in spring” in China ( Wang, 2010 ; Wang et al., 2015 ). They have been cultivated as ornamentals in China since the Han Dynasty (202 BC) and are esteemed by professional and amateur gardeners. Crabapples from China were introduced to Europe and the
Ornamental crabapples ( Malus sp.), with their breathtaking display of resplendent blooms in spring and colorful fruit in autumn, are one of the most popular ornamental plants adorning the northern hemisphere ( Cronin et al., 2020 ; Fiala, 1994
Abstract
Data on flower characteristics and honey bee (Apis mellifera L.) foraging behavior were collected on 34 ornamental crabapple and five apple cultivars. Honey bees showed a strong fidelity to foraging on either non-white or white flowers. Nectar reward had little or no correlation to this behavior. Reflectance readings in a blue range (at 436 nm) were more closely correlated with flower-color categories than ultraviolet reflectance. Considering bee behavior and bloom timing, ‘Manchurian’, ‘Snowdrift’, and ‘Golden Hornet’ are potential ornamental crabapple pollenizers for ‘Delicious’ under Pacific Northwest conditions.
; Shay et al., 1962 ). Crabapples are among the most widely cultivated ornamental trees in the northeastern and midwestern regions of the United States and in southern Canada. Crabapple trees vary in size and shape and can provide four seasons of interest
the atmosphere, causing anoxia in flooded tissues, which significantly impacts plants' physiologic metabolism, leading to the inhibition of plant growth and development and even death ( Kozlowski 1984 ). As an ornamental tree, crabapples ( Malus sp
In commercial fruit farms and ornamental tree nurseries, producers generally use integrated pest management tactics, including pesticide treatments, to control a variety of insect and plant disease pests ( Beckerman, 2018 ; Braman et al., 2015
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.
Crabapples (Malus spp.) are an important group of ornamental trees that are morphologically and genetically very diverse. Crabapples are represented by 35 species (and their hybrids). Some Malus species freely hybridize and numerous cultivars originated as open-pollinated seedlings of questionable parentage. Isoenzyme analysis could provide a more reliable measure to verify cultivars and putative pedigrees. Five enzyme systems were well resolved and polymorphic using standard starch gel electrophoretic techniques. Enzymes evaluated include: phosphoglucose isomerase (PGI), malate dehydrogenase (MDH), 6-phosphogluconate dehydrogenase (6-PGD), aspartate aminotransferase (AAT), and phosphoglucomutase (PGM). After electrophoresis, PGI, MDH, and AAT exhibited one distinct polymorphic region of activity whereas 6-PGD and PGM exhibited at least two regions. Isoenzyme profiles were constructed for each polymorphic region for 45 crabapples which demonstrated a high degree of variability. Most cultivars could be uniquely identified using the five enzyme systems. PGM and 6-PGD were most useful in characterizing among the selected cultivars.
Abstract
Pollen specimens from 8 ornamental crabapples (Malus spp.) were compared using the scanning electron microscope (SEM) to determine if they, like apple cultivars, can be distinguished by pollen characters. All pollen grains were approximately equivalent in size, tricolpate, elliptical in shape, with tectate-perforate exine type. Exine riding was superficially similar among all 8 crabapples, but close examination revealed sufficient detail to distinguish between them. Pollen from 4 of the 8 crabapples, M. baccata var. mandshurica (Maxim.) C. K. Schneid., M. × purpurea (Hort. Barbier) Rehd. ‘Lemoinei’, M. × robusta (Carriere) Rehd. and M. Sargenta Rehd. possessed collared perforations. Among these M. baccata var. mandshurica and M. × purpurea ‘Lemoinei’ pollen had grains with parallel, unbroken exine ridging, while M. × robusta and M. sargentii grains commonly exhibited whorling of ridges. Spacing between exine ridges were wider on pollen grains of M. baccata var. mandshurica than on those of M. × purpurea ‘Lemoinei’, but M. × robusta and M. sargentii could not be distinguished using pollen characters alone. The remaining 4 crabapples lacked collared perforations and were further subdivided by perforation frequency. M. floribunda Siebold ex Van Houtte and M. × purpurea (Hort. Barbier) Rehd. pollen displayed a large number of simple perforations while pollen from M. × purpurea ‘Aldenhamensis’ and M. × zumi calocarpa (Matsum.) Rehd. yielded lower perforation frequencies. M. floribunda pollen had more closely spaced exine ridges than M. × purpurea. M. × purpurea ‘Aldenhamensis’ differed from M. × zumi var. calocarpa in that its pollen generally had larger perforations.
Abstract
Malus × ‘Naragansett’ combines multiple disease resistance and superior ornamental characteristics for reduced landscape maintenance. Crabapples are of utmost significance to the nursery industry, landscape architects, and gardeners alike as they are the most versatile and widely cultivated small landscape tree throughout the northern United States and southern Canada. ‘Naragansett’ is a noteworthy addition to the long list of crab-apple cultivars, as very few combine disease resistance and superior landscape characteristics. In the recent survey by Nichols (2), only three of the 48 recommended cultivars, species, and varieties of the more than 700 surveyed were disease free, while the other 45 displayed varying degrees of resistance or tolerance. ‘Naragansett's’ growth habit is in scale with many landscape situations, and the plant requires low maintenance due to its open branch structure and disease resistance.