A few weeks ago we covered a topic that is familiar to many of you, selection of corn hybrids. This week we would like to dive into a similar topic, selecting soybean varieties. While this is fairly instinctual for corn hybrids, this can be a little more challenging when selecting soybean varieties. Many producers wonder, what is the best maturity? What defensive packages do I need? What type of herbicide resistances should I select? This blog post will hit on some priorities for selecting the right varieties.
The number one priority for selecting soybean varieties is yield potential. The same as corn, selecting a variety with high yield potential is essential. We cannot expect to achieve high yields from a variety with inferior genetics without the ability to perform at a high level. Select a high yielding variety to set yourself up for optimal production. Check multiple test plots, across multiple locations to get the best idea of the performance of the variety across multiple locations and environments. Among the high yielding varieties, the genetic potential is there: many of these varieties can yield well over 100 bushels per acre, and some have been recorded over 160 bushels per acre.
The second most important factor when selecting a variety is maturity. Just a refresher on how soybean maturity works. Soybean maturity is day length sensitive. Flowering or reproductive stages are triggered by the length of night or amount of darkness received. As days begin to shorten, this will trigger the plant to move from vegetative stages to reproductive. There are ten maturity groups in North America ranging from 000-VIII, with 000 as the earliest varieties and VIII as the latest varieties. In Kansas, the ideal groups are groups III-IV. This range is ideally adapted to provide the highest amount of vegetative growth but still allow for a full reproductive period and allow plants to reach maturity before the first frost. Within each maturity group, a relative maturity is given. For example, in group III, relative maturities of 3.1-3.9 are given to denote the difference in flowering days among a single group. It is important to note that the differences in maturities within a group, or within groups that are near each other will be reduced with later planting. A larger difference in days will be noticeable when planted in late April and early May. However, when these same varieties are planted in June or even as double crop in July, their flowering will occur much closer together.
Because soybeans can be selected to mature at different times, it is wise to select multiple varieties that mature at different rates, while still staying in the confines of the adapted maturity groups. For our range, you could select a low 3, mid to high 3 and a low 4 maturity to spread out the maturity dates as much as possible. This will help spread the risk as soybeans mature. Not only will this help create a timely harvest by allowing for harvest of each variety in succession, but also reduces the risk that all your soybeans will be susceptible to a specific weather event or pest pressure that could compromise yield during the growing season. It is often touted that longer maturity soybeans will be higher yielding. A lot of studies go both ways on this. Some show that longer maturing varieties will put an extra couple bushels on shorter maturities. Others show that this phenomenon is not consistent, and that shorter maturities have the same amount of yield potential as longer maturing varieties. The best way to look into this factor is just do some testing yourself. Set up some strip trials over several years to compare how various maturities and trait packages compare.
Another major factor to consider is disease and weed resistance. While we may often use fungicides and pesticides for control, however, using genetics for control may provide some costs savings, a level of backup control, and help your bottom line. A prior knowledge of the field weed pressures is useful. Keep in mind what weeds were of particular issue the last time the field was in soybeans, or even what weeds were an issue in corn. Varieties with different herbicide traits can be used to target specific weed pressures. With weeds that may be more difficult to kill, it would be wise to use a variety that has the Xtend trait in addition to the Roundup Ready traits. In the interest of mixing up traits to prevent against resistance, you may also consider Liberty Link. Keep in mind some varieties are intolerant to sulfentrazone, saflufenacil and metribuzin, while some are designed to tolerate these herbicides.
Many soybeans do have some level of disease resistance. Resistances generally range from 3-7 for issues like Frogeye, Cercospora, or Charcoal Rot. These diseases are variable from year to year, and development of disease is dependent on environmental conditions. These can be harder to plan for. Other diseases and conditions like Iron Deficiency Chlorosis, Sudden Death Syndrome, and Soybean Cyst Nematode are in a known spot from year to year. If you have an issue with them one year, it is virtually guaranteed you will have an issue with them in the future. The impact may vary, but you will see some effect from year to year. These issues are easier to plan for each year. If you know you have one of these issues, make sure you select a variety with a high level of resistance. For example, if you have high levels of SDS, select a variety like P38T20X or P38A98X which both have resistance levels of 7 out of 10.
Other Agronomic Traits to plan for include shatter score, standability, canopy width, and emergence. While many of these traits have been bred into all varieties, some still show stronger scores for standability and shatter. In general, Pioneer will not advance variety genetics that have a score lower than 6 for standability or 7 for shatter. Overall, these factors are less of a determining factor than yield potential or maturity.
Finally, seed cost should be a determining factor when selecting soybean varieties. If the relative seed cost is not going to cover the difference in yield potential, maybe take another look at variety selection. Remember, seed quality is important. If beans seem *too* cheap, that is probably for a reason.
Head over to our website to check out our 2017-2018 Soybean Test plot summaries. Results are split into 3 yield categories, high, average, and low. These include a total of 71 plots, and 633 observations. We hope that these summaries will help you pick out a top yielding variety. We’ve even categorized them by highest yielding, most consistent yielding, and most test plot wins to help you out in the decision making process. We hope these summaries can be used in conjunction with what you’ve been experiencing on your own farm.
As always, if you have any questions, both on how to pick out soybean varieties, or some of the specifics of our lineup, talk with a member of the Pederson Seed Team. We’d be happy to answer any question you may have. Interested in figuring out some maturity differences on your own farm, with your own fields and varieties? Let Rachel know and we can help set up a trial to help test for any differences in performance.