Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/2/1995
Publication Date: N/A
Technical Abstract: Protein content of soybeans (Glycine max L.) grown in Northern production areas often is lower than required for high-protein meal. Our early studies revealed that low seed protein content was not caused by a limited capacity of the developing embryo to take up amino acids, even at low temperatures. Recent studies show that commercial genotypes which typically produce seeds swith 32 to 34% protein in the field have the genetic potential to accumulate up to 40% seed protein when grown at 35 deg C during seed fill. The ratio of sucrose:glutamine uptake in vitro remains fairly constant (about 2:1) at growth temperatures from 20 to 35 deg C. Thus, relative rates of sucrose and glutamine uptake alone did not explain the variation in final seed composition with temperature. At 20 deg C, twice as much sucrose was metabolized into oil as into protein. At 35 deg C however, twice as much sucrose was metabolized into protein as into oil. Relative incorporation of carbon from glutamine into protein vs. oil also increased with temperature. These results show growth temperature alters the partitioning of glycolytic and amino carbon into protein and oil metabolism within the developing embryo.