In the previous month’s column, the causes and prevention of lodging in sorghum were discussed. Plant height was mentioned as playing a role in lodging, but the actual correlation of height and lodging is very low.
This was based on a recently published study, in Crop Science, where more than 50 years of data from Texas AgriLife sorghum variety trials was analyzed.
Another intriguing conclusion of the study was the clear and positive correlation between sorghum plant height and yield. This positive association has been well documented in other studies.
Although the exact cause of this association is unknown, the hypothesis is that taller plants have longer internodes, resulting in a greater distance between leaves. This distance allows for better light capture, resulting in improved photosynthesis that results in improved yield.
If increased height is associated with higher grain yield, then why are growers reluctant to plant taller hybrids? The most often cited reason is because of the perception that increased height will lead to lodging. While common sense does tell us that increased plant height must increase the risk of lodging, the results of the analysis of this extensive dataset strongly suggests that the risk is minimal. As discussed in last month’s column, there are many other factors that influence the likelihood of the occurrence of sorghum lodging.
When selecting a hybrid for planting in 2025, consider planting a taller hybrid. In the Texas A&M study, the average height of the sorghum varieties tested was 48 inches. By simply increasing the plant height 6 inches, yield was increased 900 pounds, or 16 bushels. It is important, however, that the selected taller hybrid stays within the desired maturity for your environment. Modest increases in height can be achieved without delaying the time to maturity.
Editor’s note: Brent Bean, Ph.D., is the Sorghum Checkoff director of agronomy, Lubbock, Texas. For more information, visit www.sorghumcheckoff.com.
