certain pest control products, as well as climate change ( Vorsa and Johnson-Cicalese, 2012 ). Development of new cranberry cultivars exhibiting the fruit-quality standards demanded by the SDC industry, while overcoming other production challenges, will
R. Karina Gallardo, Parichat Klingthong, Qi Zhang, James Polashock, Amaya Atucha, Juan Zalapa, Cesar Rodriguez-Saona, Nicholi Vorsa and Massimo Iorizzo
Lisa Wasko DeVetter, Rebecca Harbut and Jed Colquhoun
as a result of bed renovation decisions made by the grower. Table 1. Cranberry cultivars included in the study, their respective dates of release, parentage, and geographical origin. Plant growth and yield data were collected from three randomly
Betsey Miller, Denny J. Bruck and Vaughn Walton
damage on actual yield or translocation of water and nutrients from the roots to the plant canopy is yet to be determined. Cranberry producers in the PNW should consider BVW tolerance when selecting cultivars for new plantings and more cranberry cultivars
Carolyn J. De Moranville*
Cranberry fruit development was studied in 3 years at the Univ. of Massachusetts Cranberry Station farm. Beginning at 4 weeks from 50% out of bloom and continuing until late Sept, 5 replicate samples of 25 fruiting uprights were collected biweekly from each of 7 cultivar beds. Fruit were removed from uprights and sorted into size classes using stacked soil sieves (16-, 12.5-, 9.5-, and 5.6-mm grids). Fruit from each class was counted and weighed. `Ben Lear', a native Wisconsin selection and the fourth most planted cultivar in Massachusetts, consistently produced the greatest yield (mass) of fruit. This was attributed to consistent fruit retention and large fruit size (majority of fruit at harvest were >12.5 mm in dia). In comparison, `Pilgrim', a large-fruited hybrid cultivar, was near the median for fruit yield due to poor fruit set (≈1.2 berries per upright compared to ≈1.6 for `Ben Lear'). `Stevens', the hybrid cultivar of choice in the MA cranberry industry, had yield similar to `Ben Lear' in only 2 of 3 years. Fruit set and retention in `Stevens' was less than that in `Ben Lear', but larger mass of individual fruit in `Stevens' generally made up for fewer fruit produced. Native cultivars `Early Black' and `Howes', which account for >50% of the MA cranberry acreage, had variable yield attributable to variable fruit set and retention by year. These cultivars bear small fruit (≈1 gm/berry; only half of berries >12.5 mm in diameter). Growth curves showed evidence of a `lag phase' in cranberry fruit mass accumulation occurring approximately at the mid-point of fruit development. Although much of the final fruit mass had accumulated by Sept, additional mass did accumulate up to the harvest of the beds (≈1Oct.). This has implications for growers who harvest fruit in early Sept for `white' cranberry juice.
Carolyn J. DeMoranville, Joan R. Davenport, Kim Patten, Teryl R. Roper, Bernadine C. Strik, Nicholi Vorsa and Arthur P. Poole
Fruit mass development in `Crowley', `Pilgrim', and `Stevens' cranberry (Vaccinium macrocarpon Ait.) was compared in five states for two seasons. Comparing all locations, `Stevens' and `Pilgrim' cranberries had similar growth curves with a faster growth rate than that of `Crowley'. Regional differences in fruit development were observed. Shorter growing seasons, especially in Wisconsin, were compensated for by more rapid growth rates. Conversely, low initial mass and slower growth rates were compensated for by the longer growing season in the Pacific Northwest. Solar radiation intensity accounted for little of the variability in fruit growth. Neither growing degree days nor numbers of days were good predictors of cranberry fruit fresh mass accumulation. Instead, numbers of moderate temperature days (between 16 and 30 °C) appeared to be key, accounting for greater than 80% of the variability in cranberry fresh biomass accumulation. The most rapid growth rates occurred when temperatures were in this range. High temperatures were limiting in New Jersey while low temperatures were limiting in Oregon and Washington. In one of two seasons, low temperatures were limiting in Wisconsin: accumulation of 0.5 g fresh mass took 11 d longer. Massachusetts had the fewest periods of temperature extremes in both seasons, resulting in the shortest number of days required to accumulate 0.5 g fresh mass.
Justine E. Vanden Heuvel and Carolyn J. DeMoranville
1800s and has historically been based on two wild selections from native cranberry stands, ‘Early Black’ and ‘Howes’. ‘Early Black’ is the predominant cranberry cultivar in Massachusetts ( DeMoranville, 2004 ). The fruit of ‘Early Black’ are dark in
Richard G. Novy and Nicholi Vorsa
Cranberry (Vaccinium macrocarpon Ait.) has few qualitative, morphological characteristics that can be used to reliably distinguish among cultivars. Fifty-two silver-stained random amplified polymorphic DNAs (ssRAPDs) were used to assess genetic heterogeneity and relatedness within accessions of four major cranberry cultivars (`Early Black', `Howes', `McFarlin', and `Searles'). Rather than being represented by one genotype, as might be expected in an asexually propagated crop, each cultivar was represented by multiple genotypes, which in many cases did not appear to be closely related to one another. The intracultivar heterogeneity was often so extreme that clonal representatives of a cultivar would group with representatives of other cultivars following cluster analysis. Of the total ssRAPD variation, 9.7% could be attributed to variation among the four cultivar groups and 90.3% to variation within the cultivars. `Howes' was the only cultivar in which a consensus DNA fingerprint among regional representatives could be identified.
Teryl R. Roper and Marianna Hagidimitriou
Carbohydrate concentration may be important for flower initiation and fruit set in cranberry (Vaccinium macrocarpon Ait.). Fruit set has been shown to be a major limiting factor in yield component analysis. The objective of this research was to identify carbohydrate concentrations in cranberry tissues at various stages of development under field conditions. Samples of two cranberry cultivars, `Stevens' and `Searles' were collected during the 1989 season using a 13 cm diameter probe. Samples were divided into fruit, uprights, woody stems and roots. Carbohydrates were quantified by HPLC. Nonstructural carbohydrates were primarily sucrose, glucose, fructose and starch. Soluble carbohydrate concentration was stable throughout the season in tissues analyzed, while starch content was high early in the season then decreased during blossom and fruit set. This work shows that starch reserves in leaves and stems apparently are remobilized to support fruit set in cranberry.
Dana L. Baumann, Beth Ann Workmaster and Kevin R. Kosola
Wisconsin cranberry growers report that fruit production by the cranberry cultivar `Ben Lear' (Vaccinium macrocarpon Ait.) is low in beds with poor drainage, while the cultivar `Stevens' is less sensitive to these conditions. We hypothesized that `Ben Lear' and `Stevens' would differ in their root growth and mortality response to variation in soil water potential. Rooted cuttings of each cultivar were grown in a green-house in sand-filled pots with three different soil water potentials which were regulated by a hanging water column below a fritted ceramic plate. A minirhizotron camera was used to record root growth and mortality weekly for five weeks. Root mortality was negligible (2% to 6%). Whole plant relative growth rates were greatest for both cultivars under the wettest conditions. Rooting depth was shallowest under the wettest conditions. Whole-plant relative growth rates of `Ben Lear' were higher than `Stevens' at all soil water potentials. `Stevens' plants had significantly higher root to shoot ratios and lower leaf area ratios than `Ben Lear' plants, and produced more total root length than `Ben Lear' at all soil water potentials. Shallow rooting, high leaf area ratio, and low allocation to root production by `Ben Lear' plants may lead to greater susceptibility to drought stress than `Stevens' plants in poorly drained cranberry beds.
Ricardo Cesped-Ruiz* and Bingru Huang
The American cranberry often undergoes drought stress during the summer. However, the physiological response of this species to drought is not well understood. This study was designed to determine the effects of drought on two commercial cranberry cultivars of high potential yield, `Ben Lear' and `Stevens', during a vegetative stage. The plants were subjected to drought for 15 days in a greenhouse. Soil water content, leaf water content, leaf photosynthetic rate, stomatal conductance, transpiration, differential leaf-air temperature, photochemical efficiency (Fv'/Fm') and the actual PSII efficiency (deltaF/Fm') decreased in those plants subjected to drought. Drought reduced differential leaf-air temperature at day 6 of treatment and stomatal conductance and transpiration starting at day 9 and photosynthetic rate at day 13. Drought decreased leaf water content at day 14 and Fv'/Fm' and PSII efficiency at day 15. Our results indicated that cranberry plants in vegetative stage were sensitive to drought for both cultivars and stomatal conductance was the most sensitive parameter among those examined for both cultivars.