Search Results
Abstract
Application of an absorbent starch-acrylate polymer (ASAP) to bare-rooted plants of 4 Vaccinium genotypes did not affect plant height, vigor, or chlorosis, but it increased plant mortality significantly. About 25% of all plants treated with ASAP either alone or in combination with peat died during the first year after transplanting. Surviving plants grew at about the same rate as those from other treatments during the 2nd year. A V. ashei (Reade) collection from Mississippi showed least response to soil amendments. Untreated plants of this collection grew well during the 2nd growing season and compared favorably in size with ‘Tifblue’ grown in plots with peat added.
Abstract
The effects of pollen source on fruit set, berry size, seed characteristics, and potential pollen fertility were evaluated for low-chilling highbush type blueberries (Vaccinium spp.) pollinated in the greenhouse. Self-pollination of each clone, except for US79 which has low pollen viability, resulted in fruit set equal to or better than any type of cross. Berry weight and number of viable seeds per berry were not significantly higher for fruit produced from half-sib crosses than selling. Outcrosses generally produced the greatest berry weight and seed number.
Abstract
‘Southland’ flowers were significantly more tolerant to frost than 4 other cultivars of rabbiteye blueberry (Vaccinium ashei Reade). Reduced fruit set from flowers with damaged corollas could not be attributed to lack of pollination but probably was caused by freeze damage to pistils.
Abstract
Several plants in a Vaccinium ashei Reade collection were tolerant of terbacil. To determine whether the tolerance is heritable, progeny of crosses between a selection from these plants and 3 rabbiteye blueberry cultivars were compared with progeny of 3 rabbiteye × rabbiteye cultivar crosses. Significantly less leaf damage by terbacil occurred in offspring of the selection than in those of rabbiteye cultivars. Tolerance to terbacil appeared heritable, suggesting that the tolerant plants constitute usable germplasm for a breeding program. Chemical names used: 5-chloro-3-(1, 1-dimethylethyl)-6-methyl-2, 4(1H, 3H)-pyrimidinedione (terbacil).
Abstract
Fourteen rabbiteye bluberry (Vaccinium ashei Reade) cultivars were evaluated for contribution of component flower bud and fruit development stages to ripening date. Rate of bud, flower, and fruit development were estimated from the regression of flower bud stage and cumulative ripe fruit on time. Except for one instance, the best fitting curve for rate of bud development was described by a quadratic polynomial. Rate of fruit ripening was linear for ‘Bluebelle’ and ‘Centurion’; all other curves were described by quadratic equations. From the curves, Julian date of bud break, anthesis, 1st ripe fruit, and 50% ripe fruit were estimated. Intervening time periods comprised stages of development that could be evaluated for their contribution to ripening date of cultivars. Time required to complete the final development stage most influenced ripening date. Sample shoots could be utilized to select individual plants for ripening date, and repeatability of ripening date among clones is sufficient to select on the basis of evaluation in a single year.
Several concentrations of mefluidide (Embark), a plant growth regulator; sethoxydim (Poast), a grass herbicide; and triclopyr (Rely) a nonselective herbicide, were evaluated to determine if italian ryegrass (Lolium multiflorum Lam.) growth could be suppressed. Ryegrass grows prolifically during the winter in states adjacent to the Gulf of Mexico and may serve as a living mulch for strawberry (Fragaria×ananassa Duch.) and other winter crops if its growth can be controlled. Different chemicals and concentrations were screened over 5 years for their efficacy to produce living mulch. Mefluidide produced good ryegrass control but was not evaluated after Study 1 because it is designed for industrial use and does not have an U.S. Environmental Protection Agency fruit crop label. Triclopyr, which has a label for several fruit crops, was studied only in the final year and it provided desired ryegrass control at the 0.016 and 0.030 mL·L-1 (parts per thousand) rate. Prime oil (paraffin base petroleum oil + polyol fatty acid esters) concentration affected results when sprayed with various sethoxydim rates. We concluded that 0.156 mL·L-1 sethoxydim plus 0.25 mL·L-1 prime oil will control ryegrass growth at the desired level (reduce growth by 40% to 50%) for living mulch. These rates are too low to cause much ryegrass browning. Chemical names used: N-[2,4dimethyl-5-[[(trifluoromethyl)-sulfony]amino]phenyl]acetamide, 2-[1-(ethoxylmino)buty1]-5-[2-(ethylthio)propy1]-3-hydroxy-2-cyclohexen-1-one), and ammonium-Dl-homoalanin-4-yl-(methyl) phosphinate.
Annual ryegrass (Lolium multiflorum), which grows prolifically during the strawberry production season in the Gulf South, has the potential to serve as a living mulch if its growth is controlled. Sublethal dosages of Embark, a plant growth regulator, and the herbicides Poast and Rely were determined on ryegrass. Growth retardation was rated from 0 = none to 6 = dead. In 1993, all Poast dosages (1/8X – 1X, where X = 8 ml·L–1) were lethal. Embark regulated ryegrass growth, but its study was discontinued because of the unlikelihood that it could be labeled for use on strawberries. Results of the 1994 study suggested that prime oil in the spray may cause an inordinate amount of vegetative browning. In 1995, three levels of oil (1/256X, 1/64X, and 1/32X, where X = 8 ml·L–1) were used with each of four levels of Poast (0, 1/32, 1/64, and 1/128X). Increased levels of oil generally caused increased browning at each level of Poast, but no browning occurred where oil only was applied in the spray. In contrast to results in 1995, oil at 1/32X with no Poast caused considerable browning (score = 3.25) in 1996. The most desirable control (score = 2.75) was accomplished by a spray containing 1/128X Poast and 1/64X oil. The most desirable control by Rely (score = 3.25) was accomplished by 1/64 and 1/32X sprays. Rely is not labeled for strawberries although it is labeled for other fruit crops. Chemical names used: 2-[1-(ethoxylmino)buty1]-5-[2-(ethylthio)propy1]-3-hydroxy-2-cyclohexen-1-one (Poast); Paraffin Base Petroleum Oil + polyol Fatty acid Esters (Prime oil); N-[2,4dimethyl-5-[[(trifluoromethyl)-sulfony]amino]phenyl] acetamide (Embark); ammonium-Dl-homoalanin-4-yl-(methyl) phosphinate (Rely).
A muscadine vineyard planted at McNeil, Miss., in 1990 included 23 cultivars and a planting in 1992 included nine cultivars. Each entry was evaluated for eight useful traits over 4 years. The regressions of certain traits on others were performed to determine relationships that might be useful in selecting for valuable traits such as phyto-chemicals in seed. Ranges among cultivars for the traits were: harvest date—20 days, yield—33 kg per vine, berry weight—11.2 g, percent dry scar—38, °Brix—5, pH—0.5, seed per berry—1.2 and seed weight—5.5 g. The best relationship was between berry weight and seed weight.
To determine if high Zn concentrations contribute to chlorosis in blueberry, plants of rabbiteye `Climax' and southern highbush `Bladen' were fertilized in sand culture with 30, 60, 90, and 120 ppm Zn solutions at 4, 4.5, 5, 5.5, 6, and 6.5 pH. Only Zn levels significantly affected the degree of chlorosis in plant leaves. No interaction among cultivars, pH, or Zn concentration was significant. The linear response to Zn levels was significant (P = 0.0001), but quadratic and cubic responses were not significant. Cultivars and Zn fertilization levels affected Zn and Mn accumulation; however, no difference in chlorosis rating was observed between cultivars. An inverse relationship existed between Zn fertilization levels and leaf Mn content so that the total concentration of the two minerals was about the same for each fertilization level, suggesting that Mn toxicity would not be expected at high levels of Zn fertilization. We concluded that high levels of Zn may induce chlorosis in rabbiteye and southern highbush blueberry.
The organic acid composition of blueberries of three highbush (Vaccinium corymbosum) cultivars, three rabbiteye (V. ashei cultivars and nine southern highbush (V. corymbosun hybrids) cultivars or selections was determined by HPLC. Species means off the individual acids (citric, malic, succinic, and quinic), expressed as a percentage of total acid, formed profiles or patterns that are thought to be characteristic of the species. Citric (75%) was the predominant acid in highbush fruit with lesser percentages of succinic (13%), quinic (9.6%), and malic (2.7%). The percent composition of rabbiteye berries [quinic (49%), succinic (39%), citric (6.7%), malic (5%)] was distinctly different from highbush. The acid profile of southern highbush fruit reflected their V. corymbosum heritage with an acid profile similar to that of highbush. When related to a clone's pedigree, these results suggest that organic acid profiles may be a useful screening tool for studying the contribution of southeastern native species such as V. darrowi or V. ashei to the inheritance of organic acids.