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  • Author or Editor: John Stenger x
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Traditionally, the structure of higher-order data in genotype-by-environment interaction requires simplification to use bilinear reduction models. Flexible multiway reduction models have been claimed to be more informative, as they allow exploration of individual trends and account for the covariance among data modes. In complex latent traits, such as acclimation response of grapevine (Vitis sp.), these methods may offer increased insight into plant adaptive processes. In a growth chamber study, data from seven phenotypic traits at 11 photoperiodic times in the presence of two temperatures of 30 accessions were analyzed. The four-way interaction among these data modes was isolated and further examined through bilinear singular value decomposition (SVD) and multiway Tucker decomposition models. A similar set of three latent process traits were identified regardless of model used. The Tucker decomposition model led to more concise clustering of wild-type accessions, was more interpretable, as trends could be evaluated separately, and had less indication of overfitting; therefore, the multiway method was preferred over the standard SVD bilinear method in the investigation of high-order interaction in acclimation response. This methodology may offer insight into other complex traits, such as phenolic development, drought tolerance, and horizontal disease resistance to improve breeding efforts as other individual mechanisms used by the organism are separated, quantified, and compared rather than the culmination of events as an end-product.

Open Access

Elemental sulfur is commonly applied for powdery mildew (Erysiphe necator) protection on winegrape (Vitis sp.). The product may be used in a diversified, integrated disease management system to help prevent fungicide resistance to products with other modes of action. Additionally, sulfur may be used as a control option in organic systems. Applications of sulfur have been known to cause phytotoxic injury to susceptible winegrape cultivars, particularly those stemming from fox grape (Vitis labrusca) parentage. To improve recommendations to producers in the northern Great Plains region of the United States, a comparison of injury incidence and severity, as well as effects on yield characteristics was undertaken for 13 regional cultivars exposed to three sulfur rates (0, 2.4, and 4.8 lb/acre a.i.) at a North Dakota State University Research Station near Absaraka, ND. Overall, four cultivars (Bluebell, Baltica, Sabrevois, and King of the North) of the 13 cultivars tested showed phytotoxic symptoms. Injury severity and incidence of these cultivars differed between years and across rates. ‘Bluebell’ showed consistent and severe sulfur injury symptoms. Injury to the other three susceptible cultivars tended to vary by the given environment, with King of the North generally showing the lowest injury response. Injury symptoms were not found to be associated with the overall yield or cluster weight. Results suggest that alternative spray programs that exclude sulfur-based fungicides should be recommended for ‘Bluebell’, ‘Baltica’, ‘Sabrevois’, and ‘King of the North’, whereas sulfur-based fungicides may be applied to ‘Alpenglow’, ‘ES 12-6-18’, ‘Frontenac’, ‘Frontenac Gris’, ‘La Crescent’, ‘Marquette’, ‘Somerset Seedless’, ‘St. Croix’, and ‘Valiant’. Observations on fruit ripening in 2014 suggest that future research is needed to determine if a reduction of fruit quality may occur in some seasons with repeated sulfur applications or with successive annual sulfur applications for susceptible cultivars if used in an organic production system.

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Field trials using sublethal doses of glyphosate, dicamba, or mixtures of both herbicides on dry edible pea (Pisum sativum), dry edible bean (Phaseolus vulgaris), and potato (Solanum tuberosum) were conducted at six locations to determine the injury potential if spray drift were to occur. All studies used three increasing sublethal doses of glyphosate and dicamba, which were labeled as low, medium, and high. The doses for each herbicide varied for the three crops because of expected sensitivity differences. Herbicide doses were targeted for the reproductive stage 1 with dry edible pea and dry edible bean, and at tuber initiation for potato. Visible injury 20 days after the treatment ranged from 0% to 13% for dry edible pea, 0% to 53% for dry edible bean, and 0% to 50% for potato. Compared with the nontreated, yield was least when doses included dicamba, regardless of the crop. Dry edible bean was the most sensitive crop to sublethal doses of dicamba, followed by dry edible pea and potato. Results from these six studies suggested that drift injury potential to dry edible pea, dry edible bean, and potato will be greater if a dicamba-resistant soybean (Glycine max) crop is adjacent and upwind compared with a glyphosate-resistant crop. Results also reinforce the need for diligence in the application of these herbicides in proximity to susceptible crops and the need to thoroughly clean sprayers before spraying a sensitive crop.

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