Search Results

You are looking at 61 - 70 of 5,192 items for :

Clear All

and five- to 25-fold, respectively. Based on their results, and comparing their data with the contrasting observations from other rose salinity studies, Cabrera and Perdomo (2003) contended that rootstock selection was a key factor involved in

Free access

Significant response to selection for budbreak number (NB) based on data recorded on 1-year-old shoots of young apple (Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.) seedlings (Expt. I) and branches from adult seedling trees (Expt. II) has been demonstrated in clonally propagated seedling trees. Between family variation for NB was low and masked by year × family interaction effects. Realized heritability for NB was estimated as 40% to 60%. Correlated response in uniformity and position of budbreak, and in the number and length of side shoots, was found. Association between the time of budbreak (TB) and NB, according to midparent and cross groupings, and according to the parental means, indicate a positive genetic correlation between these traits. Where data on adult trees were used as a measure of selection response and tested on young clonal trees, significant response and genetic variation was shown, confirming the presence of utilizable genetic variance and that this procedure may be successfully applied as an early screening method for increased budbreak in adult trees. Combined selection utilizing genetic variance between crosses as well as within crosses is proposed as the best procedure to increase the frequency of seedlings with increased budbreak and to improve adaptation to low winter chilling conditions.

Free access

Crabapples (Malus spp.) are commonly planted ornamental trees in public and private landscapes. Hundreds of selections are available that represent a wide range of growth habits, ornamental traits, and varying degrees of resistance/susceptibility to disease. We distributed 1810 questionnaires in 13 states (Oregon, Washington, Utah, Colorado, Minnesota, Iowa, Missouri, Illinois, Indiana, Michigan, Ohio, New York, and Pennsylvania) to members of either nursery and landscape associations or the Associated Landscape Contractors of America (ACLA, Herndon, Va.) to identify crabapple preferences across a broad geographic region of the United States. We also were interested in learning if regional disease problems were important to green-industry professionals as they decide which crabapples to include in their inventories. Our respondent population numbered 511 (28.2% response rate). A large percentage of respondents (79.4%) said their retail clients focused mostly on fl ower color when choosing crabapples for the home landscape, while commercial clients showed slightly more interest in growth habit (32.5%) than fl ower color (28.7%). `Prairifire' was identified by respondents in all regions, except the west-central (Colorado and Utah), as the crabapple most frequently recommended to clients when tree size is not important. Respondents in the west-central region most often (48.7%) recommend the fruitless selection `Spring Snow'. Respondents in all regions, except the west-central, identified apple scab (Venturia inaequalis) as the most prevalent crabapple disease and named scab-susceptible `Radiant' as the selection most frequently discontinued.

Full access

cause injury and subsequently economic losses. Available data for the frost tolerance, supercooling, and cold acclimation of walnut cultivars and selections, especially Iranian native selections, are scarce. This study was conducted to screen a range of

Free access

Twelve peach [Prunus persica (L.) Batsch] seedling rootstocks [Lovell, Nemaguard, Flordaguard, 14DR51, five Guardian™ (BY520-9) selections, and three BY520-8 selections] budded with `Cresthaven' were planted in 1994 and evaluated through 2000 to determine performance under commercial management practices. Mesocriconema xenoplax population densities were above the South Carolina nematicide treatment threshold of 50 nematodes/100 cm3 of soil after 1996. However, symptoms of peach tree short life (PTSL) were not observed. Tree mortality was less than 14% through 1999, with most of the dead trees exhibiting symptoms consistent with Armillaria root rot. About 13% of the surviving trees in 1999 were removed in 2000 due to symptoms of phony peach. There were no differences in tree mortality among rootstocks. Tree growth, photosynthesis, and suckering varied among rootstocks, but leaf conductance, internal CO2, and leaf transpiration did not. Foliar calcium, magnesium, iron, and phosphorus varied among rootstocks, but all were within the range considered sufficient for peach trees. Fruit yield varied among rootstocks, but yield efficiency did not, indicating that higher yield corresponded with larger trees. Bloom date did not vary among rootstocks, but harvest date was advanced as much as 2 days for some rootstocks, compared to Lovell. Fruit weight varied among rootstocks but skin color, flesh firmness, and soluble solids content were similar. All rootstocks performed satisfactorily for commercial peach production.

Free access

Fruit quality of 24 selected strawberry cultivars and selections were evaluated. There were great variations in the contents of soluble solids, titratable acidity, carbohydrates, organic acids, and ascorbic acid among different cultivars, reflecting primary genetic differences. Fructose, glucose, and sucrose were found to be the three major sugars, comprising >65% of the total soluble solids in strawberry. Fruit contained lower sucrose compared to fructose and glucose, whereas leaves contained comparable amounts of fructose, glucose, and sucrose. Citric acid was the major organic acid in strawberries. Strawberries were also rich in ascorbic acid. Leaves were much higher in ascorbic acid than fruit. There appeared to be no correlation between fruit and leaves on carbohydrate, organic acid, and ascorbic acid contents.

Free access
Author:

Seedling selections in pomegranates began in 1986. `Giant Green Sweet' (GGS) was used as the female parent. GGS was characterized by fruit size from 340 to 500 g, a green color with slight blush, thin fruit coat, hexalobate calyx, and semi-open ovary with 8 to 12 loculi. The seeds are red, abundant, juicy, and sweet. The seeds contain 15% to 16% soluble solids. The male, pollinating cultivars in the same garden were `Giant Red Sweet', `Giant Horse Teeth', `White Sweet', `Red Sour', `Bing Tang Zi', and `Qing Gang Liu'. Seeds were harvested from fruit that were open-pollinated and weighed 500 g. Seeds were germinated and planted at the end of March. One-year-old seedlings grew to 30 to 50 cm. Two-year-old seedlings grew to 1 to 1.5 m tall with many branches. Seedlings passed the juvenile period after 3 years of growth. Some seedlings blossomed, and a few blossoms developed into fruit. Seedlings were adult by the fourth year, and all of them blossomed and developed fruit. This is a shorter interval to maturation than the parent cultivars. Fruits were located from the lower middle of the tree crown to the top. Adult seedlings produced fruit of ≈400 g with a few seedlings producing fruits of 500 to 600 g. There were 400 to 500 seeds per fruit averaging 40 g per 100 seeds. Seeds from the offspring were bright red and larger than those of the female parent. Fruit flavor was similar to the female parent. Offspring were more cold hardy than the parent cultivars. There were no signs of cold injury in hybrid seedlings to –19°C. This study indicates that seedling selection in pomegranates has a high potential to create higher yield and quality pomegranates. Continuing experiments will reselect the best offspring to develop higher quality cultivars.

Free access

breeding lines, resistance loci for separate diseases may be contributed by different parents in the pedigree but located on the same chromosome and, therefore, linked in repulsion. Selection for coupling phase recombination events that combine resistance

Open Access

Abstract

A study was conducted to investigate the extent of genetic variations and the interrelationships of several quality traits of cultivars of navy and pinto bean (Phaseolus vulgaris L.) grown at 3 locations in Michigan. The measured traits were seed weight, initial weight of solids, surface color of dry and processed beans (L, aL, bL), weight of soaked beans, hydration ratio, clumps, splits, texture, washed and drained weight, and processed bean moisture. Significant cultivar differences were observed for most of the traits in both classes of beans. Location effects were highly significant for all traits. Certain traits showed significant cultivar × location interactions. Phenotypic correlation coefficients among pairs of characters indicated that, with few exceptions, there were low assocations among quality characters. Principal component analysis confirmed the independence of traits. A selection strategy based on a tandem selection procedure followed by construction of selection indices was suggested.

Open Access

’, conferred by a dominant allele at a single locus ( Mehlenbacher et al., 1991 ), has been extensively used in the hazelnut breeding program at Oregon State University (OSU). Most resistant selections from the breeding program carry ‘Gasaway’ resistance. In

Free access