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Polyethylene glycol (PEG) was evaluated for its influence on hardening of in vitro-propagated `Fern' strawberries (Fragaria ×ananassa) when applied just before transplanting. Strawberries were micropropagated via shoot tips and grown in vitro until roots were well developed. Plantlets were then transferred onto filter paper bridges in liquid medium with 15% (w/v) of PEG-8000. After treatment in the medium for various periods, the plants were compared to the control (no PEG) for water loss from detached leaves, stomatal aperture, and survival rates after transplanting. Leaf epicuticular wax was also quantified. Overall, the in vitro PEG treatment was not successful in significantly increasing hardiness and survivability of the strawberry plants after transplanting from in vitro conditions to a soil medium. Osmotic stress was created, but apparently not for the time needed to increase survival. Further tests are needed to pinpoint the proper exposure time required to increase hardiness and survivability after transplanting plantlets. To increase survival, the time exposed to PEG should be 15, 18, or possibly 21 days.
Abstract
Grape breeding was initiated by the Arkansas Agricultural Experiment Station in 1964. The major objective of this program has been to develop high quality table grapes adapted to the soils and climate of Arkansas. ‘Venus’, a blue seedless table grape, is the first cultivar released from this program.
A computerized relational database is an efficient and powerful way to store, retrieve, query, and manipulate data. Databases have been prevalent in the scientific community for several years but, recently, have become more immediately available. Personal computers and local area networks (LAN) have revolutionized the accessibility of shared data. At the USDA-ARS Sugarcane Field Station, a database has been created to streamline the entry and recovery of data for the breeding program using Microsoft (MS) Access 2000, a readily available and inexpensive product, which makes it highly adaptable to a variety of breeding programs. Data collection from the sugarcane breeding program has previously consisted of field books and separate computer files. This method of documentation can lead to errors and lost data, therefore a multi-user database was needed to avoid continued problems in data handling. Data entry is performed though a series of self-explanatory forms. Once entered, data can be accessed through the LAN and easily sorted or grouped as desired or queried for items of interest. Reports can then be output as a means of storing important hard copy records. Data from stage I and stage II (the first two clonally propagated selection stages) of the breeding program have currently been included in the database, as well as the seedling stage (true seed planting). Future plans are to incorporate data from stage III and IV (the final two clonally propagated selection stages). The database also handles the Canal Point breeding collection inventory, crossing information, seed (fuzz) inventory, and pedigree tracking. This type of database has widely applicable properties that can be implemented to handle data for any crop, either agronomic or horticultural.
Abstract
The cultivars ‘Earlidawn’, ‘Earlibelle’, ‘Sunrise’, ‘Midland’, ‘Florida 90’, ‘Surecrop’, and the selections ‘Md-US 2713’, ‘Md-US 3107’, ‘Md-US 2819’, and ‘Md-US 2593’ exhibited the greatest concentration of fruit maturity of 26 cultivars and selections evaluated. ‘Sunrise’ was outstanding in both concentration of ripening and total yield. Both total yields and acceptable yields were greatly reduced by single harvests in comparison with a multiple-harvested control. Highest yields of acceptable fruit from single harvests were obtained when the harvest was made during the second week of the ripening season, although average size of acceptable fruit was larger when the harvest was made earlier in the season.
Abstract
Iron chlorosis often develops in blueberries (Vaccinium) grown on soils with a pH above 5.2. Seedlings of 4 blueberry intra- and interspecific progenies, involving V. ashei, V. corymbosum, and V. darrowii, were tested for Fe-efficiency (use of Fe) by growing them in nutrient solutions containing different concentrations of CaCO3 to vary the pH. Plants received Fe during the first 4 harvests (up to 75 days) but received no Fe during the subsequent 2 harvests. The Fe supply for plant growth in the last 2 harvests was limited to that available in the roots. T-65 × US 67 blueberry plants [a 3-species hybrid of V. ashei × (V.darrowii × V. corymbosum)] lowered the pH of the nutrient solution by releasing H+ from their roots which freed Fe from root accumulations and made it available for plant use. ‘Climax’ × T-151 (V. ashei × V. ashei) progeny did not do this. Seedlings of V. corymbosum and those from a cross of V. corymbosum with V. darrowii were intermediate in their response.
Four sterilants-bactericides (Physan-20, Fixed Copper, Phyton-27, and Virkon) were compared as preplanting dips of Zantedeschia elliottiana Engl. W. Wats `Yellow' (a susceptible cultivar) rhizomes to reduce plant losses due to latent field-infected Erwinia carotovora soft rot during greenhouse forcing as a flowering potted plant. All sterilant solutions were prepared in combination with Promalin, a commercially available product containing gibberellic acid (GA) used to enhance flowering. An additional group of rhizomes was inoculated with E. carotovora sp. as a preplanting dip in combination with the GA treatment but were not treated with a bactericide. Rhizomes were wounded by making two cuts on the distal part of the rhizome or left unwounded before application of the preplant dip treatments. After potting, plants were fertilized with either a high (3.0 mmol·L-1) or a low (1.0 mmol·L-1) calcium nutrient solution through subirrigation. More than 90% of the inoculated rhizomes collapsed within 5 weeks after potting due to bacterial soft rot. With the uninoculated rhizomes, the copper-based compounds (Fixed Copper or Phyton-27) provided better control of bacterial soft rot than either Physan-20 or Virkon only during the first 6 weeks of forcing. During the remainder of the forcing period, there were no differences in weekly losses of rhizomes with the four sterilants. Confirmation of Erwinia carotovora subsp. carotovora (Jones) Bergey et al. as the causal organism was made throughout the experiment. Incisions on the rhizome before planting or calcium nutrition during forcing did not have any significant effect on disease severity. Rhizomes treated with solutions of the copper-based compounds produced 0.5 flowers less per rhizome than either Physan-20 or Virkon. High calcium fertilization resulted in an increase of 0.5 flowers per plant compared to low calcium nutrition.
The effect of various mulch colors (black, yellow, red, blue, white, and aluminum) on growth and development of `Vates' collards was evaluated in Fall 1996 at the E.V. Smith Research Center in Shorter, Ala. Black polyethylene mulch was installed onto raised, fumigated beds, then sprayed with a 1: 2 (v/v) mixture of exterior oil-based enamel paint to paint thinner with one of the five mulch colors listed. Five-week-old plants were transplanted into beds. Beginning two weeks after transplanting and continuing every other week thereafter, heads were harvested to determine head fresh weight and dry weight. Hourly soil temperatures at 10 cm soil depth were recorded and growing degree days (GDDs) with a base temperature of 4.4 °C were calculated. At two weeks after transplanting, average head fresh and dry weight were highest for the aluminum-colored treatment with head fresh (24.7 and 12.3 g, respectively) and dry weights (2.7 and 1.3 g, respectively) twice that of the yellow treatment (P ≤ 0.05). By four weeks after transplanting and up through the final harvest, marketable yield and average head fresh weights did not differ among the treatments (17,900 kg/ha, 1.4 kg per head, respectively). The red and black mulch treatments accumulated more GDDs than the other treatments, but total marketable yields did not differ among any treatments.
Abstract
The relative decline in fruit size from primary to secondary to tertiary positions on the inflorescence of large-fruited clones was much greater than for small-fruited clones. Large-fruited clones produced fruit with more achenes and larger achenes than did small-fruited clones. Fruit weight was positively correlated with total achenes per fruit, developed achenes per fruit, mean weight of total and developed achenes, and fruit weight per developed achene. These results lead to the conclusion that fruit size differences among strawberry clones are due to the combined effects of developed achene number, developed achene size, differential activity of achenes in producing growth hormones and differential sensitivity of receptacular tissue in responding to growth hormones.
Kentucky is one of seven states in the southeast evaluating 13 Asian pear cultivars for suitability to the region. The cultivars were planted on a (20′ × 10′) spacing in 1989 at three separate locations. Data on time of bloom, tree growth, fire blight susceptibility and fruit quality and yield were collected. This study demonstrates the variability seen in Asian pear cultivars in response to site. There was a significant site by cultivar interaction for fire blight. The Princeton site had significantly more fire blight than either Lexington or Quicksand. Four cultivars, Niitaka, Shin Li, Shinko and Shinseiki had low fire blight ratings which were not significantly different between the three sites. Asian pear growth rates were significantly different between the three sites, but cultivar growth rates were not. Tree growth rate showed a significant negative correlation to fire blight rating. That is infected trees did not grow much. Initial findings show Shinko, Shinseiki and Niitaka to have some tolerance to fire blight spread and to produce good yields of attractive fruit. However, Niitaka had a very tough skin with a tendency towards fruit cracking. The cultivar Shin Li which also had fire blight tolerance did not produce fruit or flowers.