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- Author or Editor: Dennis J. Werner x
Catalase isozymes were examined in a wide range of peach [Prunus persica (L.) Batsch] cultivars representing historical U.S. cultivars, commercial cultivars from numerous North American breeding programs, and the peach plant introduction (PI) collection. All historical peach cultivars from the United States and those released from commercial breeding programs were fixed for the slow (Cat l-2) allele, with the exception of `Belle of Georgia', `Honeyglo' nectarine, and various cultivars from the Univ. of Florida breeding program, which possessed a fast-migrating (Cat 1-l) allele in homozygous or heterozygous state. Polymorphism was revealed in the 51 peach PI clones examined, with allelic frequencies of 0.69 and 0.31 for the Cat l-2 and Cat l-1 alleles, respectively. Most PIs that originated directly from China were homozygous Cat l-l/Cat l-l, while most PI clones introduced from Europe were homozygous Cat l-2/Cat l-2. Examination of the catalase genotype of cultivars previously proposed as the possible male parent of `Belle of Georgia' (`Champion', `Early Crawford', `Late Crawford', `Oldmixion Free', and `Stump-the-World') revealed that none of these cultivars could have been the male parent of `Belle of Georgia'. Segregation data from various peach crosses was consistent with the hypothesis that catalase polymorphism could be explained by the presence of two alleles at a single locus.
Stokes aster is a herbaceous perennial native to the southeastern United States. Stokesia is a monotypic genus belonging to the tribe Vernonieae Cass. (family Asteraceae Dumont). The level of genetic diversity within the genus is unknown. The goal of this study was to determine the level of genetic diversity and relatedness among cultivars of stokes aster. The genetic relatedness among 10 cultivars of stokes aster, one accession of Vernonia crinita Raf. (syn. V. arkansana DC.), and one accession of Rudbeckia fulgida Ait. var. sullivantii (Beadle et Boynton) Cronq. `Goldsturm' was estimated using 74 randomly amplified polymorphic DNA (RAPD) primers. Similarity indices suggest that cultivars of stokes aster are very closely related, with values for all pairwise comparisons of cultivars of stokes aster ranging from 0.92 to 0.68. One cultivar, `Omega Skyrocket', had markedly lower similarity indices from the other cultivars, ranging from 0.72 to 0.68. Similarity indices between stokes aster and Vernonia and between stokes aster and Rudbeckia were 0.44 and 0.50, respectively.
Eastern redbud (Cercis canadensis L.) is a commonly used small landscape tree. Compact growth, purple leaf color, and weeping architecture are three popular ornamental phenotypes. Inheritances of weeping architecture and purple leaves have been reported previously. Inheritance of compact growth habit and its genetic linkage with the weeping and purple leaf genes have not been reported. In the present research, the inheritance of compact growth derived from ‘Ace of Hearts’ was explored in the F1, F2, and reciprocal backcross families resulting from the controlled hybridization of ‘Ruby Falls’ (normal growth/weeping architecture/purple leaf) × ‘Ace of Hearts’ (compact growth/nonweeping architecture/green leaf). All 27 F1 individuals were nonweeping, green-leaved, and noncompact. A total of 572 F2 progeny were obtained, and subsequent analysis of segregation revealed a single recessive gene controlled compact growth habit. Analysis of reciprocal backcross families confirmed this result as well. Weeping architecture and purple leaf color were also controlled by single recessive genes, confirming findings presented in previous studies in another redbud family. No linkage between the three genes was detected. This research is the first to report the inheritance of compact growth in eastern redbud and confirms independent assortment between the compact, purple leaf, and weeping genes.
Abstract
Fruit trees usually are hybridized outdoors due to the difficulty and expense of maintaining trees in greenhouses. Hybridizations often are lost due to freeze injury of fruit after pollination. The use of protective cages or screen houses to protect hybridizations from freeze injury has been advocated and utilized by some tree fruit breeders (2), but many of the proposed structures are cumbersome and difficult to construct. This report describes the design and performance of cages which can be built for about $25.00 per tree and can be constructed in about 45 min.
Abstract
A technique is described for obtaining nondestructive estimates of shoot and root fresh weight using Archimedes’ principle that the buoyancy of an object is equal to its volume times the density of the submersion fluid. Apple and peach seedlings grown in solution and sand cultures for 14 weeks were measured periodically using this technique. Destructive measurements also were taken for comparison. Estimated and actual shoot weights were not significantly different for seedlings grown in a solution culture; however, they were significantly different in sand culture. Coefficient of determination (r 2) values of estimated shoot weight regressed on actual shoot weight were over 0.99 for all groups of seedlings.
Abstract
Flower bud respiration of ‘Redhaven’ peach [Prunus persica (L.) Batsch] remained relatively constant during rest and increased rapidly after rest termination, but stem tissue respiration remained relatively constant. Three seedling rootstocks (Lovell, Nemaguard, Siberian C) had no significant effect on respiration of flower buds. Stem tissue respiration was significantly higher on seedling rootstocks of Siberian C on most dates, as compared to Nemaguard, with Lovell generally intermediate.
Abstract
Cytokinin (6-BA) was applied to the dormant shoots of young apple (Malus domestica Borkh.) and peach [Prunus persica (L.) Batsch.] trees after applying all combinations of shoot and root chilling during rest. After greenhouse forcing, bud-break, new shoot dry weight, and new root growth were greatest in apple trees with both shoot and root chilling. In contrast, only shoot chilling was necessary for maximum response in peach. Applied 6-BA substituted for root chilling in apple trees that had only the shoot chilled, resulting in budbreak equal to trees that had both the shoot and root chilled. Applied 6-BA had no significant effect on peach budbreak or new shoot and root growth. Chemical name used: 6-benzyladenine (6-BA).
Abstract
In the article “6-BA Applied After Shoot and/or Root Chilling and Its Effect on Growth Resumption in Apple and Peach” by Eric Young and Dennis J. Werner (HortScience 21:280-281, Apr. 1986), “0.5% Silaid” in the 20th line, 3rd column, p. 280 should read “0.5% Silwet (Union Carbide).”