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Abstract
Pedigrees of 134 North American strawberry (Fragaria × ananassa Duch.) cultivars introduced since 1960 were used to calculate 1) the genetic contribution of founding clones to these cultivars; 2) genetic relatedness among these cultivars; and 3) inbreeding coefficients of these cultivars. Fifty-three founding clones accounted for the pedigrees of these cultivars, with a mean genetic contribution ranging from <0.1% to 11%. Cultivars were clustered according to the genetic contribution into groups strongly related to geographic region of origin. Cultivars developed in California plus those derived in large part from California germplasm were a distinct cluster. The remaining cultivars divided strongly into two geographical divisions, with cultivars of a western or northern origin primarily in the first division, and cultivars of a southern or eastern origin primarily in the 2nd division. Cluster groups within each division also were related to the region of origin of cultivars. Cultivars also were clustered on the basis of Wright’s coefficient of relationship, a measure of genetic relatedness. Cluster groups from this analysis were strongly related to region of origin of cultivars, and were similar in content to groups based on genetic contributions. Inbreeding coefficients ranged from 0.0 to 0.875, but were <0.5 for all cultivars developed from cross-fertilization. Inbreeding coefficients were related partly to region of origin of the cultivars, but this relationship was probably an indirect result of unequal numbers of generations of controlled hybridization from common ancestors. For example, cultivars developed in California, which resulted from more generations of hybridization, generally had higher inbreeding coefficients. Strategies are suggested for maintaining and increasing genetic diversity of North American breeding populations.
Experiments were conducted to determine the chilling temperature and length of time required to break dormancy in red raspberry (Rubus idaeus L.). Five weeks of 7 °C with no light was sufficient to break dormancy in `Autumn Britten', `Nova', `Polana', and `Tulameen', while at least 8 weeks were needed for `Titan'. Comparisons with various chilling unit models allowed a model to be developed that could account for the observed chilling variation. In this model, each chilling hour was weighted as follows: below 5.6 °C = 1; 5.7 to 8.0 °C = 0.5; 8.1 to 11 °C = 0; 11.1 to 13 °C = -0.5; and >13 °C = -1. Plants of `Nova' and `Tulameen' chilled before flower initiation occurred, broke dormancy, and the resulting lateral branches remained vegetative. When the plants were fruited in the greenhouse, we were able to produce a second crop on the fruiting canes when the lateral branches that had fruited were removed. These experiments show that raspberries can be manipulated so that plants chilled in mid-September in the Northern Hemisphere can be induced to fruit by the beginning of January.
Micropropagation of strawberries is an extremely effective tool to rid strawberry plants of Colletotrichum infections. The continued health of these plants depends on a vigorous sanitation program throughout the nursery system in North America. Propagating healthy strawberry plants requires a series of steps: plants are micropropagated, virus-tested, screened for fungal and bacterial pathogens, and finally grown under strict guidelines for two growing seasons in propagator's fields. In the propagator's fields, the plants are inspected for visual symptoms of diseases and checked for trueness-to-type. This paper reviews the protocols used to develop specific pathogen-tested strawberry plants in Ontario and, where appropriate, discusses alternate techniques.
Abstract
Estimated yields were compared to actual yields of red raspberries (Rubus idaeus L.) from research plots planted in stool beds at Abbotsford, B.C. and Invergowrie, Scotland and in hedge rows at Healesville in Victoria, Australia. Estimated yields, based on fruit set on 2 canes immediately prior to the start of harvest multiplied by the mean weight of 50 fruit taken at least 5 times throughout the harvest season, accurately assessed yield of the plots at all 3 locations. Accuracy of estimates was improved if plots had similar cane numbers and numbers of canes sampled were increased.
Rooted cuttings of `Antonovka' apple, `Lynwood Gold' forsythia, double-flowered kerria, common ninebark, `Goldfinger' potentilla, and `Red Prince' weigela were grown in 2-gal (6-L) nursery containers filled with 1:1 (by volume) of waste compost and composted pine bark, under three fertilizer regimes: 1) liquid nutrients [target concentrations in ppm (mg.L-1): NH4-N, 13; NO3-N, 100; P, 28; K, 120; Ca, 92; Mg, 13; Fe, 1.3; Mn, 0.27; Zn, 0.23; Cu, 0.05; B, 0.22; Mo, 0.05; Na, <50; Cl, <50; and SO4 <300] delivered and recycled twice per day via a computer-controlled multifertilizer injector; 2) same nutrient formula and concentration rate delivered fresh via the injector but without recycling; and 3) Nutryon (Polyon) 17-5-12 controlled-release fertilizer incorporated into the medium at a rate of 11 lb/yd3 (6.5 kg·m-3). With recycled liquid nutrients, all species grew the same or more than with nonrecycled nutrients, and generally the poorest growth was with controlled-release fertilizer. Foliar concentrations of K (all species), N (all species), P (forsythia, kerria, potentilla, and weigela), and Mn (forsythia, potentilla, and weigela) were higher in plants supplied with recycled and/or nonrecycled nutrients than in those supplied with controlled-release fertilizer, while foliar concentrations of Ca (ninebark and kerria) and Mg (apple, kerria, ninebark, potentilla, and weigela) were lower. Compared to nonrecycled liquid nutrients, the amounts of individual recycled nutrients were reduced by (percentage in brackets): NH4-N (30), NO3-N (78), P (76), K (46), Ca (93), Mg (96), Fe (52), Mn (43), Zn (55), Cu (60), B (83), and Mo (66).
`Seascape' strawberries were harvested and treated with various concentrations of riboflavin and placed on a lab bench for 0, 1, 2, 3, or 4 days, respectively, in a cold room at 4 °C. After each day, samples were taken and stored in a freezer at -20 °C until they were evaluated for anthocyanins content. Both exogenously applied riboflavin and storage time increased cyaniding 3-glucoside and pelargonidin 3-glucoside in the strawberry fruits. This result indicates that riboflavin could be used to increase red color in strawberries destined for processing as well as be included as a vitamin supplement in the processed products.
In greenhouse and field studies, benzyladenine (BA) and gibberellic acid (GA3) applied together as a foliar spray increased runner production in dayneutral strawberries (Fragaria ×ananassa Duch.) but not when applied separately. Runner production increased linearly with increased BA concentration to 1800 mg·L–1. At high dosages, GA3-treated plants produced elongated internodes that, in the field, led to fewer daughter plants. In Florida, daughter plants derived from plants sprayed with the growth regulators increased yield by up to 10% in fruiting experiments. To induce runnering in the field and greenhouse, a treatment with BA at 1200 mg·L–1 and GA3 at 300 mg·L–1 is recommended. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine (benzyladenine); gibberellic acid A3; gibberellic acids A4 and A7.
Abstract
A trial of six raspberry (Rubus ideaus L.) cultivars was established to study the effects of primocane removal, using dinoseb, on yield and its components. In 1982 through 1984, sprays were applied using both single and multiple follow-up treatments with and without shielding the primocanes in the immediate stool area. The effects of cultivars and treatments on yield components were studied by two-dimensional partitioning of the variation in marketable yield. When primocanes were removed, the cultivars had fewer canes, larger fruit, and increased marketable yield. Cultivars differed in their requirements for treatment because some cultivars produced canes more readily than others. Higher-yielding cultivars generally had fewer canes and greater length of laterals. Chemical name used: 2-(1-methylpropyl)-4,6-dinitrophenoI (dinoseb).
Pedigrees of 137 red raspberry (Rubus idaeus L.) varieties released throughout the world since 1960 were used to calculate: 1) the genetic contribution of founding clones to these varieties; 2) genetic relatedness among them; and 3) their inbreeding coefficients. Fifty founding clones contributed to the pedigrees of these varieties with a mean genetic contribution ranging from <0.1% to 21%. Varieties were clustered according to the genetic contribution into groups strongly related to geographical origin. Varieties developed in the former USSR and derived from `Novost Kuzmina' formed a distinct cluster. The remaining varieties were clustered in groups based mainly on whether they were of North American or European origin. Varieties were clustered also on the basis of Wright's coefficient of relationship-a measure of genetic relatedness. Cluster groups were related to their geographical origin and the varieties within the groups could be traced to similar intermediate parents. Inbreeding coefficients ranged from 0.0 to 0.625 and were related, in part, to the numbers of generations of controlled hybridization from common ancestors. The British group, with the largest number of generations of breeding, had a low mean inbreeding coefficient, indicating that inbreeding can be minimized with attention to the mating system. Strategies are suggested for maintaining and increasing the genetic diversity in the world's red raspberry breeding populations.
This article shares survey results provided by both consumers and growers regarding the University of Florida Biodiversity Certified Plants for the Rapidly Expanding Urban Landscape Market project conducted at the University of Florida (UF). The overall goal of this project was to develop and test a scientifically based, UF-trademarked process for the certification of high-quality, commercially available, wildlife-friendly plants for the green industry. The objectives of two surveys that targeted consumers and growers, respectively, were to assess consumer and grower attitudes, knowledge, and behaviors pertaining to wildlife-friendly plants and a proposed certification. The consumer survey results (n = 868) indicated that respondents (consumers) strongly agreed with purchasing wildlife-friendly plants, and that respondents would benefit from the proposed certification. The certification could help consumers gain a better understanding of which plants are wildlife-friendly at the point of purchase. Nearly half of consumers reported an inability to identify wildlife-friendly plants in the store, which hinders them from purchasing. The grower survey results (n = 75) indicated that respondents were willing to offer biodiversity-certified plants. More growers rated themselves as innovators (the most innovative category) in terms of adopting innovations than any other diffusion of innovations category (early adopter, early majority, later majority, hesitant, or none of these), although the perceived cost of obtaining the certification was seen as a potential barrier toward grower adoption of the certification. These findings indicate that the proposed certification would be successful with appropriate and tailored marketing materials for both growers and consumers.