Nineteen peach [Prunus persica (L.) Batsch] genotypes and 45 plum (Prunus salicina Erhr. and hybrids) genotypes with different flesh and skin color were analyzed for their antioxidant content and activity. Anthocyanin content, phenolic content, and antioxidant activity were higher in red-flesh than in light-colored flesh peaches. Carotenoid content was higher in yellow-flesh peaches than in light-colored ones. Red-flesh plums generally had higher anthocyanin and phenolic contents than the other plums but not necessarily greater antioxidant capacity. The total phenolic content had the most consistent and highest correlation with antioxidant activity, indicating that it is more important in determining the antioxidant activity of peaches and plums than are the anthocyanin or carotenoid contents. In general, the wide range of phytochemical content and antioxidant activity found indicates that the genetic variability present can be used to develop cultivars with enhanced health benefits.
Marcia Vizzotto, Luis Cisneros-Zevallos, David H. Byrne, David W. Ramming, and W.R. Okie
Unaroj Boonprakob, David H. Byrne, Charles J. Graham, W.R. Okie, Thomas Beckman, and Brian R. Smith
Diploid plums (Prunus L. sp.) and their progenitor species were characterized for randomly amplified polymorphic DNA polymorphisms. Bootstrap analysis indicated the variance of genetic similarities differed little when the sample size was >80 markers. Two species from China (Prunus salicina Lindl. and P. simonii Carr.) and one species from Europe (P. cerasifera Ehrh.) contributed the bulk (72% to 90%) of the genetic background to the cultivated diploid plum. The southeastern plum gene pool was more diverse than those from California, Florida, or South Africa because of the greater contribution of P. cerasifera and P. angustifolia Marsh. to its genetic background.
A. Millie Burrell, R. Daniel Lineberger, Keerti S. Rathore, and David H. Byrne
Fifteen genetically diverse roses were evaluated for the ability to undergo somatic embryogenesis. Over the two media (MS and B5), two sugars (glucose and sucrose), and two explants (filaments and petiole) used, 20 to 30% of the `Tournament of Roses' callus was embryogenic whereas only crystalline callus was produced in cultures of `Baby Love', `Ingrid Bergman', `Perfume Delight', `Prominent', `Sunflare', and 90-202. Cultures of `Tournament of Roses' consistently produced somatic embryos whereas `Baby Love' produced no embryos. An F1 progeny of `Tournament of Roses' × `Baby Love' was chosen to test whether the ability to undergo embryogenesis in Rosa hybrida L. is heritable. Data collected from tests on F1 progeny between these genotypes suggest that the ability to undergo embryogenesis is indeed heritable in an additive fashion.
David R. Byrnes, Fekadu F. Dinssa, Stephen C. Weller, and James E. Simon
Vegetable amaranth (Amaranthus sp.), a leafy vegetable crop consumed around the world, is actively promoted as a source of essential micronutrients to at-risk populations. Such promotion makes micronutrient content essential to the underlying value of this crop. However, the extent to which micronutrient content varies by effect of genotype is not clear, leaving breeders uninformed on how to prioritize micronutrient contents as the criteria for selection among other performance parameters. A total of 32 entries across seven Amaranthus species were field-grown and analyzed for Fe, Mg, Ca, Zn, yield, height, and canopy spread comprising 20 entries at New Jersey in 2013; 12 entries at Arusha, Tanzania, in 2014; and 20 entries at New Jersey in 2015. The genotype effect was significant in all trials for Fe, Mg, Ca, Zn, total yield, marketable yield, height, and canopy spread. The Fe content range was above and below the breeding target of 4.2 mg/100 g Fe in all environments except for New Jersey 2015, where all entries were found to accumulate in levels below the target. All entries in each of the environments contained levels of Ca and Mg above breeding targets, 300 mg/100 g Ca and 90 mg/100 g Mg. None of the entries in any environment met the Zn breeding target of 4.5 mg/100 g Zn.
Katherine M. Solo, Sara B. Collins, Madalyn K. Shires, Ron Ochoa, Gary R. Bauchan, Liesel G. Schneider, Alan Henn, James C. Jacobi, Jean L. Williams-Woodward, M.R. Hajimorad, Frank A. Hale, John B. Wilkerson, Alan S. Windham, Kevin L. Ong, Mathews L. Paret, Xavier Martini, David H. Byrne, and Mark T. Windham
The eriophyid mite, Phyllocoptes fructiphilus, vectors the causal agent, Rose rosette virus (RRV), that results in rose rosette disease. Parts of the southeastern United States have remained free of the disease, except for infected plant material introductions that were eradicated. A survey of sampling points through Alabama, Georgia, and Mississippi (n = 204) revealed the southeastern border of RRV. The presence of RRV in symptomatic plant tissue samples (n = 39) was confirmed by TaqMan-quantitative reverse transcription polymerase chain reaction (RT-qPCR). Samples were also collected at every plot for detection of eriophyid mites, specifically for P. fructiphilus. Three different species of eriophyid mites were found to be generally distributed throughout Alabama, Georgia, and Mississippi. Most of these sites (n = 60) contained P. fructiphilus, found further south than previously thought, but in low populations (<10 mites/gram of tissue) south of the RRV line of incidence. Latitude was found to be significantly correlated with the probability of detecting RRV-positive plants, but plant hardiness zones were not. Plot factors such as plant size, wind barriers, and sun exposure were found to have no effect on P. fructiphilus or the presence of RRV. The reason for the absence of RRV and low populations of P. fructiphilus in this southeast region of the United States are unclear.