Over the past couple of years many of you have anxiously watched the progress of the new public soybean variety Bolivar, the first to come out of the USDA breeding program in several years.
Bolivar is a tall-growing variety. It has an excellent disease package and will branch extremely well. It is well-adapted for heavy clay, and it is a more growthy variety than Hutcheson, both in height and branching.
Last spring Mississippi State Foundation Seed Stocks had about 3,000 units available for seed production. Approximately 20 producers in both Mississippi and Arkansas grew Bolivar for seed increase.
Throughout the growing season I made an effort to see as many locations as I could. Except for some variations in management strategies, Bolivar looked extremely good. However, at harvest we began to notice a condition known as bleeding hilum that concerned some folks.
Bleeding hilum, a condition where the eye of the soybean appears to bleed out into the seed coat, is most often associated with soybean mosaic virus (SMV). Although other things can cause bleeding hilum, it caused concern because SMV is seed-transmitted. When we evaluated seed from most seed growers, we found that the percentage of bleeding ranged from 0 to 35 percent visible symptoms.
Even though bleeding was observed on the seed, none of the visible symptoms that are often associated with SMV were found in the field.
Since Bolivar is the first public soybean variety in Mississippi in several years, we wanted to be cautious of any potential problems. Seed from several lots were sent to AGDIA for a virus screen. All came back negative. Seed from each grower we contacted (approximately 15) were sent to Sue Tolin at VPI for further analysis. She is a recognized authority on viruses and has been collecting viruses in recent years to determine what is present in the United States and what resistant sources are available.
Bolivar was rated as resistant to SMV, but due to the high degree of bleeding, we thought Dr. Tolin's input was needed. In initial conversations she told us a new strain of SMV that has been identified could affect varieties currently resistant. Bolivar is resistant just like Hutcheson, but she wanted to see if a strain she had found on Hutcheson was also affecting Bolivar.
Testing has been completed on about half the lots, but given the time of year, we think we can wait no longer. Dr. Tolin will continue testing and keep us posted. For now we want to explain what has taken place and what you should consider for this upcoming growing season.
We know that Bolivar has no more of a problem than Hutcheson. In the 10 to 15 years we have been growing Hutcheson we have never seen or experienced a problem. One major difference that separates Hutcheson and Bolivar is that Hutcheson has a buff-colored hilum — it is not black like Bolivar. Therefore, this may have been occurring on Hutcheson but with no visible seed symptoms. Regardless, no field problems have ever been reported.
The question we still have and cannot answer until Dr. Tolin finishes testing is why is there variability in bleeding hilum between different growers since the seed were all only one generation from foundation seed.
Were we too cautious? Probably. But because it is the first public variety released in a while, we wanted it to have good success. Public varieties have a place and many different varietal options will surface for your use in the near future.
In reality, this variety has been tested and looked at more than most other varieties that are available.
Bolivar is a good-yielding variety with excellent potential in Mississippi. Bolivar is similar to Hutcheson in resistance to SMV, and there has not been a problem thus far. Yes, we will learn more in the next few weeks.
If you are interested in a good high-yielding conventional variety for clay soil, consider Bolivar. Is it problem-free? No, but unless we see more evidence of a problem, it is worthy of planting.
We will be looking in the fields this summer and will keep you up to date, but rest assured this is a variety that has jumped more hoops than many of its private counterparts.
If you have any additional questions or comments regarding this or others during the year, please do not hesitate to let us hear from you.
Alan Blaine is an Extension soybean specialist with Mississippi State University.