Search Results
Abstract
Commercial and exotic cultivars and selections of peach and nectarine [Prunus persica (L.) Batsch] were evaluated for reaction to gummosis caused by Botryosphaeria dothidea (Moug. ex Fr.) Ces & de Not. (B. ribis Gross & Dugg.). Commercial germplasm was susceptible. Mature trees of several exotic lines showed very little natural infection. ‘Eagle Beak’, Plant Introduction (PI) 43289 from China, was the most resistant to gummosis. Artificially inoculated twigs of this line gummed only slightly, although the fungus could still be isolated from some wounds after 16 months.
Abstract
A method was developed to determine the concentration of prunasin, a cyanogenic glucoside, in bark and twigs of peach [Prunus persica (L.) Batsch] trees. The procedure allowed handling of large numbers of samples with concurrent estimations of reducing sugars and ninhydrin positive materials. Prunasin was extracted with 80% ethanol, concentrated, reacted with β-glucosidase, and the resulting benzaldehyde was detected by gas liquid chromatography (GLC). The technique was rapid and did not require specialty glassware or derivitization of prunasin prior to GLC.
Abstract
‘Sunland’ peach [Prunus persica (L.) Batsch] has been released to provide a cultivar well-adapted to the southeastern United States that ripens slightly later than ’Harvester’. ‘Sunland’ is similar to ‘Harvester’ in color and firmness, but has larger fruit.
Abstract
‘Starlite’ peach [Prunus persica (L.) Batsch] has been released to provide an early white-fleshed peach for local markets. The fruit is larger and more uniform in size, shape, and maturity than ‘Springtime’, the leading white-fleshed cultivar of its season.
Abstract
Fruit of 3 of 70 trees from a cross of ‘Pekin’ peach x ‘Durbin’ nectarine [(Prunus persica (L.) Batsch)] had a dull, slightly rough surface intermediate in appearance to the shiny, smooth surface of a nectarine and the pubescent surface of a peach. Scanning electron photomicrographs of the epidermis revealed short, often multicellular, papillae 20–80 μm in length but no long hairs of the normal 200–500 μm length. Fruit buds on the three trees were glabrous in contrast to the pubescent buds of peaches and nectarines.
Abstract
Four-year-old trees of ‘Redglobe’ peach [Prunus persica (L.) Batsch] were pruned on 1 Mar. and again on 15 Aug. 1982 and the pruning wounds inoculated with spore suspensions of Botryosphaeria dothidea [(Moug. ex. Fr.) Ces & de Not. (B. ribis Gross & Dugg.)]. Spring-pruned trees were susceptible to invasion for only the first week after pruning as determined by visual gum ratings and reisolation rates. Summer-pruned trees were susceptible for a similar period, but fungal isolation frequency was much lower than for the spring-pruned trees. A benomyl-captan spray immediately after summer pruning reduced both gumming and isolation frequency.
Abstract
‘Juneprince’ peach [Prunus persica (L.) Batsch.] has been released to extend the season in moderately low-chilling areas suc5as south Georgia and as a replacement for ‘Coronet’ in medium-chilling areas. ‘Fireprince’ peach has been released to provide a cultivar for the Southeast in the season preceding ‘Redglobe’.
Two unpruned narrow-leaf and two unpruned standard-leaf peach [Prunus persica (L.) Batsch.] selections were evaluated for physiological components related to water use efficiency {WUE [carbon assimilation (A) per unit of transpiration (T)]}. The purpose of the study was to assess the value of narrow-leaf phenotypes to improve WUE in peach and separate the environmental component of canopy geometry from the genetic components. The narrow-leaf characteristic itself did not confer improved WUE. The interception of light was a key determinant of WUE in these genotypes. Internal shading of the tree by excessive leaf area reduced daily WUE measured in gas exchange studies. Canopies that intercepted more than 75% of the photosynthetically active radiation (PAR) had reduced daily WUE. Dormant season pruning of the four genotypes lowered isotopic carbon discrimination and therefore increased seasonal WUE compared to unpruned trees. None of the genotypes had a significant correlation of seasonal WUE with leaf and fruit weight. Analysis of covariance indicated that `Bounty' and both narrow-leaf genotypes had greater leaf and fruit weight than `Redhaven' for a given level of PAR interception. `Bounty' had the least internal canopy shading of the four genotypes. Genetic differences in peach growth types can be selected for factors increasing WUE as well as increased productivity. Future work in peach breeding to improve WUE and productivity must take into consideration light interception, productivity, and WUE in an integrated manner to make real progress in the efficient use of water and light in the orchard environment.
The evaluation of peach and nectarine cultivars and advanced selections for suitability of production in the southeastern U.S. has been conducted at Clemson Univ. since 2000. Currently, there are 240+ cultivars and advanced selections being tested at the university's Musser Fruit Farm in Seneca, S.C. The harvest season begins in early May and ends in the middle of September. Additionally, two on-farm grower trials were planted in the primary peach growing regions of the Piedmont (Cowpens, S.C.) and the Ridge (Monetta, S.C.). At the grower locations, advanced selections are compared with industry standard cultivars. Evaluation data collected includes bloom and ripe date, fruit set, shape, color, size, firmness, taste and disease susceptibility. Digital photos are taken to scale at commercial maturity. Evaluation information, photos, plus chill hours, variety descriptions and other valuable information are on the website. In 2004, substantial improvements were made to the site utilizing a database, search and compare tools. The website has been well received by the southeastern commercial peach growers and is utilized to assist them in cultivar selection and to learn more about peach culture in general.
Rootstock influence on bloom date and fruit maturation of `Redhaven' peach [Prunus persica (L.) Batsch] was studied over a 3-year period. Rootstock included seedlings (Lovell, Halford, Bailey, and Siberian C) and cuttings (GF677, GF655.2, Damas 1869, and `Redhaven'). Bloom dates of the various combinations differed in all 3 years, with a range of 3.6, 9.1, and 7.3 days in 1988, 1989, and 1990, respectively. Fruit development period differed each year with a range of 3.9, 5.8, and 4.4 days in 1988, 1989, and 1990, respectively. `Weighted-average harvest date also differed with a range of 3.6,2.9, and 5.6 days in 1988, 1989, and 1990, respectively. `Redhaven'/Lovell was the latest blooming and maturing combination in all 3 years of the study.