Location: Southern Horticultural Research
2013 Annual Report
Selected disease control chemicals, pyraclostrobin + boscalid (Pageant) and an extract of Reynoutria sachalinensis (Regalia SC), were evaluated for their ability to enhance drought tolerance of greenhouse-grown tomato and impatiens under water stress. Fungicides were foliar applied once a week for 4 weeks at selected rates. Impatiens were evaluated by maintaining soilless substrate moisture levels at 85% (well-watered), 55%, or 25% [based on total volumetric water content (TVWC)] or by watering to 85% TVWC at 1 (daily), 3 or 6 days between watering (DBW); tomatoes were maintained at either 85% or 55% based on TVWC. Pageant did not enhance drought tolerance compared to nontreated plants; however, shoot dry weight of well-watered (85% TVWC) impatiens was greatest with application of the 1.0× rate and the 0.5× rate of Pageant increased root dry weight of impatiens watered with 6 DBW. Similarly, tomatoes and impatiens treated with Regalia SC did not exhibit enhanced shoot growth compared with nontreated plants; however, application of Regalia did result in increased chlorophyll content, a higher photosynthetic rate, and greater soluble protein content in moderately stressed (55% TVWC) plants. Although previous reports have indicated increased yield, enhanced root growth, or increased drought tolerance after using these fungicides with field crops, such results were not found in this controlled-environment study, information which will be useful to growers considering these chemicals for greenhouse crops.
A study examined hardwood cutting propagation of the ornamental shrub Hibiscus mutabilis (confederate rose). Propagation of this species using stock plants during the winter in areas where stems from the previous season's growth are not killed by cold winter temperatures would permit maximum use of propagation materials for the rapid multiplication of new cultivars by supplementing, or being used in place of, leafy stem cuttings taken during the growing season. Cuttings in the study received a 1-second basal quick-dip in auxin [1000 parts per million (ppm) indole butyric acid (IBA), 3000 ppm IBA, 1000 ppm IBA + 500 ppm naphthaleneacetic acid (NAA), and 3000 ppm IBA + 1500 ppm NAA] and a basal wound (along with 1000 ppm IBA only) and were rooted in a greenhouse. Auxin treatments improved overall rooting percentage and total root length, with 1000 ppm IBA (without and with a basal wound) providing the highest rooting percentages and nontreated cuttings the lowest. A significant increase in total root length on rooted cuttings resulted with the use of 3000 ppm IBA and use of a basal wound plus 1000 ppm IBA compared with nontreated cuttings. Auxin and wounding treatments did not have any significant inhibitory effects on bud break and growth of new shoots on rooted cuttings. This information will be useful to nursery growers in maximizing available propagation material for the rapid multiplication of this crop.
In addition, the Beaumont Horticultural Unit (BHU) hosted a Muscadine Field Day in 2012 and a Muscadine Pruning Workshop in 2013 in collaboration with Mississippi State University (MSU) Small Fruits Extension Specialist scientist. Because of the growing interest in fruit production, a third high tunnel was constructed this summer and will be used for perennial fruit production. Also, three grape varieties were added to the muscadine vineyard for long-term evaluation.