b'in the seed, says Rajcan, but though theThe Way Forwardvariety proved successful with majorDiers has been studying quantitative trait markets for food-grade soy, it onlyloci (QTLs), regions of DNA associated reached yields of about 85% to 90% ofwith particular traits, for protein since he those seen by high-yielding oilseed typewas a grad student in the late 1980s. His soybean varieties at the time. work is focused on finding QTLs that influ-In the 2000s, the message to theence protein and yield so soybean breed-Canadian industry changed, says Rajcan:ers can make better selections.buyers said they were willing to buy soy atDiers says there are many genes in 43% or 44% protein (on a dry bean basis)soybean that contribute to protein. Most as long as there were no major yield penal- of these have a very small effect, so if you ties theyd have to cover with premiums. make a cross between two varieties youll The Canadian industrys researchobserve a distribution of protein among efforts shifted to discovering whetherexperimental lines, he explains. genetics from high-protein breeding mate- But there are large-effect QTLs too, rial like Harovinton could be combinedincluding those found on chromosomes 15 Nadia Krasheninnik, a researchwith that of high-yielding material.and 20, he adds. The QTL on chromosome scientist for Corteva Agriscience,What we found out was that when20 has the largest effect on soybean pro-says the company has beenone reaches 45% protein and above intein, with protein increases up to two per collaborating with the Unitedthe seed, that comes with a yield pen- centbut theres an associated decrease Soybean Board on the Upperalty, says Rajcan. There are some goodin seed yield. Midwest Protein Improvementhigh-yielding varieties with 44% or 43%Environmental variation does seem to Initiative for the last four years.protein, and theres no yield penalty. have an impact, however: Diers says some Whats so magical about this 45%work in the southern states has shown a barrier, Rajcan asks? There are someless negative effect on yield. genes and alleles that increase protein toDiers believes the path forward in the those very high levels that happen to beU.S. will have to involve incentives for linked on the chromosome with lowerfarmers to grow higher-protein varieties. yield, he explains. When you push theWe see a range of protein in high boundaries, youll have a high proteinyielding germplasm. If there were incen-allele linked tightly on the chromosometives for farmers to grow just the higher with very low yield and the linkageprotein varieties, we could make some cannot be easily broken. Youll have aprogress, he says. I believe that we will yield penalty. likely see a continued drop in protein Soybean breeders have been criticizedlevels over time unless there are incentives in Canada and the U.S., Rajcan says, forfor focusing more on protein.failing to produce soy that yields as wellDiers program currently tests soybean as corn. But soys yield limitation is physi- lines for protein and yield and identifies ological: soybean plants simply cannotpromising lines. But there are public breed-produce yields as high as corn. Anders in the U.S., including at the University of theres another reason soy yields and yieldNebraska, who are looking at diverse germ-increases lag behind corn: corn is grownplasm with the goal of increasing soybean Istvan Rajcan, a professor ofas a hybridit is a C-4 plant (mean- protein with minimal impacts on yield. soybean breeding and genetics ating higher photosynthetic efficiency) andPrivate breeders are also focused on the the University of Guelph, says histhe plant benefits from hybrid vigour.problem. non-GM soybean program makesSoybean, a C-3 plant, is self-pollinated.According to Chris Davison, Syngentas selections that emphasize yield,Rajcans program is entirely focused onhead of business sustainability for North hilum colour and soybean cystconventional non-GM soybeans in orderAmerica, protein levels are influenced by nematode resistance. to avoid seed contamination issues. Hismore than just genetics. program makes selections that empha- There are a number of factors that size yield, hilum colour and soybean cystdetermine protein levels that are seen in nematode resistance. They select large- any given year. They include, but are not seeded soybeans good for tofu productionlimited to, the variety, weather and loca-but also smaller seed sized soybeans thattion of fields, he says. As a general rule, are high yielding and maintain an averagefewer days to maturity translates to lower of about 42% to 43% seed protein. Theyprotein levels.also develop small seeded natto varietiesThe key, Davison says, is to get the bal-for the Japanese market. ance right. Historically, our focus on pro-24GERMINATION.CAMARCH 2020'