12th International Symposium on Pre-Harvest Sprouting - Holly Gelech, Biovision Seed Labs

Photo credit: Thomas Lumpkin/CIMMYT.

By Holly Gelech, Biovision Seed Labs

The 12th International Symposium on Pre-Harvest Sprouting in Cereals was hosted the week of July 24th in Red Deer, Alberta and was attended by 60 participants from all regions of the globe. The 35 speakers, who originated from Australia, China, Japan, United Kingdom, Africa, Canada and many others countries, discussed their research and conclusions on the topics of sprouting and dormancy in cereal grains.

Dr. Jim Helm from AARD’s Field Crop Development Centre in Lacombe kicked off the conference with a well rounded review of Canadian plant breeding, then outlined his opinions on how plant breeding excellence will be achieved in the future. Through Dr. Helm’s 47 years of breeding experience he has forged international relationships, which has facilitated the sourcing of cereal genetics from the US, Mexico, Argentina, Ecuador, Uruguay, Syria, Kenya and Australia. Breeding objectives traditionally have been focused on productivity and end use traits, as driven by funding priorities. Tertiary characteristics such as pre-harvest sprouting and dormancy have been simply a “nice to have” component in a holistic view of varietal development. Dr. Helm stressed that going forward, sustainable and successful Canadian plant breeding requires:

• A balance between academic (biotechnology) and applied (agronomy, plant breeding) research.
• Cooperation and/or partnership between public and private breeding institutions.
• Collaboration between end-use industry and research organizations.
• Focus on economics for both the producer and end-user.

The 4 day Symposium was truly a mind numbing experience. Scientists, with stacked educational degrees and appointments, presented their topics in detail through the support of statistical analysis and quantitation. I was somewhat surprised with the question period that followed each presentation. The audience was given this opportunity to support, challenge and provide recommendations to the presenter. Not a single presentation went without discussion, and the odd case emerged where a line was drawn, with varied opinions not wavering.

Sprouting can range from perhaps undetectable to severe within Canada’s vast grain producing regions. An Australian researcher at the Symposium announced that in 2010, 50% of the wheat crop was affected by pre-harvest sprouting to various degrees. Obviously this is disheartening not only to a grain producer, but to processors. Finicky consumers do not want discolored pasta or collapsed bread loafs! The following topics, relative to sprouting, were highlighted at the Symposium.

1. Chromosome Identification: New chromosomes that impact sprouting were presented, and are now added to the growing list of loci discovered. The list has now expanded to include chromosome 1D, 2D, 3D, 4A, 5D and 6D (Australia).
2. Use of Diverse Genetic Sources: Heritage wheat populations are being evaluated for natural variation and alternative sources, such as synthetic wheat and grass species, are now being analyzed (Australia).
3. Identifying Wheat Class Triggers: Researchers are also investigating the reason why red wheat has a higher sprouting resistance than white wheat. This phenomenon is still under investigation, but it is apparent that the red pigment plays a significant role in the biosynthesis and/or uptake of essential water and oxygen for sprouting (UK & US).

Dr. Ron Depauw from AAFC’s Semi-arid Prairie Agricultural Research Centre outlined the difficulties breeders face in developing pre-harvest sprouting in cereals. Kernel sprouting in the field is not only controlled by genetics, but also by growing conditions. Dr. Depauw discussed that genetic sources to reduce pre-harvest sprouting have long be used for CWRS and CWHWS classes, but no unique gene has been identified to trigger resistance. To further complicate the breeding process, environmental conditions that promote pre-sprouting are not present in field trials consistently. Artificial rain simulators are deployed at research stations as a work around, but this limits testing to greenhouse trials. Dr. Joseph Nyachiro also spoke to the genomic-environmental cause of pre-harvest sprouting and indicated that the environment is the most significant contributor, but that the genotype will benchmark the susceptibility.

BioVision Seed Labs’ presented analytical data that compared the frequency of dormancy in the 2010 seed crop to the 2009 seed crop. The below summarizes my review of dormancy:
2010: 7% of the samples tested at BioVision demonstrated dormancy.
2009: 1% of the samples tested at BioVision demonstrated dormancy.
2010: 2.2% of the samples tested at BioVision demonstrated dormancy.
2009: Rare detection of dormancy.
2010: 5.75% of the samples tested at BioVision demonstrated dormancy.
2009: 0.5% of the samples tested at BioVision demonstrated dormancy.

Maximum Dormancy Detected in the 2010 seed crop:
Wheat: 42% of kernels were dormant
Barley and Oats: 23% of kernels were dormant

Numerous researchers presented data supporting that a cool period, also referred to as a “shock”, at 25 days post anthesis (flowering) can induce seed dormancy (UK & South Africa). It would be quite interesting to compare crop staging and temperature data from samples that BioVision tested last season and confirm that this statement holds true for Canadian wheat production. Traditional literature has proven that dormancy is an imbalance of abscisic acid and gibberellin within the kernel, which inhibits and stimulates germination respectively.

The 12th International Symposium on Pre-Harvest Sprouting in Cereals brought together an outstanding wealth of knowledge that was truly inspiring, and demonstrated the complex research conducted worldwide to understand cereal grain physiology, genetic pathways and trait expression.

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