never been rated for Al tolerance (Palmer et al., 1996). The few soybean germplasm evaluations to date indicate Screening methodology remains a practical barrier in the breeding that soybean can be screened for tolerance to Al-rich of Al-tolerant soybean [Glycine max (L.) Merr.]. Our objectives were to (i) develop a repeatable sand-media culture method for Al toler-acid soil with some degree of success (Sartain and Kamance screening of plants, (ii) compare Al response of genotypes in prath, 1978;Hanson and Kamprath, 1979; Campbell and sand culture to a standard hydroponics-based seedling culture, and Horst and Klotz, 1990;Foy et al., 1992, (iii) establish a practical guide for the use of hydroponics and sand-1993b; Spehar, 1994). However, genotypic rankings for culture screening methods in the selection of Al-tolerant soybean. We Al tolerance often vary among soil types. developed a sand-media culture method and imposed 0 and 450 M Aluminum saturation, the percentage of cation-ex-Al 3؉ activity treatments upon 10 diverse soybean genotypes. The exchange capacity occupied by Al, has been employed in periment employed a randomized complete block design with nine recent decades to classify the potential for Al toxicity replications. Root weight and relative root surface area (RRSA) were in soils, but it has not helped soybean breeders to predict determined at 18 d after transplanting (DAT). In hydroponics, the changes in genotypic rankings for Al tolerance that may genotypes were compared for taproot elongation after 3 d of exposure to 0, 2, and 5 M Al 3؉ activity treatments in a split plot design with occur from one soil type to the next (Kamprath, 1984; six replications. Aluminum stress was imposed successfully (approxi-Fageria et al., 1988). Researchers have attributed dismately 57% of the growth in control) in hydroponics and sand culture, crepancies in genotype rankings to the different concenbut discrepancies between methods were apparent. The hydroponicstrations of Al, P, Ca, Mg, organic acids, and other soil based seedling screen produced an inflated range of genotypic response components which greatly affect and potentially mask and altered Al tolerance rankings in comparison with sand culture.

BackgroundCreep feeding is used to stimulate piglet post-weaning feed consumption. L-Glutamine (GLN) is an important source of fuel for intestinal epithelial cells. The objective of this study was to determine the impact of creep feeding and adding GLN or AminoGut (AG; containing glutamine + glutamate) to pre- and post-weaning diets on pig performance and intestinal health. Litters (N = 120) were allotted to four treatments during 14–21 d of lactation: 1) No creep feed (NC, n = 45); 2) creep fed control diet (CFCD, n = 45); 3) creep fed 1% GLN (CFGLN, n = 15); 4) creep fed .88% AG (CFAG, n = 15). After weaning, the NC and CFCD groups were sub-divided into three groups (n = 15 each), receiving either a control nursery diet (NC-CD, CFCD-CD) or a diet supplemented with either GLN (NC-GLN, CFCD-GLN) or with AG (NC-AG, CFCD-AG). Litters that were creep fed with diets containing GLN or AG also were supplemented with those amino acids in the nursery diets (CFGLN-GLN, CFAG-AG). Glutamine was added at 1% in all three post-weaning diet phases and AG was added at .88% in phase 1 and 2 and at .66% in phase 3.ResultsFeed conversion (feed/gain) showed means among treatment means close to significance (P = 0.056) and Tukey’s test for pairwise mean comparisons showed that Pigs in the CFGLN-GLN group had the best feed conversion (feed/gain) in the first three-week period post-weaning, exceeding (P = 0.044) controls (CFCD-CD) by 34%. The NC-AG group had (P = 0.02) the greatest feed intake in the last three week of the study, exceeding controls (CFCD-CD) by 12%. CFGLN-GLN, CFCD-GLN and sow reared (SR) pigs had the greatest (P = 0.049) villi height exceeding the CFCD-AG group by 18%, 20% and 19% respectively. The CFAG-AG group had the deepest (P = 0.001) crypts among all treatments. CFGLN-GLN, CFCD-GLN and SR groups had the greatest (P = 0.001) number of cells proliferating (PCNA) exceeding those in the NC-CD group by 43%, 54% and 63% respectively. Sow reared pigs showed the greatest (P = 0.001) intestinal absorption capacity for xylose and mannitol.ConclusionSupplementation of creep feed and nursery diets with GLN and/or AminoGut in the first three week improved feed conversion possibly due to improved intestinal health.

Deoxynivalenol (DON) concentrations in mature wheat grain are usually correlated with symptoms produced by Gibberella zeae infection. However, there have been numerous observations of unacceptably high DON in asymptomatic crops, which can lead to lower-than-expected milling reductions in DON. We conducted a field experiment with winter wheat to examine the effect of infection timing and postanthesis moisture on grain quality and DON accumulation. Seven to eight soft red winter wheat cultivars were grown in three successive years in a misted nursery in Kinston, NC. Spikes were randomly selected for individual spray inoculation at 0, 10, or 20 days after anthesis (daa). Starting at anthesis, plots were subjected to 0, 10, 20, or 30 days of mist. Inoculated spikes and noninoculated controls were collected at harvest-ripeness, and the threshed grain was assayed for Fusarium-damaged kernels (FDK) and DON. In 2 of 3 years, percentages of FDK were significantly lower from 10-daa infections than from those at 0 daa, although DON concentrations were the same at the two inoculation timings in 2 of the 3 years. Those results indicate that the period of maximum susceptibility to wheat spike infections by G. zeae is close to or slightly less than 10 daa in North Carolina. In 2 of 3 years, FDK-DON correlation was greater for 0- and 10-daa inoculations and for 0- to 20-daa misted treatments than for the later-inoculated or longer-misted treatments, respectively. The percentage of "low-FDK, high DON" (LFHD) observations (defined as FDK < or = 4.0%, DON > or = 2 microg g(-1)) was higher in 2007 than in 2005 or 2006 (41, 14, and 18%, respectively). In both 2006 and 2007, high percentages of LFHD observations (> or = 60%) occurred under marginal disease conditions involving late infection. We conclude that late infection is an important factor leading to LFHD grain. Periods of rain soon after anthesis likely favor the low-symptom, high-DON scenario, and conditions that create greater within-crop variability of anthesis timing may also be important.

RESEARCH S t. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is widely used as a lawn grass in warm, tropical, and subtropical regions of the world (Sauer, 1972). It is a popular choice for lawns in the southern United States due to its aesthetically pleasing appearance and shade tolerance (Busey and Davis, 1991; Trenholm and Nagata, 2005). However, St. Augustinegrass is prone to thatch accumulation (Horn et al., 1973), which is conducive to insect and disease problems (Haygood and Martin, 1990). The southern chinch bug (SCB, Blissus insularis Barber) is the most economically important insect pest of St. Augustinegrass and is found throughout the Gulf States, from Texas to Florida and further north into Georgia and North Carolina (Henry and Froeschner, 1988; Sweet, 2000). Southern chinch bugs have piercing-sucking mouthparts and feed on the phloem of grass plants within meristematic tissues (Painter, 1928). In doing so, SCB deposit their salivary sheaths in the plant tissue at the site of feeding (Backus, 1988). These insects normally reside in the thatch area of the turfgrass stand and prefer to feed on the lower leaf sheaths and crown area of the plant (Anderson et al., 2006). Affected areas turn yellow, then brown, and ultimately die. As the season progresses, these areas can coalesce into large areas or entire lawns of dead grass (Reinert et al., 1995).