25 Feb Selecting a Sorghum Hybrid
Selecting a Sorghum Hybrid
Hybrid and variety selection is one of the most important decisions that growers make. We often focus on yield when selecting a sorghum hybrid and face it, we should because that is what matters. However, do we ever think about how we got to the yields we measure in the field? Most of the time we address environmental challenges we might face through host-plant resistance or tolerance in the hybrids we choose.
Sugarcane aphids (SCA) are a prime example of this. When we had very few hybrids that were resistant to SCA, we focused a lot on pesticide options and learning to scout. Now that most of the hybrids on the market have some level of tolerance, scouting is all we worry about. Drought stress is a cornerstone to good grain sorghum yields a focus of most sorghum breeding programs. A couple of traits that we rely on at S&W are Stiff stalk and Staygreen. Stiff stalk is explanatory in that this brings a stiffer outer rind to the stalk allowing it to stand better when drought affects the internal stalk integrity. Staygreen helps the plant maintain green leaves under stress, which is important. When plants experience drought stress, their leaves begin to senesce or die. Now the plant has a limited ability to produce photosynthates and feed itself. Under these conditions, the plant will remobilize carbohydrates out of the stem to try and finish filling grain if we are in grainfill. This causes the stalk to become weak or susceptible to stalk rots. Now lodging can be a problem. So, you can see how a stiffer stalk and a trait that keeps the leaves green and producing photosynthates for the plant under drought stress are important. Hybrids with these two traits should have good drought tolerance. Brent Bean does a great job in discussing some of the causes of lodging and how hybrid selection can affect it in his blog titled “Sorghum and Lodging” (see link at bottom of page).
When it comes to yield, our mantra at S&W has always been that we breed for Yield, Yield, and Yield. Now this sounds like we are trying to be humorous, but this can be further defined as Yield for maturity, Yield Stability, and Harvestable yield. When evaluating hybrid yield, data is key. We have all heard the old adage, “In God we trust, everyone else bring data”. Many people insist on local yields to select a hybrid. An analysis of state variety trials in Kansas many years ago showed that data from across a region was very useful in predicting a good hybrid to plant. We break the High Plains into three to four regions and look at hybrid performance within those regions so that we have lots of environments to evaluate a hybrid over. There are many great sources of data including university trials and seed company data. One sure way to see local data is get involved in putting out a plot with your local dealer or extension office.
I did not address maturity because most of you will be familiar with what works in your area. I try and challenge people to try longer maturing hybrids in their area after a series of droughts. When it gets dry, shorter maturing hybrids tend to yield better and then we see maturity creep downward. Keep this in the back of your mind as you look at maturities. Be sure and adjust your thinking when looking at yield data from drought-stricken locations.