Soybean Seed Quality - May 22, 2009
Dr. Rick Cartwright - Extension Plant Pathologist
[Title Slide – Soybean Quality, Dr. Rick Cartwright, Extension Plant Pathologist, Number 1 – May 22, 2009, Your Arkansas Soybean Podcast, University of Arkansas Division of Agriculture, Arkansas Soybean Promotion Board]
[Dr. Cartwright] Hi, I’m Rick Cartwright, Plant Pathologist with the University of Arkansas Division of Agriculture, and today we are going to talk about soybean seed quality.
[Slide – Seed quality is important. Arkansas climate and geology is different than other production regions; changes from year to year; critical for establishing a uniform stand] Soybean seed quality has become an increasing issue in Arkansas due to repeated stand failures in recent years, and the increased expense of soybean seed. [Slide - Soybean Quality Project. Started April 2008; Funded by Arkansas Soybean Promotion Board; Research and education goals] In April 2008, the Arkansas Soybean Promotion Board funded a research and extension project through the Division, [picture of a publication Understanding Soybean Seed Quality] focused on understanding the causes of seed quality problems in Arkansas and educating growers and the industry on these issues.
[Slide – Rating Seed Quality. 1. Standard Germination Test; 2. Accelerated Aging Test – test seed vigor] Seed quality is complex but there are two basic tests used to rate it. [Slide – Standard Germination Test. Tests for a seed’s ability to produce a normal seedling under optimum conditions.] The standard germination test determines the percentage of seed that produce a normal seedling under optimum temperature and moisture conditions. [Slide – Germ Values. 80% and above – good quality; Germ value is required on all seed sold.] Seed with no less than an 80% germ, at testing time, is considered of good quality. [Picture of germinated seeds – standard germ comparison poor germ versus good germ] Germination test results are required to be provided, generally on a bag tag or invoice, on all seed sold in the state.
[Slide – Accelerated Aging Test, Tests for a seed’s ability to produce a normal seedling after being “aged” at high temperature and moisture for three days.] The accelerated aging test determines the percentage of seed that produce a normal seedling after being “aged” at high temperature and moisture. [Picture showing Accelerated Aging Comparison of poor A A versus good A A] The AA test estimates seed “vigor,” the ability of seed to emerge in the field [Picture showing soybean plant poor emergence due to poor seed vigor.] under varying conditions. Vigor is very important, especially in Arkansas, where field conditions can be rough at planting. [Slide – A A values. Estimated seed vigor; 65% and above = good vigor] Seed with an AA value of 65% or greater is considered to have good vigor.
[Slide – Vigor A A test. Not required on seed sold, but ask seed dealers for the A A test results; Vigor changes over time; Re-test seed if planting in June or July] Vigor test results are not required to be provided on seed sold in the United States, however most seed dealers will provide the test results for any seed lot they sell, if requested. [Picture of farm equipment] Since vigor changes over time, consider having your planting seed re-tested if you are planting in June or July, when planting conditions may be harsh. [Picture of a soybean field with emerging plants]
[Slide – Good quality seed indicates 80% minimum germ plus 65% minimum accelerated aging] A good rule of thumb is a minimum of 80% germ combined with a minimum of 65% accelerated aging are indicators of quality seed.
[Picture of soybean seed] The 2009 Soybean Seed Quality Survey is underway, [Picture of seed bags in a warehouse] and we need your help collecting samples. Last year was the first year for this statewide planting seed survey implemented [Picture of an open bag of seed] to determine the germ and vigor of soybean seed in Arkansas. [Slide – What we learned from 2008 seed survey – germ value didn't change much over four month survey period and A A values (vigor) declined over four month period.] Basically, we found that germ did not change much over the almost four months of the survey, but the accelerated aging test values – or vigor – declined quite a bit. [Slide – 2009 Seed Quality Survey – 2nd year – same format as 2008, Sample collection period = May 1 through July 31, 2009, Three pound sample – about 6 inches of seed or height of a coke can, County agent will be collecting samples] From May 1 to the end of July, county extension agents will be collecting 3 pound seed samples [Picture of a coke can next to a sample bag of seed] from cooperating growers as well as field, planting and resulting stand information. [Picture of a form] Please help these agents when they contact you.
[Picture of seed bags on a pallet in a shed] Among the many factors that affect seed quality, storage and handling conditions are considered very important. [Slide – Seed Storage Trials – two soybean varieties, three storage locations in state, samples taken every two weeks, Samples taken very two weeks, Watch Dog data logger monitors temperature and humidity] This year, project researchers are investigating this by monitoring soybean seed stored under different conditions [Picture of a Watch Dog data logger] at three regional seed companies in the state this year.
[Slide – Remember, seed is an investment, understand what seed quality is and why it is important, ask questions] The bottom line is, seed is the first and foremost investment in your crop. Make sure your investment pays off, and comes up. Know the quality of the seed you are buying, and if you have questions … just ask.
Your Arkansas soybean podcast is a production of the University of Arkansas Division of Agriculture and was funded in part by the Arkansas Soybean Promotion Board. For more information on soybean farming in Arkansas, contact your local county Extension office.