David G. Himelrick

Cultivar Variation in Physicochemical and Antioxidant Activity of Alabama-Grown Blackberries

Abstract Blackberries are an excellent source of natural antioxidants. Fully ripened fruit of ‘Apache’, ‘Arapaho’, ‘Chester’, ‘Loch Ness’, ‘Navaho’ and ‘Triple Crown’ thornless blackberries were evaluated for their physicochemical and antioxidative activity. There were no consistent differences for variation in initial pH, titratable acidity (TA), total soluble sugar (TSS) and TSS/TA ratio values determined. Differences among cultivars with respect to reduced ascorbic acid (AA) were established, but there were no differences in either oxidized ascorbic acid (DHA) or total ascorbic acid (TAA) content. The antioxidant activity as determined by ABTS radical cation procedure for fractionated crude fruit extracts varied in response to parameters evaluated. Hydrophilic antioxidant activity (HAA) was not different among cultivars evaluated. In contrast, differences were found in lipophilic antioxidant activity (LAA) and total antioxidant activity (TAA).

Effect of Runner Plantlet Size on Performance of Strawberry Plug Plants

Abstract Size of plantlets used in propagation of strawberry plug plants did not affect yield or berry size. Daughter plants containing one to three compound leaves may be used in propagation. Plant size in this study was determined by petiole length to provide a simple grading method with easy application to the industry. Although no significant differences were identified among the three size classes evaluated in this “length based” study, plantlet size might affect eventual yields if sizes were determined by fresh weight or leaf area. Future studies in this area are warranted. Transplant survival should also be considered in future studies to determine whether particular sizes offer an advantage of lower mortality in the greenhouse, or if field survival is different among plants which differ in size at the initiation of propagation.

Handling, Storage and Postharvest Physiology of Muscadine Grapes

Abstract General principles pertaining to the regulation of temperature, relative humidity, and modified or controlled atmosphere conditions for maintaining the quality of fruits and vegetables during storage and transit can be applied to muscadine grapes. Muscadine grapes (Vitis rotundifoliaMichx.) are grown primarily in the southern United States and differ from other grape species and hybrids in that their berries are borne in small clusters of 3 to 10 berries and detach from their pedicels when ripe. In general high quality muscadines are free of injury, decay, and sunscald, appear and feel turgid, have a dry stem scar, and are fully bronze or black in color.

Fruit Quality and Antioxidant Properties in Alabama-Grown Blackberries During Fruit Maturation

Abstract Changes in fruit quality attributes and antioxidative properties from six cultivars of thornless blackberries (Rubus sp.) (‘Apache’, ‘Arapaho’, ‘Chester’, ‘Loch Ness’, ‘Navaho’, and ‘Triple Crown’) during four different ripening stages (red, motded, shiny-black, and dull-black) were determined under Alabama growing conditions. Berry fruit samples were evaluated for pH, titratable acidity, total soluble solids, TSS/TA ratio, soluble sugars, vitamin C (reduced, oxidized, and total) and antioxidant capacity (measured as trolox equivalent antioxidant capacity, TEAC). Significant variation among cultivars and maturity of harvest were in fruit quality attributes and antioxidative properties found. An increase in fruit pH concomitant with a decline in titratable acidity (TA) was observed during ripening for all cultivars. Total soluble solids (TSS) values increased from 5.7 to 11.6%, and TSS/TA ratio ranged from 11.9 to 63.6. Highest reducing and total sugar content were contained in dull-black fruit. Vitamin C content either declined or remained unchanged with ripening and the pattern was dependent on cultivar, maturity at harvest. In general, antioxidant activity declined between red and dull-black ripening stages. The results indicate that TSS/TA ratio and TEAC were good indicators of fruit maturity and nutritional quality, respectively.

Effect of Maturity at Harvest in Relation to Changes in Antioxidant Properties and Ethylene in ‘Chandler’ Strawberry Fruit

Abstract The relationship between fruit maturation and accumulation of hydrogen peroxide (H202), lipid peroxidation, ethylene (C2H4) production, antioxidant activity (hydrophilic, lipophilic and total) and the antioxidant enzyme ascorbate peroxidase (APX, EC 1.11.1.11) in fruit pericarp tissue of ‘Chandler’ (Fragaria xananassa Duch.) strawberry were measured. ‘Chandler’ fruit pericarp maturation and ripening were accompanied by a decline in H202 content early in fruit development followed by a rapid accumulation. An increase in membrane lipid peroxidation (thiobarbituric acid reactive substances, TBARS) coincided with accumulation of H202, which preceded a rise in C2H4 production. In general, antioxidant activity declined as fruit matured and ripened. APX enzyme activity increased by 2-fold and peaked at the pink stage of development and then gradually declined with ripening. H202 may serve as a signal molecule to initiate the cascade of oxidative processes during maturation and ripening. APX enzyme activity during maturation and ripening was not substantial and thus, may not have a role in alleviating accumulation of H202 and subsequent events related to oxidative senescence in fruit pericarp. To our knowledge, this is the first study to present fractionated antioxidant activities (HAA, LAA and TAA) from strawberry pericarp as assessed by the ABTS*+ radical cation assay. A fundamental understanding of the mechanisms involved in the senescent related-oxidative changes during strawberry fruit ontogeny in relation to quality and nutrition is discussed.

Effect of Temperature, Photoperiod and Pretreatment Growing Condition on Floral Induction in Springbearing Strawberry

Abstract ‘Chandler’ strawberry plants (Fragaria X ananassa Duch.) were greenhouse grown under natural lighting and then placed into growth chambers at two constant temperatures of 16 °C and 26 °C and two day lengths of 9 h (SD) and 9 h photoperiod (NI) which was night interrupted with 3 h of incandescent radiation at 30-45 μmol s ∼ 1m ∼ 2 PAR. Plants were given different numbers of inductive cycles in growth chambers and then moved to the greenhouse where flowering and growth were monitored. Flowering was completely inhibited at 26 °C, regardless of pretreatment growing conditions such as pot sizes and plant ages, photoperiod and inductive cycles. At 16 °C, SD promoted floral induction compared to NI under all inductive cycles except a 7-day induction. The minimum number of inductive cycles required at 16 °C for floral induction was dependent on photoperiod and prior greenhouse treatment. Flowering rate was also affected by greenhouse treatment, photoperiod and inductive cycles. Runner production was affected by photoperiod and temperature Xinductive cycle.

Effect of Primocane Topping Height and Lateral Length on Yield of ‘Navaho’ Blackberry

Abstract ‘Navaho’ erect thornless blackberry plants were subjected to a combination of three primocane summer topping heights and two lateral length pruning treatments. Plants were topped at 91, 122, 152 cm tall, and laterals were shortened to either 30 or 61 cm in length. Treatment effects on yield and plant structure were examined for four growing seasons. Lateral length had little effect on yield and any pruning height. Yield generally increased with increasing plant height. The 122-cm height appeared to optimize yield while still allowing for manageable floricane architecture.

Evaluation of Rose Hips (Rosa spp.) Selections

ABSTRACT An evaluation of the types of natural rose hip (Rosa spp.) populations was carried out in the Bursa region of Turkey where the rose hip has been traditionally grown intensively. Phenological development (first flowering, full flowering, fruit set, ripening), morphological characteristics (color of flower, number of leaflets, thornlessness), pomological qualities (fruit weight, fruit length and width, seed number, fruit flesh/seed ratio, fruit color) and chemical composition (soluble solids concentration, pH, total acidity, vitamin C, invert sugar, total sugar) were determined as evaluation parameters.

Use of Floating Row Covers in Annual Hill Plasticulture Strawberries

Abstract The response of strawberry plants in the annual hill plasti-culture system to the use of lightweight nonwoven rowcovers (17g/square meter) during the fall establishment period, winter and early spring was investigated. These fabrics can provide some cold and wind dessication protection and can also increase soil and air temperatures around the plant. The increased temperatures under the cover may simulate increased flower bud formation during the short day induction cycles in the fall and spring. Additionally, the covers may provide a protective environment where leaves remain functional for longer periods and crown and root development may be stimulated. In this study, row covers were installed and removed at various intervals from October through March. In addition to the uncovered control plants, the following row cover timings were imposed: Oct.-Mar., Oct.-Feb., Oct.- Dec., Oct.-Nov., Nov.-Mar., Oct.-Feb., Oct.-Jan., Oct.-Dec., Oct.-Nov., Nov.-Mar., Dec.-Mar., Jan.-Mar., and Feb.-Mar. Treatments were reduced from 8 to 6 in the last year of the study. The weight of marketable berries was affected by year and by treatment. Average performance for the four year period showed the Oct.-Feb. treatment to have the highest yields followed by Oct.-Nov. and Feb.-Mar. The Jan.-Mar. performed worse than the control in terms of both yield and berry size. Average berry weight was improved in the Oct.-Feb. and Oct.-Nov. treatment. Row covers in the best treatment (Oct.-Feb.) improved marketable yield by an average of 35% over the control.

Wild Berries in Finland

Abstract Finland abounds with wild berries. The annual harvest of wild berries in Finland has been estimated at more than 50 million kilograms (110 million lb)-more than ten kilograms (22 lb) per Finn. Approximately 50 different species can be found in Finland in all kinds of environments from rocky seashores to swamps and forests. Of all the different species of wild berries in Finland, roughly 20 are edible. The best known and most valuable are lingonberry, bilberry, cloudberry, and buckthorn berry. The most commonly traded of the wild berries is the lingonberry.