Search Results
Abstract
There was no effect of rootstock on the net photosynthesis (Pn) of 1-year-old vegetative, containergrown ‘Delicious’ trees in 2 experiments. Rootstock effects on specific leaf weight (SLW) were slight in one experiment, and absent in another. There was no influence of rootstock on shoot growth, leaf number, transpiration rate (Tr) or dark respiration (Rd), each of which was determined in one experiment. These data fail to support reports of differences in Pn within a given cultivar on various rootstocks.
Thatch-mat and organic matter (OM) accumulation near the putting green soil surface impacts soil physical properties and turf performance. Excessive thatch and OM can encumber infiltration of water and oxygen into the soil profile and slow drainage of excess water away from the putting surface. Proper sampling of thatch-mat depths and OM contents is vital for management of putting green turf; therefore, a study was performed in Knoxville, TN, to derive proper sampling procedures of these important parameters using ‘TifEagle’ and ‘Champion’ bermudagrass (Cynodon dactylon × C. transvaalensis), ‘SeaDwarf’ seashore paspalum (Paspalum vaginatum), and ‘Diamond’ zoysiagrass (Zoysia matrella). ‘TifEagle’ and ‘Champion’ accumulated thatch-mat to a greater depth than ‘SeaDwarf’ and ‘Diamond’. However, ‘SeaDwarf’ had a higher OM content than ‘Diamond’ and both had higher OM contents than ‘TifEagle’ and ‘Champion’. Data generated from sampling procedures indicate that previous studies often undersampled plots for thatch-mat depth; however, previous sampling procedures have not traditionally undersampled plots for OM. Data in this study provide a range of confidence and minimum detectable difference levels which may allow future researchers to more accurately sample ‘TifEagle’, ‘Champion’, ‘SeaDwarf’, and ‘Diamond’ putting green plots for thatch-mat depth and OM content.
Abstract
Early settlers from the northeastern and midwestern United States brought popular grape cultivars such as ‘Concord’ and ‘Niagara’ (Vitis labrusca L.) to Florida in the mid-1800s. In the 1890s, the opportunity to ship fresh fruit by rail to northern markets provided an incentive to establish commercial plantings of these cultivars. Declining productivity of these vines, caused by a disease known then as vine degeneration, and the high cost of shipping eventually forced growers out of business. Nearly 30 years later, cultivars with improved resistance to fungal diseases of fruit and foliage, developed by T.V. Munson (1909) of Texas, were introduced to Florida. Subsequently, several thousand hectares of grapes were established in central Florida for the home wine-making market of the prohibition era. Vine degeneration disease once again caused Florida’s grape industry to fail (Truskett, 1926).
Abstract
The new mechanical-harvest varieties of tomatoes ‘VF-145’ and ‘VF-13L’ exhibited symptoms of K deficiency under both greenhouse and field conditions, while the older hand-harvested varieties remained free of symptoms. In the field the K-deficient varieties showed deficiency symptoms regardless of the amount of K applied to the soil. In late season the K concentrations in the petioles of the K-deficient varieties were much lower than in the other varieties. There were no differences between varieties in the rate or amount of K absorption from nutrient solutions. Root grafts indicated that there were no differences in the ability of the different rootstocks to absorb K.
Abstract
Seedlings of tomato (Lycopersicon esculentum Mill. cv. Rutgers) were agitated periodically on a gyratory shaker. Shaking plants at 175 rpm for 5 minutes once daily during the winter reduced leaf area, stem length, and water content and dry weight of both leaves and stems. This treatment was ineffective when applied during the summer. Five- to 20-minute treatments applied 2 or 3 times daily reduced growth during either season, but were more effective during winter. Responses were independent of the time of day at which treatment took place. Leaf area, stem length, water content of leaves and stems, leaf dry weight, and specific stem water content were reduced progressively relative to undisturbed controls as the shaking rate increased from 125 to 175 rpm during the winter. Leaf area, specific leaf water content, and specific stem water content were reduced by shaking at 44% of full summer sunlight, but not at 31% or 17%. Shaking enhanced specific stem weight only at 44% light, whereas stem length was reduced most by shaking at 17% light. Differences in relative plant response to shaking between summer and winter remained even when seasonal differences in solar flux density were minimized by use of shadecloth during the summer.
Growth, nutrient uptake, and yield of peach (Prunus persica) trees was evaluated in various groundcover management systems (GMSs) for three years, with and without preplant soil additions of Zn, B, and Cu. In July 1990, micronutrients (none, or 135kg Zn·ha-1+100kg Cu·ha-1+1.1kg B·ha-1) were incorporated into the upper 20 cm of a silty clay-loam soil (pH 6.7, 4% organic matter), and a fine-leaf fescue (Festuca ovina) turf was established. Trees were planted Apr. 1991, and four GMS treatments (wood-chip mulch, pre-emergence herbicide, post-emergence herbicide, and mowed turf) were superimposed upon the “+/-” micro-nutrient preplant treatments. Extractable Zn, Cu and B concentrations were greatly increased in soil of plots which had received preplant amendments. Peach leaf content of Zn, Cu and B was also greater in preplant fertilized plots in the year of planting. However, in subsequent years only leaf B (in 1992) and leaf Zn (in 1993) continued to respond positively to preplant soil treatments. No significant interactions were observed between GMS and micronutrient availability or uptake. Peach growth and yield were not affected by preplant treatments, but were substantially greater in mulch and pre-emergence herbicide plots compared with the mowed fescue turfgrass.
Abstract
Cultivar emergence base (CEB) temperatures were calculated for the tomato (Lycopersicon esculentum Mill.) cvs. G-18824 and H2134 and their hybrid progenies. Each population required a mean accumulation of 160 daily heat units above their CEB. The early emerging parent had a low CEB of 42.6°F, the late emerging parent had a high CEB of 46.1°F, and their progenies were intermediate. The CEB of each cultivar and progeny was the same at different temperatures. Inheritance was found to be quantitative and an estimated 24 gene pairs differentiated the parents for CEB. There was strong evidence for additive gene action. Dominance and epastasis were not ruled out. Broad sense and narrow sense heritability estimates were 25-40% and 25% respectively. The same gene system appears to control emergence at both low and high temperatures. Selection for emergence at low temperature could be achieved at high temperatures on the basis of CEB.
Abstract
Leaflet length and width were used to calculate leaflet area, lateral leaflet area, and trifoliolate area for strawberry, Fragaria × ananassa Duch. ‘Redcoat’ and genotypes 62E55 and 71M59. Using regression analysis, the product of length and width (LW) was chosen as the independent variable. On the basis of predictive ability (R 2) and/or the SE of estimation, the following equations were chosen to determine leaflet area, lateral leaflet area, and trifoliolate area, respectively: A = 0.66LW + 0.89; A = 0.68LW; A = 0.69 ΣLW. A common regression equation could be used for the cultivar and genotypes studied. If the leaf is unequally imparipinnate, then the area of the lateral leaflets and the trifoliolate must be summed to obtain total leaf area.
A study examining the influence of trickle irrigation (TI), IRT-76 plastic film (PF) and straw mulch (SM) on the establishment of Rubus idaeus L. cv. `Heritage' micro-propagated raspberries was initiated at Cambridge, Ontario in 1993. Environmental, nutritional, vegetative and reproductive data were collected. Soil temperature and soil water status were greatly affected by TI, PF and SM. TI lowered soil NO3-N and increased soil NH4-N and Mg. PF increased soil NO3-N and NH4-N. Foliar N decreased by 10% with TI and increased by 8% with PF. Foliar P and Ca increased by 45 and 6% respectively, with TI. Node number was not influenced by TI, PF or SM. PF however, increased cane height, cane diameter, dry weight and leaf area by 14, 17, 77 and 11% respectively, and TI increased cane diameter by 13%. Although TI increased the number of fruiting laterals by 63%, there was no effect of TI, PF or SM on harvested berry number or weight.