of the mechanisms and genes are likely conserved between wheat and barley. A recent review on pre-harvest sprouting can be found in Patwa and Penning 2020.

Future directions
We have built a foundation of exceptional breeding germplasm by creating populations that combine winter-hardiness with malting quality, alongside a host of other highly desirable agronomic traits. Lines used to build this foundation all came from outside programs. As we move into the next phase of the breeding program our best lines are being crossed with each other to raise the bar higher and provide farmers with the best lines possible – higher yielding in terms of bushels per acre, and higher yielding in terms of extract per pound of malt. We now have offspring of 'Puffin' that exhibit tremendous improvements over 'Puffin' in our region. We are also advancing promising selections derived from crosses to 'Pipkin', the very first two-row line tested in Ohio. 'Pipkin' like 'Puffin' is a descendant of 'Maris Otter’ but is also highly notable for being ideal for malt whiskey production, as it is an epiheterodendrin non-producer (non-glycosidic nitrile) (Bringhurst, 2015; Stockinger, 2011, 2021). Many of our breeding lines also possess novel mechanisms for carbohydrate metabolism and total fermentable sugars (Henson et al., 2021), which is anticipated to give greater flexibility for brewers and distillers. We are also genetically-fingerprinting our lines to identify regions of the genome responsible for conferring traits of interest – for the purposes of developing a better mechanistic understanding of these traits and to expedite the breeding process, so that we can predict trait qualities of future lines before they are put into the field.

References
Bringhurst, T.A. (2015). 125th Anniversary Review: Barley research in relation to Scotch whisky production: a journey to new frontiers. Journal of the Institute of Brewing 121, 1-18. https://doi.org/10.1002/jib.192

Henson, C.A., Duke, S.H., and Vinje, M.A. (2021). Comparison of Wort Osmolyte Concentration and Malt Extract to Wort Sugars from Malting Barley Breeding Lines. Journal of the American Society of Brewing Chemists, 10. https://doi.org/10.1080/03610470.2021.1914986

Patwa N, Penning BW (2020) Environmental Impact on Cereal Crop Grain Damage from Pre-harvest Sprouting and Late Maturity Alpha-Amylase. In: Roychowdhury R, Choudhury S, Hasanuzzaman M, Srivastava S (eds) Sustainable Agriculture in the Era of Climate Change. Springer International Publishing, Cham, pp 23-41. doi:10.1007/978-3-030-45669-6_2. https://link.springer.com/chapter/10.1007%2F978-3-030-45669-6_2

Stockinger, E.J. (2011). Pipkin. In The Oxford Companion to Beer, G. Oliver, ed. (New York: Oxford University Press), p. 656.

Stockinger, E.J. (2021). The breeding of winter-hardy malting barley. Plants (Basel) 10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8309344/