Location: Vegetable Crops Research2015 Annual Report
1a. Objectives (from AD-416):
Objective 1: Develop and apply genomic and genetic tools to map and characterize the genetic bases of the key cranberry traits that determine yield. Objective 2: Based on horticultural, genetic, and genomic information, formulate and apply breeding approaches for genetically improving cranberry yield. Objective 3: Determine the development thresholds of key arthropod pests (cranberry fruitworm and Sparganothis fruitworm) to better predict the developmental status of populations in the field. Objective 4: Develop novel, innovative IPM strategies to reduce pesticide use and sustain cranberry yield, quality, and profitability.
1b. Approach (from AD-416):
Objective 1: Next-generation sequencing technology will be used to characterize the cranberry genome. The resultant data will be used to discover and mine molecular markers such as SSRs and SNPs. We will then develop high-resolution genetic maps using the developed markers based on several available half-sib F1 mapping populations. Phenotyping will involve collecting data on yield-related traits and other horticultural measurements, including total fruit weight, percent rotten fruit, average berry weight, and fruit quality parameters. These traits will be localized in the linkage map described above. Information derived from the high resolution cranberry linkage map with yield-related will be used to plan strategic crosses. Objective 2: Prior to creating cranberry hybrids, horticultural, genetic, and genomic information will be carefully considered to ensure that strategic crosses are accomplished. A microsatellite marker based fingerprinting assay will be developed for the true-to-type verification of the cranberry cultivars. We will also characterize known cranberry diversity from the breeding programs and collections and samples sent in by growers. Pedigree information will be evaluated in the light of marker information to determine the most likely genotypes or genetic pools associated with each named cultivar and their associated horticultural performance. A series of cranberry hybrids with complementary genetic pools will be created and evaluated. Objective 3: The temperature-specific development rates and degree-day (DD) accumulations associated with cranberry fruitworm (CFW) and Sparganothis fruitworm (SFW) will be determined. Larval growth rates will be measured over a wide range of controlled temperatures. Growth rates will be plotted against temperature, and models will be fit to the dynamic. From these models, the lower and upper development thresholds will be isolated. The thresholds will then be used to generate degree-day (DD) accumulations that can be linked to discrete biological events, such as flight initiation in the field, adult lifespan, ovipositional period, and egg-hatch periods. DD accumulations represent key developmental benchmarks, helping to optimize pest management in the cranberry system. Objective 4: novel insect pest management approaches will be investigated. Two primary tactics will be explored within the cranberry system: pheromone-based mating disruption and trophic position measurement. In partnership with private industry, as well as Wisconsin cranberry growers, the first ever 3-species mating disruption program will be deployed at large scales within commercial marshes. Population suppression of the target pests will be assayed and compared with conventional pest management approaches. Studies of arthropod trophic position will be conducted using stable isotopic analysis of amino acids. Trophic position estimation will reveal the lifetime trophic tendencies of carnivorous species, thereby providing empirical evidence as to which species are actually beneficial for cranberry production.
3. Progress Report:
This progress relates to Objectives 1 and 2. We are developing molecular tools useful for breeding and genetics studies in cranberry using nuclear and organellear sequencing data from next-generation sequencing. Another area of emphasis has been the application of molecular tools to study the genetic diversity of cranberry germplasm. We are also generating critical applied and basic knowledge about cranberry traits, mainly yield and quality traits, to be integrated with current phenotypic selection methods and emerging molecular technology. A high density molecular map with information about traits of economic importance is also being developed that will help breed high yielding cranberry cultivars more efficiently. We currently have collected three years of cranberry phenotypic data on yield and other traits on two mapping populations. This progress relates to Objectives 3 and 4, and milestones 8-10. The ARS continues to advance the practice of integrated pest management (IPM) in United States cranberries by illuminating key elements of arthropod biology and ecology. Now in its fourth year of research and development, the multi-species pheromone-based mating disruption program in cranberries has been shown to be highly successful, reducing black-headed fireworm and cranberry fruitworm populations significantly. We are now scaling up the deployment of this technology to whole-marsh and regional applications using unmanned aerial vehicles (UAVs). To improve cranberry IPM programs, the development thresholds and degree-day benchmarks for cranberry fruitworm, Acrobasis vaccinii, are being pursued. This moth is the top pest of Wisconsin cranberries, thus effective control tactics are critical to crop protection objectives.
1. Polymorphic cranberry molecular markers. A lack of abundant, genome-wide molecular markers has limited the adoption of modern molecular assisted selection approaches in cranberry breeding programs. To increase the number of available markers in the species, ARS scientists in Madison, WI identified, tested, and validated microsatellite markers from existing deoxyribonucleic acid (DNA) sequencing data. In total, 979 DNA markers were designed, synthesized, and tested; 697 of the markers were found to be variable in four cranberry plants. Of the 697 variable markers, 507 were selected for additional genetic diversity and segregation analyses in 29 cranberry plants. More than 95% of the 507 markers did not display segregation distortion and contained moderate to high levels of diversity. This comprehensive collection of developed and validated DNA markers represents a substantial addition to the molecular tools available for geneticists and genomicists in cranberry and Vaccinium that will allow breeders to development of new molecular breeding schemes to produce improved varieties for growers and consumers.
2. Wild diversity in cranberry. The natural populations of American cranberry (Vaccinium. macrocarpon) and small cranberry (V. oxycoccos) were characterized by ARS scientists from Madison, WI, using microsatellite markers. The data collected offers insight into natural cranberry diversity and differentiation among two closely related species and will be useful for future studies about natural cranberry diversity and natural population characteristics as well as other cranberry breeding and genetics studies. Unique cranberry types can be generated by the hybridization of V. macrocarpon and V. oxycoccos populations. Therefore, a genetic fingerprint allowing the differentiation of each species will aid further studies of genetic diversity and pedigree analysis of natural and breeding populations.
3. Cranberry iron nutrition. Cranberry is naturally adapted to environments with high concentrations of soluble iron. Yet, there is a need to further explore iron nutrition in cranberry given concerns of toxicity problems from irrigation with iron-rich water. ARS scientists from Madison, WI, investigated the threat of iron toxicity by evaluating chelated iron effects on cranberry plant growth. Shoot growth was reduced with increasing chelated iron concentrations and plant symptoms included leaf drop, necrosis, mortality in the higher concentration treatments, and increasing amounts of iron with increasing chelated iron dosages. However, iron tissue levels were within the normal range found in healthy field plants in all treatments. We hypothesized that the toxicity symptoms observed in cranberry plants treated with chelated iron is likely due to a specific toxicity of cranberry to the chelators not the iron. Elucidating the benefits or risks to particular accumulations of iron and other micronutrients are needed in order to establish sufficiency ranges, thresholds, and help growers better understand toxicity risks.
4. Cranberry yield studies. Improved methods of yield prediction are essential to develop early crop pricing forecasts for the cranberry industry. However, yield is a complex trait that is influenced by multiple interacting factors involving crop genetics, plant physiology, and the environment. The fact that each factor is poorly understood and the interaction between factors complicate yield prediction. ARS scientists from Madison, WI, improved the current understanding of yield by measuring the effects of genetic, physiological, and environmental variables on yield. Sixty-six variables representing several commercial cultivars were studied for two years. Yield in cranberry was strongly influenced by fruit number and size. However, fruit traits are not as useful for early prediction of yield. Although early crop forecasting in cranberry may be difficult, this study suggests that managing environmental and genetic variability while maintaining consistency in yield may be crucial in the development of more accurate methods of yield prediction.
5. Physiology and seasonality of cranberry arthropod pests. Insects are consistently ranked as the top pest threats to Wisconsin cranberry production. To improve insect management efforts, ARS researchers in Madison, WI, measured larval growth rates of a major pest, the Sparganothis fruitworm, as a function of temperature. Then, growth rates were modeled across a broad temperature range to isolate the temperature thresholds demarcating maximal and minimal growth. Finally, growth thresholds were used to generate degree-day accumulations based on local weather data, and these accumulations were linked with discrete biological events (“degree-day benchmarks”) in the insect’s life cycle, so that growers can better estimate optimal spray timings using their local weather reports.
6. High-resolution food web studies. In collaboration with researchers in Yokosuka, Japan, the University of Wisconsin, and the University of New Mexico, ARS researchers in Madison, WI, have examined food-chains in both natural and managed ecosystems (farms). This study represents the largest assessment of consumer trophic position (i.e., place in the food-chain), using amino acid isotopic analysis. We provide the first definitive evidence that omnivory is the dominant paradigm of food web ecology. This means that many populations in agricultural fields are not neatly compartmentalized into functional “roles,” but rather indulge in a high degree of trophic opportunism, that often involves cannibalism and/or attacking beneficial insects, which undermines crop protection objectives. A nationwide conversation on the establishment of IsoBank, an indexed, searchable archive for isotopic data, modeled after GenBank have been started. These kinds of archives further the advancement of science by facilitating massive data sharing and providing bases for biological pest management programs.
7. Pollinator health in cranberries. Fungicides are often sprayed on flowering cranberry beds, sometimes 2-3 times during bloom. Given that cranberries are a native plant, native pollinator species (180+ species) commonly visit commercial marshes, resulting in exposure to fungicides. University of Wisconsin and ARS researchers in Madison, WI, examined how colonies of a native bumble bee species, Bombus impatiens, performed following exposure to fungicide residues. We report the first evidence that fungicides, once widely considered “bee-safe,” may be detrimental to native bee health. This establishes a basis to re-examine the wisdom of applying fungicides to flowering crops, whether pollinated by managed or wild bees.
Deutsch, A.E., Rodriguez-Saona, C.R., Zalapa, J.E., Steffan, S.A. 2015. Temperature-mediated development thresholds of Sparganothis sulfureana (Lepidoptera: Tortricidae) in cranberries. Environmental Entomology. 44(2):400-405.
Zalapa, J.E., Bougie, T.C., Bougie, T.A., Schlautman, B.J., Wiesman, E., Guzman, A., Fajardo, D.A., Steffan, S., Smith, T. 2014. Clonal diversity and genetic differentiation revealed by SSR markers in wild Vaccinium macrocarpon and Vaccinium oxycoccos. Annals of Applied Biology. 166(2):196-207.
Deutsch, A.E., Rodriguez-Saona, C.R, Kyryczenko-Roth, V., Sojka, J., Zalapa, J.E., Steffan, S.A. 2014. Degree-day benchmarks for Sparganothis sulfureana (Lepidoptera: Tortricidae) development in cranberries. Journal of Economic Entomology. 107(6):2130-2136.
Chikaraishi, Y., Steffan, S.A., Ogawa, N.O., Ishikawa, N.F., Sasaki, Y., Tsuchiya, M., Ohkouchi, N. 2014. High-resolution food webs based on nitrogen isotopic composition of amino acids. Ecology and Evolution. 4(12):2423-2449.
DeVetter, L., Colquhoun, J., Zalapa, J., Harbut, R. 2015. Yield estimation in commercial cranberry systems using physiological, environmental, and genetic variables. Scientia Horticulturae. 190(1):83-93.
Schlautman, B., Fajardo, D., Bougie, T., Wiesman, E., Polashock, J., Vorsa, N., Steffan, S., Zalapa, J. 2015. Development and validation of 697 novel polymorphic genomic and EST-SSR Markers in the American cranberry (Vaccinium macrocarpon Ait.). Molecules. 20(2):2001-2013.
Jones, V.P., Horton, D.R., Mills, N.J., Unruh, T.R., Baker, C.C., Melton, T.D., Miliczky, E., Steffan, S.A., Shearer, P.W., Amarasekare, K.G. 2015. Evaluating plant volatiles for monitoring natural enemies in apple, pear and walnut orchards. Biological Control. 102:53-65. doi: 10.1016/j.biocontrol.2015.03.009.
Pauli, J.N., Steffan, S.A., Newsome, S.D. 2015. It is time for IsoBank. Bioscience. 65(3):229-230.
Chikaraishi, Y., Steffan, S.A., Takano, Y., Ohkouchi, N. 2015. Diet quality influences isotopic discrimination among amino acids in an aquatic vertebrate. Ecology and Evolution. 5(10):2048-2059.
Bernauer, O.M., Gaines-Day, H.R., Steffan, S.A. 2015. Colonies of bumble bees (Bombus impatiens) produce fewer workers, less bee biomass, and have smaller mother queens following fungicide exposure. Insects. 6(2):478-488.
Siebach, S., Zalapa, J., Covarrubias-Pazaran, G., Harbut, R., Workmaster, B., Wasko DeVetter, L., Steffan, S., Guedot, C., Atucha, A. 2015. Toxicity of chelated iron (Fe-DTPA) in American cranberry. Journal of Horticulture. 2:129. DOI:10.4172/2376-0354.1000128.