b'Another set of experimental varieties will go inreaching roots allow plants to access moisture and the ground next year and Brummer hopes some ofnutrients far below the surface, helping them thrive those will be worth releasing out to the commercialin dry conditions and withstand extreme heat. sector.This is important because as the climate The next couple of years will tell us a lot, hechanges, we need to be able to adapt to extreme says.weather in different regions, Xu says.Seed companies can then use this research, ensuring farmers have access to high-quality seedsNitrogen Fixation is the Secret Weaponthat perform well under changing conditions andResearchers are also focused on improving limited resources.alfalfas environmental benefits, including carbon In the public sector, were developing tech- sequestering. In fact, Xu believes the future of nologies and germplasm that will be useful for thealfalfa lies in breeding specifically for sustainabil-commercial sector, but whether we can reverse thisity benefits, but only if paired with incentives for Christina Arther,yield stagnation and acreage decline remains to befarmers to focus on those goals.USDA-ARS researchseen, Brummer says. I dont see alfalfa acreage going up unless biologist varieties are planted that allow farmers to get more Rooted in Sustainabilitycarbon sequestration and nitrogen fixation credits, Zhanyou Xu, a research geneticist in alfalfahe says.breeding with the U.S. Department of Agriculture And though Xus root structure work has not Agricultural Research Service (USDA-ARS), agreesyet been commercialized, available alfalfa varieties that drought tolerance will continue to be a keyare already effective when used as a nitrogen fix.breeding focus.Essentially, alfalfa does not require nitrogen Unlike with corn, alfalfa farmers in Californiafertilizer, says Daniel Putnam, professor emeritus of can cut the crop up to 10 to 12 times and after eachCooperative Extension in the UC Davis Department cutting, it typically needs to be watered, he says.of Plant Sciences. In fact, it does so much good for This is why breeders must focus on water usethe soil when used in a rotation that you can either efficiency. reduce or even forego a nitrogen fertilizer applica-Xus recent work has been largely focused ontion when you plant corn after alfalfa.divergent selection for the best root structure toWe would like to see alfalfa used in rotation in achieve specific goals. the Midwest, especially, because it does so much Root system architecture (RSA) representsgood for the soil, Putnam adds. Daniel Putnam, UC Davisthe second green revolution in plant breeding, Cooperative Extensionoffering significant potential for carbon sequestra- Protein Possibilitiesprofessor emeritus tion, water and fertilizer use efficiency, sustainableAlfalfa actually produces more protein per acre agriculture, and enhancing ecosystem resilience forthan any other crop, even without needing that the changing climate, Xu says. nitrogen fertilizer. Thats a real advantage, Putnam Researchers started with the original root typesays.and planted about 4,000 plants, specifically look- As such, dairy and cattle industries still rely on ing for high fibrous and low fibrous content.alfalfa as an important food source and Putnam Then, we intermated those two groups andsays alfalfa production can result in 2,500 and generated a population where we selected high3,500 gallons of milk per acre, specifically in the fibrous plants and low fibrous plants to intermate.Southwest.We planted 8,000 of each for cycle two, Xu says.But researchers are also working on expanding Eventually they ended up with four distinctmarkets by extracting protein for human consump-categories: highly fibrous tap roots, highly fibroustion. The work is still experimental, but the poten-branched roots, tap roots with low fibrous roottial is promising because of the impressive protein content and branched roots with low fibrous rootcontent.content. Alfalfa leaf protein already has many of the Right now, we are specifically selecting forfunctional properties that human consumption those that have a lot of branched and fibrous rootsrequires; however, the disadvantage is that alfalfa Charlie Brummer, UCbecause when the soil has a lot of fertility andprotein is mainly in the form of rubisco, a key Davis Center for Plantplenty of water, for example, this structure allowsenzyme in photosynthesis which degrades quickly Breeding director the plant to really absorb all those nutrients andafter harvest.fertilizer quickly for a high biomass yield, Xu says.Seed producing crops encapsulate the protein Growers can plant tap roots to enhancein the seed which are much easier to store and drought and heat tolerance, as these deep- transport after fractionation, while leaf protein 32/ SEEDWORLD.COMOCTOBER 2024'