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In the Southeast spring frosts often kill all or part of the flowers on peach trees. Increased flower bud density is one mechanism that increases the likelihood of enough flowers surviving to produce a crop. Mean buds per node in-North Carolina varied in 1986 from 1.6 for `Harko' to 0.4 for `Topaz'. The effect of environment on bud density was unknown. Therefore, for 3 years we compared the bud density of 25 peach and nectarine cultivars grown in completely randomized designs (4 reps per location, 10 twigs per tree) in Georgia and North Carolina. Genotypie variability was greater than that due to location or year effects. Cultivars selected for high bud density in one location can be expected to have high densities at other locations.
Spring frosts often kill all or a portion of the flowers on peach [Prunus persica (L.) Batsch] trees in the southeastern United States. Increased flower bud density increases the likelihood of sufficient flowers surviving to produce a crop. The effect of environment on flower bud density (buds/node) was studied using two locations over 3 years. Bud density of 25 peach and nectarine varieties grown in completely randomized designs was measured in Georgia and North Carolina. Genotypic variability was greater than location or year effects. Varieties selected for high bud density at one location can be expected to have high densities at other locations with similar chilling.
To determine the earliest developmental stage at which isozyme screening could be accomplished, 10 isozyme systems were examined in peach [Prunus persica (L.) Batsch] for differential expression during development. Differences in isozyme expression based on stage of development were detected in nine systems. The earliest stage for complete screening of most isozymes examined is in l-month-old seedlings. The significance of these results relative to genetic mapping is discussed.
Abstract
Phenolic compounds extracted from leaf tissue of 8 poinsettia cultivars (Euphorbia pulcherrtma willd. ex. Klotzsch) grown in a vegetative state were analyzed using 2-dimensional paper chromatography to determine if they could be biochemically distinguished. Six of the 8 cultivars studied, closely related on the basis of presumed ancestry and previous biochemical studies, exhibited similar chromatographic patterns. The other two cultivars, each having diverse, unrelated genetic backgrounds, exhibited only minor differences in their phenolic profiles. Therefore, two-dimensional chromatographic analysis of phenols did not successfully aid in cultivar identification.
Abstract
Thirty-six peach and nectarine [Prunus persica (L.) Batsch] cultivars were evaluated for flower bud number (flower buds/node) over 2 years. Cultivar, year, and year × cultivar effects were highly significant. Cultivars released from California breeding programs generally had fewer flower buds than those from eastern U.S. programs, suggesting that selection for cropping consistency in eastern breeding programs has resulted in release of cultivars with many flower buds. Variance component estimates from this study and from 2 years of sampling trees of ‘Redhaven’ indicates that sampling over years and increasing the number of shoots sampled per tree is warranted. Variability among trees within cultivar was low.
A controlled cross between Buddleja davidii var. nanhoensis (Chitt.) Rehd. `Nanho Purple' and B. lindleyana Fort. ex Lindl. produced a hybrid. Pollen viability, male fertility, and the floral and vegetative characters are presented with a Latin diagnosis. Buddleja × luteolufaucia Elliott and Fantz is proposed as the name for this hybrid. Hybridity was confirmed using RAPD analysis.
Abstract
Fruit anthocyanins (ACY) of eight Prunus spp. representing two subgenera (subg.) and three sections (sect.) were analyzed using high-performance liquid chromatography (HPLC). Fruit of P. angustifolia Marsh., P. hortulana Bailey, and P. maritima Marsh. all North American members of subg. Prunus sect. Prunocerasus, were qualitatively identical in ACY composition, containing cyanidin-3-glucoside and cyanidin-3-rutinoside. Fruit of P. cerasifera Ehrh. and P. spinosa L., both Eurasian members of subg. Prunus sect. Prunus, contained small amounts of peonidin-3-gIuco-side and peonidin-3-rutinoside, in addition to the 3-glucoside and 3-rutinoside of cyanidin. Fruit of P. besseyi Bailey and P. pumila L. (subg. Lithocerasus sect. Microcerasus) contained cyanidin-3-glucoside and cyanidin-3-rutinoside. Fruit of P. pumila also contained trace amounts of peonidin-3-rutinoside. Fruit of P. japonica Thunb., a Chinese member of subg. Lithocerasus sect. Microcerasus, showed a complex ACY profile distinct from P. besseyi and P. pumila.
Abstract
‘Contender’ peach [Prunus persica (L.) Batsch] is being released to fulfill the need for a high-quality, consistent-cropping, yellow-fleshed freestone cultivar ripening between ‘Loring’ and ‘Elberta’.
Eighteen isozyme systems were surveyed in the peach [Prunus persica (L.) Batsch.] plant introduction collection. Seven systems were polymorphic. Three previously unreported isocitrate dehydrogenase (IDH; EC 1.1.1.41), three malate dehydrogenase (MDH; EC 1.1.1.37) and two shikimate dehydrogenase (SDH; EC 1.1.1.25) banding patterns were detected in the clones. Isocitrate dehydrogenase was dimeric in structure, with two alleles present at a single locus. Malate dehydrogenase was dimeric in structure, with three alleles present at the fast locus, while a second locus was monomorphic. Shikimate dehydrogenase was monomeric, with one allele present in most clones, while PI 113452, PI 113650, and PI 117679 were heterozygous for a slow SDH allele. Electrophoretic evidence suggests PI 113452, PI 113650, and PI 117679 are peach × almond (P. dulcis Webb) hybrids, since they were heterozygous for alleles previously reported only in almond.
Abstract
In the article “Chilling Requirement of Post-rest Heat Accumulation as Related to Difference in Time of Bloom Between Peach and Western Sand Cherry,” by Dennis J. Werner, Bruce D. Mowrey, and Eric Young [J. Amer. Soc. Hort. Sci. 113(5):775-778, September 1988], in the legend of Fig. 2, second line, “14 hr” should read “1400 hr”.