2009 Soybean Yield Prospects Improving
The purpose of this brief is to update our previous evaluation of yield potential for soybeans in Illinois, Indiana, and Iowa in 2009. (Irwin, Good, and Tannura, 2009). This update makes use of a crop weather model that estimates the impact of technology (trend), state average monthly weather variables, and portion of the crop planted late on state average yield. Previously, that model was used to evaluate 2009 yield potential based on planting progress, state average precipitation through June 2009, and alternative 2009 July-August weather scenarios. This update incorporates preliminary state average precipitation and temperature for July and alternative weather scenarios for August 2009. The yield forecasts for the three states are then used to project the U.S. average yield. Trend yields for 2009 for each of the three states and the U.S. are also presented. It should be noted at the outset that average July temperatures for 2009 were well below the coldest July in the sample of historical observations used to
Early Prospects for 2009 Soybean Yields in Illinois, Indiana, and Iowa
The USDA’s first forecast of the potential size of the 2009 U.S. corn crop was released on May 12 (USDA/WASDE, 2009). That forecast was based on: 1) acreage expected to be harvested for grain, which is a function of planting intentions revealed in the March 2009 Prospective Plantings report and the historical relationship between acreage planted for all purposes and acreage harvested for grain, and 2) projected yield, which USDA defined as “... the simple linear trend of the national average yield for 1990-2008 adjusted for 2009 planting progress.” The projected yield was 155.4 bushels per acre, which reflected a 1.5 bushel penalty for the slow pace of planting progress in the eastern Corn Belt. The 2009 production forecast was 12.09 billion bushels.
Inhibition of Root Growth and Polyamine Metabolism in Sunflower (Helianthus annuus) Seedlings Under Cadmium and Copper Stress
Although sunflower is usually regarded as a highly tolerant crop, impairment of root growth at initial stages of plant development may result in poor crop establishment and higher susceptibility to pathogen attack. In order to evaluate if Cd2+ and Cu2+ may impact on sunflower germination and initial root development, a pot experiment under controlled conditions was carried out. Possible involvement of polyamine metabolism in sunflower response to these stressors was also investigated. Although Cd2+ and Cu2+ treatments affect neither seed germination nor radicle emergence, sunflower seedlings grown in the presence of these heavy metals showed significant inhibition of root growth, being this inhibition greater for Cd2+. Both metals caused significant increases in proline contents at the highest concentrations tested (0.5 and 1 mM), and these increments were more pronounced for Cd2+ treatments, especially between days 3 and 10. Metals also increased putrescine (Put) contents at all concentrations assayed from the seventh day onward, causing no variations on this polyamine time-course pattern. Spermine and spermidine contents, however, were increased only by 1 mM Cd2+. Arginine decarboxylase seems to have been the enzyme responsible for Put increases under both metal treatments. This work demonstrates that initial root growth of sunflower seedlings may be significantly impaired in Cd2+ or Cu2+ contaminated soils. It also shows that polyamines are key biological compounds, which are probably involved in signaling pathways triggered under stress environmental conditions.