Effect of drought stress during seed development on charcoal rot and yield of soybean.

The primary controls for charcoal rot in soybean, caused by the fungal pathogen Macrophomina phaseolina, are to avoid drought stress and to plant a moderately resistant cultivar. The effects of irrigation and cultivar were determined in 2011 and 2013 at the Lon Mann Cotton Research Station, Marianna, AR. Four soybean cultivars (Hutcheson, Osage, Ozark, and R01581F), were planted in plots with or without added M. phaseolina inoculum and subjected to three furrow irrigation regimes: full season irrigation (Full), irrigation terminated at R5 (CutR5), and non-irrigated (NonIrr). Normalized difference vegetative index (NDVI) was measured at R3 and R6. At harvest, plants and yields were collected. Roots and stems were split and the extent of visible colonization by M. phaseolina microsclerotia was assessed in the roots with a 1-5 scale (RSS) and the percent plant height stem discoloration (PHSD) measured. Precipitation in September and October was 54 and 65% below the 30-year average in 2011 and 2013, respectively. The CutR5 irrigation treatment resulted in one less irrigation than Full each year, but CutR5 NDVI's at R6 and yields were significantly lower than those with Full and not significantly different than those of NonIrr. The CutR5 RSS ratings were greater than either Full or NonIrr. Plant colonization by M. phaseolina was negatively correlated to yield in 2011 but not in 2013. No premature plant death caused by charcoal rot was observed in either year. These results indicated that late season drought stress may be more important to charcoal rot development than drought stress throughout the season, but other factors are needed to trigger early plant death and subsequent yield losses observed in grower fields.

Impact of the Global Food Safety Initiative on Food Safety Worldwide: Statistical Analysis of a Survey of International Food Processors.

In 2000, the Consumer Goods Forum established the Global Food Safety Initiative (GFSI) to increase the safety of the world's food supply and to harmonize food safety regulations worldwide. In 2013, a university research team in conjunction with Diversey Consulting (Sealed Air), the Consumer Goods Forum, and officers of GFSI solicited input from more than 15,000 GFSI-certified food producers worldwide to determine whether GFSI certification had lived up to these expectations. A total of 828 usable questionnaires were analyzed, representing about 2,300 food manufacturing facilities and food suppliers in 21 countries, mainly across Western Europe, Australia, New Zealand, and North America. Nearly 90% of these certified suppliers perceived GFSI as being beneficial for addressing their food safety concerns, and respondents were eight times more likely to repeat the certification process knowing what it entailed. Nearly three-quarters (74%) of these food manufacturers would choose to go through the certification process again even if certification were not required by one of their current retail customers. Important drivers for becoming GFSI certified included continuing to do business with an existing customer, starting to do business with new customer, reducing the number of third-party food safety audits, and continuing improvement of their food safety program. Although 50% or fewer respondents stated that they saw actual increases in sales, customers, suppliers, or employees, significantly more companies agreed than disagreed that there was an increase in these key performance indicators in the year following GFSI certification. A majority of respondents (81%) agreed that there was a substantial investment in staff time since certification, and 50% agreed there was a significant capital investment. This survey is the largest and most representative of global food manufacturers conducted to date.

A Computer Program to Improve the Efficiency and Accuracy of Postulating Race-Specific Resistance Genes.

Gene postulation has been the most widely used technique to determine the presence of particular rust resistance genes in lines of small grains. It applies the principles of gene-for-gene specificity to determine the most probable race-specific resistance genes present in host lines. As the numbers of lines, resistance genes, and races increase, postulation based on visual comparisons of infection types becomes more complex and laborious, and errors may occur. A computer program was developed to facilitate identification of race-specific leaf rust (Lr) genes in wheat (Triticum aestivum). Seedlings of 116 contemporary lines of soft red winter wheat and 24 Thatcher isolines (each Thatcher isoline with a single Lr gene) were inoculated with 22 races of Puccinia triticina. Infection types were recorded on the standard 0 to 4 scale where infection types 3 and 4 were considered high (line was susceptible; race was virulent) and others were low (line was resistant; race was avirulent). Based on the gene-for-gene concept, lines susceptible to a particular race cannot have an Lr gene for which the race is avirulent. For each line, step 1 of the program summarized results from races that were virulent on the line to definitively exclude Lr genes from the line, and this exclusion resulted in a relatively short list of Lr genes that could be present. Step 2 of the program utilized data from races that were avirulent on the line, and the output listed the low infection types produced on the line and the isolines with Lr genes that were not excluded in step 1. Of these Lr genes, a gene was considered present if the low infection type produced on the line by one or more races matched the low infection type on the corresponding isoline. Otherwise, the gene was considered possibly present. Epistatic effects of one or more Lr genes prevented definitive inclusion or exclusion of genes considered possibly present. If the low infection type produced on the line was lower than that on any of the isolines listed in step 2, then the line was considered to have an unidentified Lr gene; i.e., a gene that was not in the set of 24 isolines. This program facilitated the objective and accurate postulation of Lr genes and could be adapted to other host-pathogen systems.