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Sorghum- Already endowed with drought-tolerant traits
Global warming garners headlines just as drought tolerant corn is a hot topic in agricultural circles, but National Grain Sorghum Producers Foundation President Dr. Bruce Maunder believes that Sorghum is a crop that’s already ahead of its time when it comes to tolerating higher temperatures and needing less water. As the former Sorghum Research Director for DEKALB, Maunder is quite familiar with the challenges facing farmers in the Sorghum Belt or middle section of the country. “Sorghum was introduced into the United States from about 1880 to 1910. As the railroad moved across the country, more farmland was developed in the Great Plains and it soon became obvious under high temperatures and less rainfall that another crop besidescornwas going to be required to produce grain for livestock feed. Therefore, Sorghum was introduced to this country as a replacement under more stressful conditions for corn. It just is an obvious crop for these challenges that we may be facing with higher temperatures and less water.”
Maunder said he is not necessarily a believer in the theory of global warming, but he does believe that the earth “cycles,” having times of higher temperatures and then reverting back to times of cooler temperatures. He said that Sorghum will still manage to produce a crop even when it faces extreme conditions in the course of the growing season.
“Corn, sorghum, and sugarcane are what we call C4 plants. Small grains such as Soybeans and other crops are C3. C4 plants are more water-use efficient than C3 plants, about twice as water-use efficient, so they have a head start.”
“If you start to look at the difference between corn and sorghum… as the temperature gets higher,corn becomes more sterile so you have less pollination whereas Sorghum favors higher temperatures for more fertility in the crop and better pollination. Dormancy is a trait of sorghum. It will sit and wait and not show as much stress as other crops when it gets too dry or too hot. Shutting down the small stomates, or pores, in the leaves to avoid transpiration and water loss is a difference between corn and sorghum, not only in the number of these small pores, but their location on the plant. The Sorghum plant seems to be able to tolerate higher leaf temperatures without damaging the crop, so it can close these pores during the heat of the day more and can avoid water loss. We’ve seen that in some of the more drought resistant sorghums.”
Sorghum also presents some advantages to plant breeders because it is a crop that thrives in hot, dry environments such as Africa.
“Fortunately, there’s a lot of diversity in the Sorghum world collection with over 40,000 different sorghums. We know that these things evolved in Africa over thousands of years, and there couldn’t be too many more stressful conditions for both moisture and temperature across that continent. The big challenge to plant breeders over these years has been to find those traits and incorporate them into products that are going to be grown by producers. Also, there have been some tests developed that allow plant breeders to screen their material for tolerance to high temperature. So, we do have some real opportunities in that regard.”
Sorghum research garners less investment dollars than other crops to further exploit sorghum’s drought-tolerant traits, improve yield and control grasses. Private industry investment, producer checkoff dollars from seven states, federal appropriations and funds from the National Grain Sorghum Producers Foundation are being used to help move the crop forward. In addition, the National Sorghum Producers has submitted a proposal to USDA to create a national Sorghum checkoff that would make a significant difference in the funds available for research.
“Short term, we are thinking a lot about things such as ethanol and grain supply to meet the demands. Where are looking at more arid parts of the country where a lot of these ethanol plants are being developed (Kansas, Colorado, Western Nebraska, the Texas Panhandle, and New Mexico), this extra heat tolerance that we currently have is going to be a big benefit in water-use efficiency.”
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