Abstract
‘Tifblue’ rabbiteye blueberry (Vaccinium ashei Reade) yields were greatest when expressed as kg of fruit per bush; however, ‘Woodard’ outyielded ‘Tifblue’ and ‘Bluegem’ per m3 of canopy volume. ‘Tifblue’ was subjected to the greatest daytime water stress due to its large canopy volume and limited feeder root density. Consequently, changes in feeder root density had a pronounced effect on yields in ‘Tifblue’. Yield was also affected to a lesser extent by feeder root density in ‘Bluegem’ but was independent of this factor in ‘Woodard’.
Infestations of Botrytis blossom blight (Botrytis cinerea) can reduce yields in commercial blueberry fields in the Pacific Northwest. In 1993, environmental conditions during blueberry flowering were ideal for the development of Botrytis. Individual plants were evaluated in a replicated highbush blueberry culture/advanced selection trial (42 clones, 5 reps, 3 plants) in Aurora, Ore. Each plant was evaluated for damage due to Botrytis using a subjective scoring system (1= all flower clusters on plant appear blighted, 5= many blossoms blighted, 9= no blossoms blighted). Many clones showed very little injury. The following clones showed the greatest injury, in decreasing order of severity, NC 2678, `Bluechip', `Bounty', G-805, `Nelson', G-224, `Berkeley', `Sierra', and `Bluegold'. In addition, Botrytis damage was scored on the field collection of Vaccinium at the National Clonal Germplasm Repository. Data from this nonreplicated study will also be presented.
Abstract
Respiration is of primary importance to the plant since it liberates energy to do chemical work in synthesizing energy-rich materials involved in growth. Although the respiratory rate of many plant tissues and organs have been studied (1), no data on respiratory rate of blueberry leaves was found in a search of the literature. It is felt that data on the respiratory rate of highbush blueberry (Vaccinium corymbosum L.) would be of value since it will provide basic information for comparison with other genera.
Abstract
Budbreak of ‘Woodard’ and ‘Bluegem’ rabbiteye blueberry (Vaccinium ashei Reade) occurred sooner than ‘Tifblue’ following chilling at constant 10 and 15°C and a diurnal regime of 8 hours at 15°/16 hours at 7°. Results indicate a narrower range of effective chilling temperatures for ‘Tifblue’. The temperature effect was more pronounced for ‘Woodard’ rooted cuttings than budsticks and was more significant for floral than vegetative budbreak. Floral budbreak of rooted cuttings subjected to 14 days at 30° in the middle of the chilling period was faster than at continuous chilling treatments. The number of days required for budbreak was significantly reduced as chilling hours increased.
Blueberry fruit were harvested at commercial maturity from variety trials and shipped overnight to UC Davis. Fruit quality was evaluated upon receipt and after 6 and 20 days of cold storage at 0.5 °C in air shelf life. Firmness, external color, soluble solids, and titratable acidity were measured. Sensory evaluations were conducted by trained tasters to rate the blueberries for crispness, mealiness, sweetness, tartness, blueberry flavor, and off-flavors at harvest and again after 21 days of storage. Many of the blueberries increased in firmness during cold storage. Firmness at harvest tended to be softer in `Santa Fe' and `Jewel' and firmer in `Star'. Sensory data also found `Sharpblue' and `Southmoon' to be more firm; however the objective measurements did not agree. Overall, `Saphire' was low in sugars and acids, and `Jewell' and `Star' were high in acids. `Misty' and `Sharpblue' were consistently high in sugars and acids. Overall objective fruit quality ratings were highest for `Misty', `Sharpblue', and `Southmoon', and lowest for `Santa Fe'. Blueberry flavor was rated highest in `Jewell', `Star', and `Sharpblue', and lowest in `Santa Fe', `Saphire', `Misty', and `Emerald'. These data indicate that blueberry flavor may be closely tied to acid content, as most of the high-flavor varieties had high acid and many of the low-flavor varieties had low acid. Over 3 years, the varieties consistently rated highest for overall objective quality were `Misty' and `Southmoon'. `Star' was rated high for overall quality in 2 years and moderate in 1. `Jewell', `Star', and `Sharpblue' were rated highest in flavor. `Santa Fe' was ranked low in flavor quality in 2 out of 3 years. Selection of variety appears to have a strong influence on the sensory quality of the blueberries marketed.
exceptions, are exclusively hand harvested if destined for fresh market ( Strik and Yarborough, 2005 ). In southern Georgia, southern highbush blueberry cultivars ripen in late April and early May. Rabbiteye blueberries (≈12,000 acres), in contrast, are often
hybridization reached its height during the development of “southern” highbush blueberry cultivars, which began in 1948 at the University of Florida ( Sharpe, 1953 ). Southern highbush blueberries (SHB) are low-chill (less than 600 h below 7 °C) interspecific
. Table 1. Mummy blight estimates, ranks, and raw percentages compared with blueberry cultivar standards (bold) listed in order of increasing susceptibility. Fruit infection screening materials. Six cultivars were selected as standards
effect of fertilizer rate and composition on growth and yield of two SHB blueberry cultivars grown in a containerized pine bark production system. Materials and Methods One-year-old ‘Misty’ and ‘Star’ SHB nursery plants were obtained from a north
programs have developed blueberry cultivars that grow in a wider array of climates, allowing production to flourish in South America, Europe, Asia, and Australia. Global highbush blueberry production passed the one billion pound mark in 2012 and continues