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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.
Abstract
Shoot growth of highbush blueberry (Vaccinium corymbosum L. cv. Bluecrop) in vitro was compared on various modifications of Murashige and Skoog (MS) medium containing Linsmaier and Skoog (LS) vitamins, Zimmerman’s Z-2 and Z-3 media, a modified Knop’s medium, and McCown and Lloyd’s woody plant medium (WPM). The WPM was found to produce best growth and highest number of shoots of 10 mm or longer. Shoots from Zimmerman’s half-strength medium (Z-3) yielded the highest percentage of rooting in sifted sphagnum peat.
Abstract
Two mist systems, one in a mature orchard and the other in a young hedgerow, delayed bloom 15 days for ‘Bartlett’ and 8 days for ‘Bosc’ pear (Pyrus communis L.), while a low pressure sprinkler system delayed bloom for 14 days for ‘Bartlett’ and 8 days for ‘Bosc’ in 1976. Bloom delay generally increased fruit set and seed content of the fruit. Return bloom was greatly reduced in the mature orchard ‘Bartlett’ mist and ‘Bosc’ sprinkler plots in 1976 and, in turn, cropping was reduced the following year on these plots. Yield during treatment years was generally lower in the delayed areas. Fruit growth rates were accelerated in the bloom-delayed trees, but total fruit volume was less than the non-delayed fruit. Leaf nitrogen levels were reduced in all bud delayed treatments. Pear psylla oviposition was delayed in the mist system. Fire blight, caused by Erwinia amylovora (Burr.) Winslow et al., absent in 1975, was found in the misted ‘Bosc’ and in the sprinkled plots of both cultivars in 1976.
Abstract
Mature orchard misting and sprinkling and young hedgerow misting for bloom delay of pear (Pyrus communis L.) reduced fruit sizes of ‘Bartlett’ 6% and of ‘Bosc’ 12%. Harvest maturity, indicated by fruit pressure testing, was delayed 0 to 6 days for ‘Bartlett’ and 2 to 7 days for ‘Bosc’. The effect of bloom delay on fruit size and maturity was greater on ‘Bosc’ than ‘Bartlett’. Bloom delay had a greater effect on fruit sizing at harvest (3.5 days for every 6 days of bloom delay) than on harvest maturity (1 day for every 6 days delay). Soluble solids, not affected in pears from the mature plots, were slightly lower in the misted hedgerow. Titratable acids were not influenced by bloom delay.
Floating treatment wetlands (FTWs), a modified constructed wetland technology, can be deployed in ponds for the treatment of nursery and greenhouse irrigation runoff. The pH of nursery and greenhouse operation irrigation water varies from 3.3 to 10.4 across the United States. Water flow rate, plant species selection, and variable nutrient inputs influence the remediation efficacy of FTWs and may interact with the pH of inflow water to change nutrient remediation dynamics. Therefore, an experiment was designed to quantify the effect of pH on the growth and nutrient uptake capacity of three macrophyte species using a mesocosm FTW system. ‘Rising Sun’ japanese iris (Iris ensata), bushy bluestem (Andropogon glomeratus), and maidencane (Panicum hemitomon) were grown for two 6-week periods and exposed to five pH treatment levels representing the range of nursery and greenhouse irrigation runoff, 4.5, 5.5, 6.5, 7.2, and 8.5, for a total of 15 plant and pH combinations. Water was treated with either hydrochloric acid to decrease the pH or sodium hydroxide to increase the pH. The pH-adjusted solutions were mixed with 12 mg·L−1 nitrogen (N) and 6 mg·L−1 phosphorus (P) fertilizer (64.8 g·m−3 N and 32.4 g·m−3 P). Differences in pH impacted both N and P removal from the FTW systems for two of the three species studied, maidencane and bushy bluestem. Higher pH treatments reduced nutrient removal efficacy, but plants were still capable of consistently removing nutrients across all pH treatments. Conversely, ‘Rising Sun’ japanese iris maintained similar remediation efficacies and removal rates across all pH treatments for both N and P, possibly due to the ability to acidify its rhizosphere and modify the pH of the system. Average N and P loads were reduced by 47.3 g·m−3 N (70%) and 16.6 g·m−3 P (56%). ‘Rising Sun’ japanese iris is a promising plant for use in highly variable conditions when the pH of irrigation runoff is outside the typical range (5.5–7.5). Results from model simulations poorly predict the nutrient availability of P and ammonium in effluent, most likely due to the inability to determine plant and biological contributions to the system, such as N-fixing bacteria.