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The development of dark color is often a major problem in the processing of potatoes. This is due, in large part, to the reaction of reducing sugars with amino acids upon the application of heat during processing. Several chemicals have been shown which, when applied to foliage in the field, will decrease reducing sugars and dark color in processed potatoes.
Arizona Farm Safety Day has been held annually since 2000 as an attempt to educate students and farm workers (pesticide applicators, tractor and equipment operators, irrigators, and field workers) in farm safety. Our programs have emphasized tractor safety, pesticide safety, ATV safety, electrical safety, and firearms safety. The all-day events have been held in Yuma and in Safford, Ariz., and most of the attendees are high school students. Agriculture students from six to eight high schools typically participate. The agenda is determined by consulting with local agriculture leaders. Attendees have the opportunity to attend a 4-hour training session in the morning. Subjects taught at these sessions might include reading a pesticide label, sprayer calibration, wearing proper protection, avoiding spray drift, tractor safety, and farm safety. At least one of these sessions is an outdoors “hands-on” session. Individual participants receive up-to-date information and literature, a certificate of completion, CEUs, CCA credits, a hat, and a lunch. Spanish translation is available at each session. In the afternoon, a tractor driver safety course and equipment demonstration is typically held. In the course, selected representatives from local farms or local youth get a chance to demonstrate their tractor and ATV driving and safety skills for recognition and awards. Plaques and trophies are awarded to the winners. Additionally, there is an equipment demonstration. Attendees are tested before and after the event.
Abstract
Hardwood and softwood pecan cuttings were exposed to various preconditioning treatments prior to propagation. Some softwood cuttings girdled and those girdled and etiolated, rooted and/or retained their leaves. These were the only softwood cuttings that retained their leaves throughout the rooting period. Cuttings from other treatments displayed no rooting activity.
Three to 4 areas of endogenous rooting-cofactor activity corresponding to specific Rf values were located in basal extracts of all cuttings by paper chromotography and the mung bean rooting bioassay. Two consistent areas of root inhibitory activity corresponding to specific Rf values were evident in cuttings from all preconditioning treatments, except one. Cool temperature storage of hardwood cuttings removed the root-inhibitory activity in one of these areas.
A compound similar to juglone was extracted from leaves and stems of the pecan stock plants. This compound was associated with one of the areas of root-inhibitory activity. “Units of promotion,” values based upon the relative amounts of endogenous root promoting cofactors and rooting inhibitors present, were reliable indicators of rooting potential. Factors other than rooting-cofactor compounds appear to limit the rooting of pecan cuttings. The presence of root inhibitory substances appears to play a significant role in the rooting complex of pecan stem cuttings.
Abstract
A longitudinal splitting of pecan which causes loss of nuts of thin-shelled cultivars during the “water” stage of the kernel is described. A similar splitting was induced by forcing water into the nut with a hypodermic needle. Soaking of nuts in water either on or off the trees did not induce splitting.
Runners from 318 plants representing 37 populations across the northern tier of US states, from Washington to New York, were collected and planted in two replications in a common greenhouse environment to assess morphological variation among octoploid strawberries (Fragaria chiloensis, F. virginiana spp. glauca and F. v. spp. virginiana). DNA was also extracted from these plants to determine molecular variation using RAPD's (Random Amplified Polymorphic DNA). Preliminary data suggest that the following morphological characters are useful traits in assessing diversity: flowering and runnering date; sex; petiole and peduncle hairs; petiole and peduncle color; leaf color, size, shape and density; and powdery mildew resistance. Preliminary RAPD data has revealed many useful molecular markers capable of detecting variability from the intrapopulation to interspecific level. Analysis of these data will determine relative genetic distances among the populations and provide a more complete understanding of the diversity available to the strawberry breeder in the octoploid taxa native to North America.
Herbicide use is an important component of weed management in field nursery crops. No single herbicide controls all weed species. Oxyfluorfen, simazine, and isoxaben are preemergence herbicides effective against broadleaf weeds. Oryzalin, pendimethalin, and prodiamine are effective in preemergence control of grasses and some small-seeded broadleaf weeds. Metolachlor is the only herbicide currently labeled for nursery crops that is effective in preemergence nutsedge (Cyperus) control. Fluazifop-butyl, sethoxydim, and clethodim are selective postemergence herbicides used for grass control. Glyphosate, paraquat, and glufosinate are nonselective postemergence herbicides used in directed spray applications for broad-spectrum weed control. Bentazon, halosulfuron, and imazaquin are effective postemergence nutsedge herbicides. These herbicides are discussed with respect to their chemical class, mode of action, labeled rates, and current research addressing their effectiveness in nursery crops.
Restriction fragment-length polymorphisms (RFLPs) of chloroplast DNA (cpDNA) were used to study phylogenetic relationships among twenty-six Fragaria taxa and two closely related species, Potentilla fruticosa L. and Duchesnea indica (Andrews) Focke. Sixteen restriction enzymes and probes of the entire Nicotiana tabacum L. chloroplast genome revealed a very low level of variation among the Fragaria taxa, limiting phylogenetic resolution. However, Fragaria appears to be more closely related to Potentilla than Duchesnea. The diploid taxa, F. iinumae Makino, F. nilgerrensis Schlect. and F. vesca L. were the most divergent Fragaria taxa and F. iinumae appears to be the most ancestral taxon. Little variation was revealed within the economically important octoploid group of taxa, which gave rise to the cultivated strawberry, and no progenitor taxa to the octoploid group could be identified. The lack of variation in the chloroplast genome suggests that these Fragaria species may be of relatively recent evolutionary origin.
Grape phylloxera (Daktulosphaira vitifoliae Fitch) was studied in three infested, self-rooted, European wine grape (Vitis vinifera L.) vineyards in western Oregon. Bi-weekly sampling of infested roots at two depths (15-30 cm and 30-45 cm) was done during the growing season in 1992 and 1993. Centrifuged laboratory extractions of insects were seperated into life stages and counted. Results indicate hibernants emerged in April/May when soil temperatures varied from 8 to 21°C. Viable eggs were recovered in June/July. Alates and above ground crawlers were found on sticky trunk wraps in July/August. It appears there were three generations of phylloxera with the third being significantly smaller. Replicated laboratory colonies were reared at 5 temperatures (7, 10, 13, 16, 21 °C). Reproductive rates will be contrasted with field populations.
Experiments were conducted in Auburn, AL, and Aurora, OR, to evaluate herbicides for pre-emergence liverwort (Marchantia polymorpha) control. Granular pre-emergence herbicide efficacy varied by location and product. Summarizing across all experiments, flumioxazin and oxadiazon provided the most effective control in Alabama, whereas flumioxazin and oxyfluorfen + oryzalin provided the most effective control in Oregon. Sprayed quinoclamine provided pre-emergence liverwort control, but efficacy and duration of control were reduced compared with granular herbicides.