Rooted rabbiteye blueberry cuttings were transplanted to 15 cm pots containing either builders sand or 80% sand 20 peatmoss v/v (1% OH). Five different herbicides were applied at the high and low recommended rates. Terbacil at 1.4 or 2.9 kg/ha a.i. caused a 72% mortality while 1.8 or 3.6 kg/ha a.i. application of norflurazon caused a 53% mortality. Root volume, weight, top weight, and leaf chlorophyll concentrations were reduced by terbacil treatment. Oryzalin at 2.7 kg/ha a.i. or norflurazon at 3.6 kg/ha a.i. reduced root and top weight and chlorophyll. Napropamide at 2.2 kg/ha a.i. reduced top weight and chlorophyll. Two good choices for young plants appear to be simazine at 1.8 kg/ha a.i. and napropamide.
D.G. Himelrick and W.A. Dozier Jr.
A.L. Busby, D.G. Himelrick, and D.J. Eakes.
Two cultivars of blackberry (Rubus sp.) were propagated in July under intermittent mist by rooting 2-node softwood stem cuttings. Differences in root development among cultivars were evident with the thornless erect cultivar, `Navaho', producing a better root system than the thorny erect cultivar, `Cheyenne'. Treatment of `Navaho' with 3000 and 8000 ppm indolebutyric acid (IBA) in water and treatment of `Cheyenne' with 8000 ppm IBA in water and 3000 ppm IBA in talc improved rooting.
R.C. Ebel, D.G. Himelrick, A. Caylor, and J. Pitts
The surfactant “Surfactant WK” (dodecyl ether of polyethylene glycol) was applied to peach trees [Prunus persica (L.) Batsch] at full bloom over 3 years. Blossoms died rapidly so that within 2 days dead blossoms could be distinguished easily from live blossoms or set fruit. There were strong (R 2 > 0.87), linear correlations between concentration of “Surfactant WK” applied and percent blossoms removed and fruit set, which were similar over the 3 years. Trees were hand-thinned according to commercial practices after treatment. There was similar cropload, fruit weight, and yield across treatments at harvest indicating no negative effects by the chemical on productivity. There was only slight limb damage at the highest concentrations of “Surfactant WK,” which overthinned blossoms. We recommend that based on the effectiveness, consistency, and lack of significant phytotoxicity, “Surfactant WK” be reevaluated as a thinning chemical for peach trees.
D.G. Himelrick, W.A. Dozier Jr., and A.W. Caylor
Own-rooted four-year-old kiwifruit plants (Actinidia deliciosa) protected by a Reese clip-on styrofoam insulation trunk wrap, or microsprinkler irrigation, sustained less freeze injury than unprotected plants under field conditions at temperatures as low as -17.8C. Trunk splitting occurred on the plants but no injury was detected on canes, buds, or shoots in the canopy of the plants. Unprotected plants had more trunk splitting and at greater heights than protected plants. New canes developed from suckers of cold-injured plants and developed a filled canopy the following season.
J.L. Sibley, D.G. Himelrick, and W.A. Dozier Jr.
Poultry and coal production are two major industries concentrated in north-central Alabama. Standard surface coal mine reclamation procedures were compared to procedures utilizing poultry litter in an 3.24-ha mine site. Three 0.4-ha plots amended with litter at rates of 25, 50, and 100 mt/ha, were compared to a plot with mineral fertilizer (13N–13–P13K) at standard reclamation rates of 672 kg/ha, and a plot receiving no fertilizer or litter. All plots were amended with ground limestone and disced in 31 cm. A mix of fescue, lespedeza, rye, and clover was broadcast over all plots uniformly. Eight tree species; northern red oak, nuttall oak, willow oak, red maple, yellow poplar, royal paulownia, loblolly pine, and eastern red cedar were planted in all plots at 1482 trees/ha. Forage yields (1995–96) in litter-amended plots were two to three times higher than statewide hay production averages. High litter rates have had no negative effects on ground cover, tree survival, or ground water nitrates (NO3). This project demonstrates broiler litter use as an organic-matter amendment in a self-sustaining reclamation success.
F.M. Woods, D.G. Himelrick, R. Aynaou, G.E. Boyhan, and T.M. Brasher
Changes in the activities of sucrose-metabolizing enzymes as related to ontogeny and ripening were studied in fruit mesocarp tissues of watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai, cvs. A.U. Producer and Sweet Scarlet]. The levels of soluble sugars and the activities of sucrose synthase (SS; EC 220.127.116.11), sucrose-phosphate synthase (SPS; EC 18.104.22.168), and invertase (INV; EC 22.214.171.124) were measured. The temporal pattern of these enzymes relative to the levels of soluble sugars were similar for both cultivars. `Sweet Scarlet' was characterized by having higher INV and SPS activities, while SS activities tended to be similar in both cultivars during fruit development. During later stages of ripening, `Sweet Scarlet' tended toaccumulate reducing sugars, while `AU Producer' tended to accumulate sucrose and therefore had lower sucrose-cleaving enzyme activity. Results indicate that SPS and INV appear to play a prominent role in carbohydrate metabolism in developing and ripening tissues of watermelon.
X. Zhang, F.M. Woods, R.C. Ebel, D.G. Himelrick, N.K. Singh, and C. Mosjidis
A prevailing hypothesis indicates that a decrease in vegetative growth and cessation in floral initiation in strawberry in response to changes in photoperiod and temperature may correlate with hormonally induced changes. We investigated changes in endogenous free polyamines in crowns, flowers, leaves, and fruit of springbearing strawberries (Fragaria xananassa cvs. Chandler and Earliglow) in response to varying temperatures to induce flowering. Spermidine was the prominent free amine in crowns. No marked changes of putrescine, spermidine, and spermine were observed in crowns during the transition from vegetative to reproductive growth in either cultivar. In contrast, high levels of free polyamines were noted in young developing tissues such as the most recently initiated leaves, flower buds, and green fruit. When the putrescine synthesis inhibitor difluoromethylonithine (DFMO, 1 mm) was exogenously applied, levels of putrescine, spermidine, and spermine were altered in crown tissues in greenhouse experiments. These findings indicate that free polyamines may potentially be associated with the stimulation of new growth in springbearing strawberries under the present experimental conditions evaluated.
F.M. Woods, J.S. Kotrola, D.G. Himelrick, T.M. Brasher, and F.M. Basiouny
Fruit of two rabbiteye blueberries (Vaccinium ashei Read cvs. Premier and Tifblue) were analyzed at five stages of growth and development for cell wall softening enzymes in relation to pectin solubilization. The enzymes examined were β-galactosidase, cellulase, pectinesterase, and polygalacturonase. The decrease in fruit firmness was associated with increased activities of cellulase, polygalacturonase, and pectinesterase, which preceded the former enzymes. The activity of β-galactosidase remained relatively unchanged throughout. The pattern of enzyme activities from both cultivars were similar. Results from this study indicate that these enzymes may play a crucial role in overall fruit shelf life and hence postharvest marketing duration.
A.W. Caylor, W.A. Dozier Jr., G. Wehtje, D.G. Himelrick, J.A. McGuire, and J.A. Pitts
The postemergence-active herbicides lactofen, fomesafen, and acifluorfen were applied to established matted-row strawberry plants (Fragaria × ananassa) and evaluated for broadleaf weed control and foliar phytotoxicity. Strawberries were evaluated for yield and fruit quality. Treatments were applied following June renovation. All herbicide treatments resulted in acceptable control of broadleaf weeds present at the time of application; however, sicklepod (Cassia obtusifolia) germinated after herbicide application. All treatments caused foliar injury within 3 days after application. No injury symptoms were evident 21 days after treatment due to new foliage development. Fomesafen and acifluorfen were the only herbicides to suppress runner count. Yields the following year were not reduced by herbicide treatments. Chemical names used: (±)-2-ethoxy-l-methy1-2-oxoethyl 5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-nitrobenzate (lactofen); 5-[2-chloro-4-(trifluoromethyl)phenoxy] -N -(methylsu1fonyl)-2-nitrobenzamide (fomesafen); 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (acifluorfen).
W.A. Dozier Jr., R. Rodriguez-Kabana, A.W. Caylor, D.G. Himelrick, N.R. McDaniel, and J.A. McGuire
The yellow passionfruit (Passiflora edulis f flavicarpa Degener), a perennial vine grown in the tropics and subtropics, was successfully grown as an annual crop in a temperate zone. Fruit maturity was hastened by ethephon treatments to allow harvest before the mean date of the first killing frost. Maturity was advanced in a linear manner with application rates of 150, 300, and 600 ppm ethephon. Total yield was not affected by ethephon treatment; however, cull fruit producing no juice increased with increasing rates of ethephon, thereby reducing marketable yields. Soluble solids and ascorbic acid contents of the juice were not affected by ethephon treatment. Purple passionfruit (Passiflora edulis Sims) did not produce blossoms.