Columnar Trees Research Articles

Characterization of Transcriptional Differences Between Columnar and Standard Apple Trees Using RNA-Seq

The columnar apple tree is a valuable resource for genetic improvement of cultivated apples due to its special architecture. To identify genes involved in the columnar architecture, expression profiles of newly developing shoots of standard and columnar trees from a segregating population of “Fuji” × “Telamon” have been analyzed using the new generation of high-throughput RNA-Seq technology. Following Blast analysis against Nr, SwissProt, KEGG, and COG databases, a total of 69,558 unigene annotations have been identified. Among them, more than 80.68% and 79.87% clean reads of Apple-Co and Apple-St samples, respectively, have been mapped to reference apple genome. Interestingly, 57% of genes were covered with more than 50% clean reads. Moreover, 1,252 and 1,443 unigenes from Apple-Co and Apple-St tissues, respectively, had alternative splicing sites. Among these, 614 and 666 were alternative 3′ splice sites and the most abundant, followed by alternative 5′ splice sites, while exon skipping sites were the least frequent. In addition, 13,142 and 13,334 novel transcript units were identified form Apple-Co and Apple-St samples, respectively. Moreover, analysis of RPKM (reads per kilobase per million reads) values found that expression of 5,237 unigenes differed by more than twofold. Among these, 1,359 were enriched in 232 metabolic pathways based on KEGG database annotation, and 2,233 were enriched in biological regulation, cellular process, etc. pathways based on GO functional annotation, and 287 unigenes were related with apple architecture. Among the 287 unigenes, 31 unigenes mapped to chromosome 10 of apple genome, and 25 unigenes were GRAS transcription factor, which were suggested to play an important role in architecture formation of columnar apple trees. Taking together, this study provided a theoretical basis for further enriching gene resources of important agronomic traits of fruit trees and for understanding the formation mechanism of columnar apple trees.

Morphological differences of vessels in the secondary xylem of columnar and standard apple trees

La longitud, dimension y tipo de los vasos en el xilema secundario de arboles de manzana estandar y columnar se estudia - ron por el metodo de aislamiento y microfotografia. Los resultados mostraron que las celulas de los vasos del xilema del tallo fueron reticuladas y agujereadas en las manzanas estandar y columnar. La mayoria de las paredes del fondo fueron simples platos perforados. Comparado con los arboles de manzana columnar, los arboles de manzana estandar mostraron mas celulas anormales en las celulas de los vasos del xilema. El diametro promedio de las celulas de los vasos del xilema de tallos fue significativamente mas amplio en la manzana columnar (43.27 μ m) que en la manzana estandar (32.64 μ m). La longitud de las celulas de los vasos del xilema de tallos no tuvo un modelo consistente en las manzanas estandar y columnar. Los resul - tados de este estudio contribuirian a explicar porque los arboles de manzana columnar tienen mayores tasas fotosinteticas y relaciones de utilizacion de energia luminica que los arboles de manzana es - tandar. Estas caracteristicas deben haber contribuido a una floracion y fructificacion mas temprana en los arboles de manzana columnar

Morphological traits of phytomers and shoots in the first year of growth as markers for predicting apple tree canopy architecture

With 1 figure and 7 tablesAbstractApple tree canopy architecture is very important for productivity, fruit quality and ripening. Our objective was to evaluate inheritance traits of an apple tree canopy and to identify morphological phytomer or shoot parameters, which could be used as a marker for selection of apple trees with desired canopy architecture. Crosses between apple trees with different canopy architecture using top‐cross scheme were performed. Combining ability of parental cultivars and clones was evaluated. Progeny of columnar and spur ideotype apple trees will have the shortest internodes according to general combining ability effects. Offspring of standard and weeping apple trees will have moderate and long internodes. Data show that apple phytomer parameters, such as internode length and lamina angle to shoot, are inherited and related to future plant canopy architecture. These phytomer traits are easily detected in the first year of growth of apple hybrid. It was shown that short internode is directly related to columnar tree canopy, and high lamina angle to shoot in the juvenile phase is a morphological marker of weeping apple tree canopy.

Tree growth and some other characteristics of new columnar apple cultivars bred in Holovousy, Czech Republic

Several characteristics related to tree growth, their fruitage and resistance against scab and powdery mildew were assessed during 2007–2008 on five new cultivars in comparison with the ancestral McIntosh Wijcik, in which 4 out of 5 had their pedigree. In several plots established between 1998 and 2006, the trees, which were on different rootstocks predominantly planted in spacing 4 × 0.5 m, were grown as vertical cordons practically without any pruning or shaping. Besides the first years after the planting these columnar trees generated very limited side branching. The cultivars mutually differ in tree vigour, spurring density, and size of fruiting spurs. Mean annual prolongation of central axes in the case of the trees on vigorous rootstocks varied within 30.8–57.5 cm, however, on M 9 rootstock it was distinctly shorter (23.4–34.1 cm). Beyond cultivar and rootstock the length of the annual prolongation was also significantly influenced by fruit set level. Trees of the Kordona cultivar were generally the most vigorous while those of Pidi were the weakest. The biennial pattern of bearing observed to an extent on nearly all the cultivars was connected with tendency to over-crop the trees. The highest annual yield equal to 10.3 kg was generated on trees of Kordona on MM 106, which corresponds to a total harvest of 25.7 t/ha. Cultivars Herald and Slendera possessed combined resistance both to scab and powdery mildew, whereas Kordona and Cumulus were resistant only to scab, but were in different degrees susceptible to mildew.

Analysis of the ‘A72’ Peach Tree Growth Habit and Its Inheritance in Progeny Obtained from Crosses of ‘A72’ with Columnar Peach Trees

Since the first report of the ‘A72’ semidwarf peach [Prunus persica (L.) Batsch] tree in 1975, no new information has become available on this genotype. We evaluated the growth habit and verified the inheritance of ‘A72’ in a population of 220 progeny derived from self-pollination. Detailed tree and branch measurements revealed a unique forked-branch (FBR) character of the ‘A72’ (Nn) phenotype. The progeny segregated into 1 NN:2 Nn:1 nn. NN trees were indistinguishable from standard peach trees, Nn were FBR, and nn were dwarf. Hybrids between ‘A72’ and columnar (brbr) peach trees confirmed that FBR is inherited as a monogenic trait that appears to express incomplete dominance. ‘A72’ (Nn) trees were later blooming than sibling NN trees. The relationship (linkage or pleiotropy) between the growth habit of ‘A72’ and late bloom is not known. The structure of ‘A72’ trees presents new opportunities to breeder/geneticists, physiologists, and horticulturists to further explore the plasticity of peach tree growth and architecture that can be achieved through breeding. Applications of the ‘A72’ growth habit for commercial fruit production and as an ornamental, particularly in the dwarf form (nn) and in combination with the columnar tree (brbr) form, present opportunities that await exploration.

Red apple juice: breeding, drink- and growing technology for the development of a new, innovative product.

A ‘Wijcik’-called, natural mutation of the 'McIntosh' kind of apple, with red pulp and light red juice, was discovered in the 50ies. Its fruits growing very close to the trunk characterize it. The crown of these columnar tree is about 3-4 meters long, with a diameter about 20-30 cm. The advantage of this kind of tree is that tree-cut is mostly unnecessary, tunnel-spraying equipment can be used and harvesting maybe fully mechanised. This new product, combined with the new kind of cultivation, requires for new technologies for growing and harvesting. While labour becomes the limiting factor of production, handwork is impractical and thus a new method for mechanical harvesting in columnar apple growing is needed. For this purpose, a mechanical grape harvester, adapted for these special apple trees by modifying the harvesting head, is used to prove the suitability of this technique in pomiculture. Furthermore, tunnel-spraying equipment is adapted for this purpose and tested as well, in order to enable drift and loss reduction in plant protection.

Study of tree architecture of apple (Malus × domestica Borkh.) by QTL analysis of growth traits

Apple tree architecture is naturally very diverse, but for fruit production, certain tree habits are more desirable than others. Here we describe the results of a QTL analysis performed to study the genetic control of growth traits in apple. This was carried out on the progeny of a cross between two apple cultivars of contrasting tree architectures. “Telamon” has a columnar tree form and “Braeburn” has a more standard, “normal” growth habit. The growth traits were measured on the F 1 seedlings of the Telamon × Braeburn population for two consecutive years of growth on own roots and for the first year of growth on M9 rootstock. QTL analysis was carried out using either the Kruskal–Wallis method or the Multiple QTL Method. For all but one growth characteristic, significant QTLs were detected. A major cluster of QTLs was located in the Co gene region of “Telamon”, confirming the major influence of the Co gene on tree architecture, although this influence changed as the plant material aged and was generally more pronounced for rootstock-grown plants. Additional QTL results suggest the occurrence of genes with pleiotropic effects on tree architecture. The observed QTL instability over different years and for different root systems indicates that the genetic control of tree architecture is largely influenced by environmental factors and probably changes as the tree matures. Finally, a major influence of the root system on all the traits determining tree architecture was clearly demonstrated.

Responses to Scenes with Spreading, Rounded, and Conical Tree Forms

Research has shown that people typically give high aesthetic preference ratings to trees with spreading canopies, similar to those found on the African savanna. If the savanna hypothesis is correct, people likely will have strong emotional responses to such trees as well. In this study, preferences and emotional responses of 206 participants to viewing scenes with different tree forms and urban elements were examined. Slide images of spreading, rounded, or columnar trees, or inanimate objects in two urban scenes were created. As expected, participants found scenes with trees more attractive than scenes with inanimate objects, and they rated spreading trees more attractive than rounded or columnar trees. Participants reported more positive emotions when viewing trees compared to inanimate objects, and they were happier when viewing spreading trees compared with other tree forms. These results are consistent with the savanna hypothesis, with emotional responses relating to preferences for trees with spreading forms.

Development of RAPD and SCAR markers linked to the Co gene conferring columnar growth habit in apple (Malus pumila Mill.)

SummaryThe columnar growth habit in apple is desirable for labour-saving cultivation, since columnar trees can be planted very close together with no staking and little pruning. Bulked segregant analysis and randomly amplified polymorphic DNA (RAPD) analysis were performed to identify DNA markers linked to the columnar growth habit (Co) using an F1 progeny of standard ‘Fuji’ (coco)× columnar ‘Tuscan’ (Coco). Of the 432 10-mer or 12-mer primers examined, only one clear and repeatable polymorphic product appeared to be linked to the Co gene. The RAPD marker, designated as WB82670, was located 1.8.cM from the Co locus, closer than markers reported previously for this gene. Based on the sequencing data of this product, two oligonucleotides of 28 bases containing the original 12-mer RAPD primer sequence (ATCCCACATTCC) were synthesized and used as sequence-specific primers for DNA amplification. All genotypes positive for WB82670 including ‘Tuscan’ gave a single product of 670 bp, while all WB82670-negative genotypes failed to generate any product. This sequence characterized amplified region marker, designated as SCB82670, linked to the Co gene will be useful to select for columnar growth habit at an early stage of apple breeding programmes.

TESTING A MICROSATELLITE MARKER FOR SELECTION OF COLUMNAR GROWTH HABIT IN PEACH [PRUNUS PERSICA (L.) BATSCH

Tree fruit breeding requires large numbers of seedlings in the field for selection. These trees occupy large land areas and are expensive to maintain. Most seedlings are discarded, thus the investment in these trees is lost. Selection in the greenhouse would spare much of this expense. Marker-assisted selection offers this possibility. A microsatellite marker was tested for selection of columnar (also termed “pillar or “broomy”) growth habit (brbr). Columnar trees are being tested for highdensity production systems. Seventy-five genotypes were used for this study. These included compact (CT), dwarf (DW), standard (ST), and 2 sources of columnar; showy-flowered (SFP) with small, melting-, white-flesh fruit, and non-showy flowered (NSP) with large, non-melting-, yellow-flesh fruit. The microsatellite marker pchgms1 has been previously assigned a position 12.5 cM from the br locus in SFP trees. Using pchgms1 in this study, 2 fragments were obtained. One fragment was present only in SFP trees, the other was present in all other trees, including NSP. Hybrids of SFP with NSP and with all other growth habits contained both fragments. These results indicate that trees heterozygous for SFP can be selected, using pchgms1. At the seedling stage, prior to field planting, ST seedlings (BrBr) cannot be readily distinguished from trees heterozygous for br based on morphological traits. The efficiency of breeding programs developing brbr (columnar) or heterozygous Brbr (upright) trees could be improved by discarding ST trees prior to field planting. Using pchgms1, trees carrying the columnar trait, homozygous or heterozygous, could be selected from crosses using SFP as a parent. While this study demonstrates the usefulness of a satellite marker for selecting columnar growth habit in peach, the AFRS breeding program is utilizing NSP for cultivar development because of its higher fruit quality. The development of a microsatellite marker specifically for NSP or for both SFP and NSP sources of columnar growth habit is underway.

Simulation of within-tree and between-tree shading of direct radiation in a forest canopy: effect of crown shape and sun elevation

The pattern of momentary within-tree and between-tree shading of foliage in direct radiation flux was simulated in fully-stocked model stands with a Poisson distribution of trees. The canopies were composed of umbrella-like (crown-height/crown-radius, or H/ R = 3), average ( H/ R = 8) or columnar ( H/ R = 20) tree crowns. The momentary radiation-extinction probability was calculated for a large number of points (10 6−10 7 points per ha) within the canopy. The radiation-attenuation rate depended on the projected leaf-area density within the crown. At solar elevations of 5° and 45°, columnar crowns had the most between-tree and the least within-tree shading, while at a high sun elevation (85°) the same was true for umbrella-like crowns. At low and medium sun elevations (5° and 45°) the crown shape had a rather small effect on the total shading of foliage. At a high sun elevation, flat, horizontally extended crowns were clearly best-illuminated, because both within-tree and between-tree shadings were low.