Each seed, when germinated, can grow to become a new specimen tree. However, the new tree inherits characteristics of both its parents, and it will not grow true to the variety of either parent from which it came. That is, it will be a fresh individual with an unpredictable combination of characteristics of its own. Although this is desirable in terms of producing novel combinations from the richness of the gene pool of the two parent plants such sexual recombination is the source of new cultivars , only rarely will the resulting new fruit tree be directly useful or attractive to the tastes of humankind.
Most new plants will have characteristics that lie somewhere between those of the two parents. Therefore, from the orchard grower or gardener's point of view, it is preferable to propagate fruit cultivars vegetatively in order to ensure reliability. This involves taking a cutting or scion of wood from a desirable parent tree which is then grown on to produce a new plant or " clone " of the original. In effect this means that the original Bramley apple tree, for example, was a successful variety grown from a pip, but that every Bramley since then has been propagated by taking cuttings of living matter from that tree, or one of its descendants.
The simplest method of propagating a tree vegetatively is rooting or taking cuttings. A cutting usually a piece of stem of the parent plant is cut off and stuck into soil. Artificial rooting hormones are sometimes used to improve chances of success. If the cutting does not die from rot-inducing fungi or desiccation first, roots grow from the buried portion of the cutting to become a new complete plant.
However, although this works well for some plants such as figs and olives , for most fruit tree cultivars this method has much too low a success rate to be commercially viable.
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Root cuttings pieces of root cut off and induced to grow a new trunk are also not used to propagate fruit trees, although this method is successful with some herbaceous plants. A refinement on rooting is layering. This is rooting a piece of a wood that is still attached to its parent and continues to receive nourishment from it. The new plant is severed only after it has successfully grown roots.
Layering is the technique most used for propagation of clonal apple rootstocks. The most common method of propagating fruit trees, suitable for nearly all species, is grafting onto rootstocks. This in essence involves physically joining part of a shoot of a hybrid cultivar onto the roots of a different but closely related species or cultivar, so that the two parts grow together as one plant. The process of joining the two varieties must ensure maximum contact between the cambium the layer just below the bark of each, so that they grow together successfully.
Grafting is a preferred method because it not only propagates a new plant of the desired hybrid cultivar, it usually also confers extra advantages as a result of the characteristics of the rootstocks or stocks , which are selected for characteristics such as their vigour of growth, hardiness and soil tolerance, as well as compatibility with the desired variety that will form the aerial part of the plant called the scion.
For example, grape rootstocks descended from North American grapes allow European grapes to be grown in areas infested with Phylloxera , a soil-dwelling insect that attacks and kills European grapes when grown on their own roots. Two of the most common grafting techniques are "whip and tongue", carried out in spring as the sap rises, and "budding", which is performed around the end of summer. One reason for grafting onto rootstocks is that this enables the grower to determine the tree's eventual size. Another desirable characteristic of rootstocks is environmental adaptability.
Apple tree size classes number from one to ten in increasing height and breadth. A "10" is the standard sized tree with no dwarfing and will grow to 20 feet 6.
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Because good, comprehensive books and reviews have been produced that describes mendelian traits and QTLs in Rosaceae fruit trees Dirlewanger et al. Instead we describe high-density reference genetic linkage maps in pear, apple and Prunus. Recently, Terakami et al. On the basis of whole-genome sequencing of P. The number to the left of each marker indicates genetic distance cM. SSR markers green, underlined were developed from pear. SSR markers red, italicized were developed from apple. Several apple reference genetic linkage maps have been published.
Recently, Verde et al. RosCOS markers were identified from rosaceous unigenes comprised of two or more ESTs corresponding to single-copy genes in Arabidopsis Cabrera et al. The obtained maps spanned Very recently, genotyping-by-sequencing GBS , a new methodology based on high-throughput sequencing, was applied for genome mapping in sweet cherry Guajardo et al. MAS can accelerate selection and reduce the progeny size and the cost of raising individuals to maturity in the field, especially in fruit trees Luby and Shaw Since several characteristics were already analyzed by genome mapping, QTL analysis, or both, the positions of responsible genes loci were identified in genetic linkage maps and tightly linked molecular markers were identified; these data are deposited in the public database of the Applied Crop Genomics Research Center http: DNA markers have been identified that are associated with genes for resistance to scab disease caused by Venturia nashicola Gonai et al.
Self-incompatibility in Japanese pear is controlled by a single multi-allelic S -locus, and S -genotype identification is important for breeding and selection of pollen donors for fruit production. Several molecular assays for rapid and reliable S -genotype determination have been established, such as polymerase chain reaction—restriction fragment length polymorphism PCR-RFLP analysis Ishimizu et al.
Molecular markers associated with the following fruit-related traits were also revealed: These markers can be used for MAS in Japanese pear breeding programs. Molecular markers associated with genes of interest in Japanese pear and their positions in genetic linkage maps.
It is expected that comparative genomics in Rosaceae fruit trees will be able to integrate conserved candidate genes, molecular markers associated with interest traits, and QTLs, in order to verify how the genetic and molecular factors control traits like fruit quality and texture across species and genera. Therefore, synteny or comparative genome mapping is an important approach, which determines the homologous genes of related species, as well as the co-linearity conservation of the gene order among conserved genomic regions.
Nucleotide repeats were detected in the amplified fragments of pear and apple by both sequencing and Southern blot analyses, and the differences in fragment sizes between pear and apple were due mainly to the differences in the number of such repeats. The SSR markers are applicable across genera in the tribe Pyreae, subtribe Pyrinae, which includes apple, pear, quince Cydonia oblonga Mill. These findings suggest that all chromosomes of the genera in the tribe Pyreae show co-linearity despite considerable differences in the genome sizes, which range from 1.
The marker transferability is extremely high within Prunus. Furthermore, Mnejja et al.
Of the SSRs derived from Prunus species, In contrast, only SSR markers developed for various Prunus species have been intensively used to compare Prunus linkage maps Dirlewanger et al. The distribution and order of SSR markers in all Prunus species show complete synteny except for a reciprocal translocation between LGs 6 and 8 detected in peach and almond Dirlewanger et al. The SNP-based sweet cherry maps displayed high synteny and co-linearity of all eight LGs with the Prunus reference map and with the peach genome v1. Similarly, Yamamoto et al. Furthermore, several other reports have showed synteny within Rosaceae plants Sargent et al.
In this manuscript, we describe to focus recent progress on whole-genome sequences, genome-wide SNP and SSR markers, construction of reference genetic linkage maps, and synteny studies in Rosaceae fruit trees, which will help us to develop new cultivars with desirable traits by MAS and new genomic-based strategies in breeding programs. Genetic improvement of Rosaceae fruit trees is strongly hampered by their large tree size, long generation, an extended juvenile phase for seedling Luby and Shaw , Rikkerink et al.
Therefore, it is considered that MAS and marker-assisted breeding can accelerate selection and reduce the progeny size and the cost of raising individuals to maturity in the field Luby and Shaw , Rikkerink et al. However, attempts to MAS in fruit tree breeding programs remain limited for a few simply inherited traits, because marker development for MAS via bi-parental QTL mapping is also hindered by the same complications. Newly developed high-throughput genotyping technologies such as SNP chips and genotyping using NGS have enabled new genomic-based strategies such as genome-wide association studies GWAS , which are an alternative to bi-parental QTL mapping in long-lived perennials.
Selection based on genomic predictions of breeding values, i. The robust and evenly distributed genome-wide SNP markers combined with reference genetic linkage maps, help us to use new genomic-based strategies such as GWAS and GS, which are now emerging as powerful tools in pear, apple, and forest tree breeding programs Grattapaglia and Resende , Iwata et al. National Center for Biotechnology Information , U. Journal List Breed Sci v. Published online Jan 1.
Author information Article notes Copyright and License information Disclaimer. Received Sep 10; Accepted Jan This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. These include 1 a one-quart graduated measuring container, preferably a clear one, and, 2 a set of measuring spoons. Do not store pesticides where they will be exposed to drastic changes in temperatures, flames like a gas water heater or heating unit , or ventilation ducts.
This is not a wise approach and can pose unwarranted hazards, not only to the applicator, but also to the plants being treated and even to the environment.
Recommended rates of pesticides are based on amounts needed for control. Applications in excess of recommended rates contribute unnecessarily to environmental contamination without increasing the level of control. When you purchase a pesticide for use around your home, buy small quantities, always keeping in mind your most significant pest problems.
Large quantities of pesticides will present problems associated with storage, odor, cost, and ultimately disposal. When an excessive amount of pesticide is purchased or mixed up and not used, store it temporarily until the remainder can be used according to label directions. Do not attempt to pour left over pesticides down any drainage system. This can contaminate the water supply.
Use of excess amounts in a well-landscaped homeowner environment may result in run-off into non-target points or unnecessary exposure of humans and pets to high levels of pesticides. All factors increase the liability of homeowners who simply intended to grow fruit for the family.
Home Tree Fruit Production and Pest Management
For fruit trees with heavy infestations, pesticide applications may be repeated every days to protect new growth. Follow all label directions when using any pesticide and observe harvest intervals waiting periods from the last spray. Seven Tips for Good Control 1. Mix fresh spray for each application.
Add spray materials to a little water in a clean container. Smooth out all the lumps before you pour the materials into the sprayer. Straining the spray mixture through a screen when filling the sprayer helps to prevent a clogged nozzle. Stir the spray mixture or shake the sprayer often to prevent chemicals from settling out.
Dormant sprays are important because some pests attack before visible growth begins. A dormant oil spray is applied to control over-wintering pests. Certain fungicides are applied during the dormant period to control some diseases such as peach leaf curl. Spray soon after rain to help prevent diseases from seriously infecting foliage and fruit. Heavy rain may wash protective chemicals from the plant.
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Wash out sprayer immediately each time spraying is completed. A hour delay may result in a clogged nozzle and a corroded tank. Do not use sprayers that have been used to apply weed control chemicals. Label and use a separate sprayer for weed control purposes only. Spray carefully and thoroughly to cover all parts of wood, leaves, and fruits.
Spray until a noticeable amount is dripping from the tree. Approximate amounts for various size fruit trees with full foliage are shown in Table 1. Alternative Means to Suppress or Control Insects and Diseases The first means of combating pest problems in fruit trees should be selecting well-adapted, resistant varieties. While few fruit varieties have been selected to resist insects, stone and pome fruits have been selected to resist diseases such as bacterial spot, black knot, cedar apple rust, fireblight, and scab.
When selecting a variety for planting be aware of the most common disease problems for your area. For instance, early-maturing peach varieties are more likely to have brown rot than late-maturing varieties, but late varieties are often damaged by peach scab. In addition to using resistant cultivars, several cultural practices may be used to combat pest problems. Disease problems are often associated with moisture usually excessive. Planting fruit trees on well-drained soils will help to reduce the risks from fireblight. Proper spacing and pruning can also improve air movement within a group of trees.
Sanitation pick up and disposal of infected or infested branches, leaves, or fruit can help reduce carryover of disease and insect problems. Foresight when planting can nearly eliminate a problem before it begins. Avoid planting stone fruits and pome fruits together. The presence of stone fruits can often encourage plum curculio problems in pome fruits, which otherwise is not a significant pest. Remove any cedars grown near apples, since they serve as alternate hosts for cedar apple rust. Do not overwater trees or apply nitrogen late in the season, because such practices can encourage lush growth creating disease problems.
Apply dormant oils or superior summer oils before the pink stage of tree development, particularly where mites, scales, or aphids have been a chronic problem. With good coverage, it is possible to kill as much as 80 percent of the eggs of European red mites; therefore, the oil should be diluted as much as possible. A two percent rate is needed at the half-green stage, but at tight cluster a one percent rate is adequate. Protecting young trees from insect injury is critical.
Because trees are not expected to bear fruit for a few years, people often plant them and then ignore them. In addition, the grower will prematurely unwind the tree wrap attached to the seedling. This material should be left on during the winter dormant period and then removed when spring growth begins. The tree wrap helps reduce problems associated with sunscald. In addition, if spring cankerworm is a threat in the area particularly on apple a three- to four-inch band of Tree Tanglefoot Pest Barrier can be added to the wrap before spring growth begins.
This sticky substance traps female cankerworms that crawl up the tree to begin laying eggs.