Lateral Shoot Formation Research Articles

Synthesis of 6-benzylaminopurine and the study of biological active properties of cotton C-6424 plants

6-Benzylaminopurine is a broad-spectrum plant growth regulator, able to rejuvenate plants, bring plants out of dormancy, cause the formation of lateral shoots and root shoots, stimulates the formation of chlorophyll and positively affects photosynthesis, making the leaf darker and greener, stronger, in many crops are able, with out-of-root processing of green fruits and berries, to somewhat postpone the ripening time in favor of size and weight. The variety of heterocyclic compounds is due to the possibility of variations: the number and nature of heteroatoms in a molecule, the ring size, the degree of unsaturation, which determines the presence or absence of aromaticity, and the possibility of the existence of condensed structures. The main attention in the methodological development is given to the most common methods of synthesis and the chemical properties of the main classes of aromatic heterocyclic structures. This choice is due to the fact that it is aromatic heterocycles that exhibit specific chemical properties inherent only to these classes of compounds, while the properties of saturated structures or unsaturated non-aromatic heterocycles, as a rule, are similar to their acyclic analogs.

Reguladores de crescimento e adubos minerais efeito nos indicadores morfométricos e nas qualidades decorativas das variedades Zinnia Elegans

Abstract Growth regulators had a significant effect on the morphometric parameters of graceful zinnia, among which the most effective was Epin-extra. Being treated twice with epibrassinolide, zinnia plants had a more saturated color range. Zircon (a drug from the group of hydroxycinnamic acids), as it turned out, had a lesser effect on morphometric parameters than Epin-extra. The Mechta (in English translation as Dream). Further in the text this name will be used) variety turned out to be more resistant to unfavorable weather conditions and in comparison with the Oranzhevyy korol’ (in English translation as Orange King). Further in the text this name will be used variety, it more easily tolerated recurrent cold and droughts during the growing season. In addition, the Dream variety turned out to be more even in height and in the formation of lateral flowering shoots, which is important to create ornamental flower compositions. The use of growth regulators and mineral fertilizers increased zinnia visual perception. Among the varieties, the variety Dream had the most preferable decorative qualities.

К ВОПРОСУ О МОРФОЛОГИИ ГЕНЕРАТИВНЫХ РАСТЕНИЙ MYRICA GALE L.

The distribution of Myrica gale on the coast of the Gulf of Finland is confined to regularly flooded coastal habitats, characterized by milder environmental conditions compared to the uplands and under the residual influence of the Gulf Stream. In Russia, M. gale is located on the northeastern border of the range. The study of the features of the species that contribute to the dispersal in the northern direction, and the properties of the environment that prevent such dispersal, is always of great interest. Growth in colder conditions in comparison with other members of the family, mainly inhabitants of the tropical and subtropical areas, affected the formation of such adaptations as deciduousness, changes in the structure of flowers and bark, as well as the presence of a large number of protective leaf organs. Their quantitative and qualitative analysis made it possible to establish the presence of 4 lignified parchment-like scales that do not fall completely and 6 membranous with partially lignified tops scales that stretch out while unfolding. An attempt was made for the first time to analyze the spatial structure of the shoots of the species. A sympodial growth of shoots and the phenomenon of acrotonia, as well as a spiral formation of lateral shoots, were established. In the structure of the mature generative branch of M. gale there were identified 3 types of shoots: long growth, medium and short, and also their leaf series were analyzed.
 Leaf series of short and medium shoots are characterized by significant asymmetry compared to leaf series of long shoots and are incomplete. The curves were constructed on the basis of such characteristics of leaf organs as their total number, length along the central vein, including the petioles (if they are presented), and internode lengths. A large number of rudiments of leaf organs determines the gradual formation of the buds, and the imperfection of the structure of the scales reflects the weak protective ability of these organs. Both features indicate the deep ancientness of the species and the difficulty in adapting to cold environmental conditions. Mature generative branches of M. gale are similar in habit to small trees, which is of particular interest in the context of modeling possible directions of adaptation during the spread of species of subtropical origin to more northern regions.

Inhibition of lateral shoot formation by RNA interference and chemically induced mutations to genes expressed in the axillary meristem of Nicotiana tabacum L.

BackgroundLateral branches vigorously proliferate in tobacco after the topping of the inflorescence portions of stems for the maturation of the leaves to be harvested. Therefore, tobacco varieties with inhibited lateral shoot formation are highly desired by tobacco farmers.ResultsGenetic inhibition of lateral shoot formation was attempted in tobacco. Two groups of genes were examined by RNA interference. The first group comprised homologs of the genes mediating lateral shoot formation in other plants, whereas the second group included genes highly expressed in axillary bud primordial stages. Although “primary” lateral shoots that grew after the plants were topped off when flower buds emerged were unaffected, the growth of “secondary” lateral shoots, which were detected on the abaxial side of the primary lateral shoot base, was significantly suppressed in the knock-down lines of NtLs, NtBl1, NtREV, VE7, and VE12. Chemically induced mutations to NtLs, NtBl1, and NtREV similarly inhibited the development of secondary and “tertiary” lateral shoots, but not primary lateral shoots. The mutations to NtLs and NtBl1 were incorporated into an elite variety by backcrossing. The agronomic characteristics of the backcross lines were examined in field trials conducted in commercial tobacco production regions. The lines were generally suitable for tobacco leaf production and may be useful as new tobacco varieties.ConclusionThe suppressed expression of NtLs, NtBl1, NtREV, VE7, or VE12 inhibited the development of only the secondary and tertiary lateral shoots in tobacco. The mutant lines may benefit tobacco farmers by minimizing the work required to remove secondary and tertiary lateral shoots that emerge when farmers are harvesting leaves, which is a labor-intensive process.

Molecular mechanism of lateral bud differentiation of Pinus massoniana based on high-throughput sequencing

Knot-free timber cultivation is an important goal of forest breeding, and lateral shoots affect yield and stem shape of tree. The purpose of this study was to analyze the molecular mechanism of lateral bud development by removing the apical dominance of Pinus massoniana young seedlings through transcriptome sequencing and identify key genes involved in lateral bud development. We analyzed hormone contents and transcriptome data for removal of apical dominant of lateral buds as well as apical and lateral buds of normal development ones. Data were analyzed using an comprehensive approach of pathway- and gene-set enrichment analysis, Mapman visualization tool, and gene expression analysis. Our results showed that the contents of auxin (IAA), Zea and strigolactone (SL) in lateral buds significantly increased after removal of apical dominance, while abscisic acid (ABA) decreased. Gibberellin (GA) metabolism, cytokinin (CK), jasmonic acid, zeatin pathway-related genes positively regulated lateral bud development, ABA metabolism-related genes basically negatively regulated lateral bud differentiation, auxin, ethylene, SLs were positive and negative regulation, while only A small number of genes of SA and BRASSINOSTEROID, such as TGA and TCH4, were involved in lateral bud development. In addition, it was speculated that transcription factors such as WRKY, TCP, MYB, HSP, AuxIAA, and AP2 played important roles in the development of lateral buds. In summary, our results provided a better understanding of lateral bud differentiation and lateral shoot formation of P. massoniana from transcriptome level. It provided a basis for molecular characteristics of side branch formation of other timber forests, and contributed to knot-free breeding of forest trees.

Effect of growth regulators and mineral fertilizers on seed productivity and decorative qual-ities of zinnia

Growth regulators had a significant effect on seed productivity of zinnia elegans, among which the most effective was epin-extra. With a two-fold treatment of zinnia plants with epibrassinolide, the increase in the collection of seeds compared to the control was 36%. The preparation from the group of hydroxycinnamic acids zircon was less productive. The increase in the collection of zinnia seeds from double spraying with zircon was 15%. The application of mineral fertilizers in a dose of N24P24K24, on average, over three years provided an additional collection of zinnia seeds by 20–35%. Analysis of variance of the data on the seed productivity of zinnia showed that a significant interaction was noted between the factors of the use of mineral fertilizers and growth regulators, i.e. the influence of one factor intensified the effect of the other. Among the varieties of zinnia, the graceful variety Mechta turned out to be more resistant to unfavorable weather conditions and, in comparison with the Orange King variety, tolerated recurrent cold and droughts more easily during the growing season. In addition, the Mechta cultivar turned out to be more even in height and in the formation of lateral flowering shoots, which is important when used in ornamental flower compositions.

Interspecific grafting between Gossypium hirsutum, G. barbadense and G. herbaceum lines

Seedling grafting could provide additional crop improvement strategies for cotton. However, there existed limited studies on interspecific grafting and approaches. Four different grafting approaches were developed and compared between lines representing three of the four cultivated cotton species G. hirsutum, G. barbadense and G. herbaceum. Grafting approaches of this study focused on the cotyledon node and cotyledon leaves retained on scions, rootstocks, without cotyledon node and cotyledon leaves on scions and rootstocks or halved cotyledon node and single cotyledon leaf on scions and rootstocks. Evaluations of the grafting approaches were made by comparing survival and growth rate during the second and fifth weeks after transplantation, respectively. The formation of any lateral shoots at the grafted sites were studied in two of four grafting approaches in the first and the second year during flowering stage. DNA alterations due to grafting were investigated using microsatellite markers. There were no statistically significant differences between grafts and their control in survival rate and locus specific DNA alteration. Growth rate and lateral shoot formation, on the other hand, were different among grafting types and grafts. We concluded that grafting without cotyledon node and cotyledon leaves on rootstocks, and with cotyledon node but without cotyledon leaves on scions were easy to perform and suitable for interspecific cotton grafting. Results suggested that grafting seedlings and allowing time to heal graft wounds prior to spring transplanting or double cropping is suitable for wheat–cotton intercropping to prevent late or early chilling damage associated with seed sowing or conventional transplanting of susceptible seedlings. Furthermore, the rapid and consistent wound healing in seedling grafts along with lateral shoot formation occurring in two of four grafting approaches make them a suitable approach to investigate possible genetic and epigenetic movement between scions and rootstocks, especially across species.

Розвиток рослин огірка посівного бджолозапильного гібриду Янос f1 залежно від рівня мінерального живлення

Розвиток рослин огірка посівного бджолозапильного гібриду Янос f1 залежно від рівня мінерального живлення

Identifikasi Awal Perbedaan Karakter Morfofisiologi Antar Empat Kultivar Kopi Arabika

<em>Arabica coffee is a perennial crop hence it has a long selection cycle. Therefore, efforts to shorten the selection process is necessary, such as at seedling stage. This study aims to identify morpho-physiological characters variability among Arabica coffee cultivars at seedling stage. The experiment was conducted at Pakuwon Experimental Garden of Indonesian Industrial and Beverage Crops Research Institute, Sukabumi, from January to October 2017. Seeds collected from open pollinated trees of four arabica coffee cultivars (Ateng Super, P88, Gayo 1, and Gayo 2) were then sown on seedbed and newly-emerged cotyledonous seedlings were transferred immediately into polyethylene bag (polybag). Seedlings were arranged in randomized complete block with 5 replications, each consisted of 10 seedlings of each cultivar. Morpho-physiological characters observed and analyzed were shoot (plant height, lateral shoot formation, number of internodes, internode length, stem diameter, shoot’s dry weight); leaves (number of leaves, leaf length, leaf width, L/W ratio, leaf area, stomata density , chlorophyll content); and root (root length, number of primary roots, root volume, root’s dry weight, root/shoot ratio). The result showed value of genetic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), and broad sense heritability (h<sup>2</sup><sub>bs</sub>) of plant height characters are classified as high, each of which is 21.66%; 23.66%; and 0.84, respectively. The characters of the stem length and leaf width showed high h<sup>2</sup><sub>bs</sub> value (0.97 and 0.67 respectively), while the KKG and KKF values were classified as moderate (19.60% and 19.88%, respectively and 10.71% and 13.10%, respectively). Those three characters could be utilized as distincitive markers of the four Arabica coffee cultivars.</em>

Alpha monofluoro substitution at C5 in homotyphasterol enhances shoot production and multiplication rate of in vitro-grown marubakaido apple rootstock shoots

KEY MESSAGE: 5 fluoro-typhasterol is more effective than the most potent natural brassinosteroid, brassinolide, towards stimulation of shoot production in the marubakaido apple rootstock. Brassinosteroids (BRs) comprise a class of low-abundance plant steroids required for normal plant growth. Here we demonstrate that treatment of in vitro-grown shoots of the marubakaido apple rootstock with 2.5 µg per shoot of 5α-monofluoro homotyphasterol (5F-HTY), a synthetic derivative of the natural BR homotyphasterol (HTY), resulted in significant enhancement in the formation of primary lateral shoots. This treatment also resulted in increased length of primary lateral shoots and main shoots. This growth-stimulatory effect led to a significant increase in the multiplication rate for the rootstock. In contrast to what was found for 5F-HTY, neither HTY nor the synthetic derivative 3α-monofluoro homotyphasterol (3F-HTY) were able to significantly stimulate shoot formation. HTY and 3F-HTY were not able to stimulate primary lateral shoot elongation as well. However, both HTY and 3F-HTY were able to significantly stimulate main shoot elongation. The 5F-HTY-driven enhancement of the multiplication rate described here demonstrates the potential of this compound to improve micropropagation techniques, not only for the marubakaido apple rootstock.

Ontogeny of Lobelia dortmanna genets in lake ecosystems

Lobelia dortmanna L. is one of the few rare, slowly growing relic plants occupying areas of the littoral zone of water bodies with low nutrient content and subject to wave action. Even in such difficult conditions, this plant successfully passes its entire life cycle, actively blossoms and fruits. That is why the peculiar features of the individual development of this plant in various geographical conditions is a matter of great interest. For the first time, this study considers in detail the ontogeny of the genet of L. dortmanna in oligotrophic lakes of Tver oblast. Detailed characteristics of the following age stages of individuals are given: resting seeds, seedlings, juvenile, young and adult vegetative, latent generative, middle-aged and old generative and quasisenile plants. It is shown that the transition to the juvenile age stage occurs at the end of the first year of life, the virginile age stage lasts two years, and the generative stage of development occurs in the fourth year of life. The change in the growth pattern of the rosette main shoot of Lobelia, from orthotropic to anisotropic, occurs in the second year of life. The establishment and further development of the generative organs of the plant and associated change in the growth of the main shoot from monopodial to simpodial occurs in the fourth year of life. At the same time, the branching of the main shoot begins by formation in the axils of the uppermost assimilating leaves (the last in front of the apical inflorescence) – 1–2 lateral rosette shoots. These are future ramets (vegetative diasporas), which ensure, in the future, the vegetative reproduction of the individual and spread to new territories. Taking into account that in lakes of Tver oblast, Lobelia groupings form dense aggregated clusters on the bottom, the transition of individuals to a quasisenile age state (in the fifth year of life) enables them to rejuvenate and survive after the death of the maternal shoot. The formation and further development of rosette lateral shoots allows the plant to re-occupy the territory via vegetative or seed propagation. Complete morphological disintegration (vegetative reproduction) occurs in the fifth year of life. The genets’ ontogeny is completed by the formation of a compact clone from the detached lateral rosette shoots.

Phenological growth stages of hemp (Cannabis sativa L.): codification and description according to the BBCH scale

The current paper discusses the characteristics of principal growth stages of hemp (Canabis sativa), provides a brief description of these stages and of the coding system according to the BBCH scale. The growing season of hemp is divided into nine principal growth stages: germination and sprouting (0), leaf development (1), formation of lateral shoots (2), stem elongation (3), inflorescence emergence (5), flowering (6), development of fruit (7), ripening of fruit (8) and senescence (9). The principal growth stages are subdivided into secondary stages based on their main distinctive features. The classification system of hemp growth stages presented in the paper is designed for hemp growers and researchers, including plant breeders, physiologists, entomologists and other agricultural producers. Using the uniform coding system of the phenological stages of hemp is a valuable tool to ensure a more efficient planning and implementation of crop and soil management practices and techniques.

Carbon allocation to growth and storage in two evergreen species of contrasting successional status.

A prevailing hypothesis in forest succession is that shade-tolerant species grow more slowly than shade-intolerant species, across light conditions, because they prioritize carbon (C) allocation to storage. We examined this hypothesis in a confamilial pair of species, including one of the fastest-growing tree species in the world (Eucalyptus globulus) and a shade-tolerant, slow-growing species (Luma apiculata). Seedlings were subjected to one out of four combinations of light (high vs. low) and initial defoliation (90% defoliated vs. nondefoliated) for four months. Growth, C storage concentration in different organs, leaf shedding, and lateral shoot formation were measured at the end of the experiment. Eucalyptus globulus grew faster than L. apiculata in high light, but not in low light. Both species had lower C storage concentration in low than in high light, but similar C storage concentrations in each light condition. Defoliation had no effect on C storage, except in the case of the old leaves of both species, which showed lower C storage levels in response to defoliation. Across treatments, leaf shedding was 96% higher in E. globulus than in L. apiculata while, in contrast, lateral shoot formation was 87% higher in L. apiculata. In low light, E. globulus prioritized C storage instead of growth, whereas L. apiculata prioritized growth and lateral branching. Our results suggest that shade tolerance depends on efficient light capture rather than C conservation traits.

Growth and phenology of three Andean potato varieties (Solanum tuberosum L.) under water stress

The water-deficit stress has a negative effect on the growth and development of plants, reducing the yield of crops. This study evaluated the effect of a water deficit on the growth and phenology of potato (Solanum tuberosum L.) varieties Diacol Capiro, Pastusa Suprema and Esmeralda. Plants that were starting tuberization were subjected to a water deficit by suspension of irrigation until reaching a foliar water potential of -2.0 MPa; later the plants were re-irrigated and recovered. The water deficit decreased the flowering time in 'Diacol Capiro', the development of leaves and maturation of fruits in 'Esmeralda' and the development of leaves and formation of lateral shoots in 'Pastusa Suprema'. In the three varieties, the water deficit did not induce a significant reduction in the stem length, the number of leaves per stem and per site or the number of main stems per site. The plants demonstrated responses related to escape and evasion mechanisms during the water deficit through the adjustment of the metabolism in order to reduce the duration of the phenological stages. The duration of the biological cycle for the three varieties was 148 days, with a requirement of 1,850 GDD. There were no differences in the potential yield, probably due to the short duration of the stress period. The three varieties demonstrated plasticity when modifying the phenology in response to the drought period.

Effects of interstock length on sylleptic shoot formation, growth and yield in apple

Bu çalışmada 2003-2010 yılları arasında, MM106 anacı üzerinde 15 ve 30 cm uzunluğundaki M9 ara anacının Golden Delicious ve Granny Smith elma çeşitlerinde fidanın dallanması üzerine etkisi ile vegetatif büyüme ile toplam verim üzerine etkisi belirlenmiştir. Sonuçlar, ara anaç yüksekliğinin artması ile her iki çeşitte fidan ve ağaç gelişiminin önemli ölçüde azaldığını ancak yan dallanmanın arttığını göstermiştir. En uzun ağaç boyu Golden Delicious ve Granny Smith çeşitlerinin kontrol grubunda sırasıyla 176.5 - 186.5 cm olarak, en kısa ağaç boyu ise aynı çeşitlerde 30 cm’lik ara anaç yüksekliğinde sırasıyla 147.5 cm ve 162.6 cm olarak ölçülmüştür. Kontrolde yan dal oluşumu meydana gelmezken, yan dal sayısı 30 cm’lik ara anaç yüksekliğinde 3.67 (Golden Delicious) ve 5.33 (Granny Smith) bulunmuştur. En yüksek toplam verim, 30 cm’lik ara anaç yüksekliğinden 21.77 kg ağaç-1 (Golden Delicious) ve 19.18 kg ağaç-1 (Granny Smith) elde edilmiştir. Sonuçlar, bodur M9 ara anacının özellikle sürdürülebilir ve organik elma yetiştiriciliği sistemlerinde büyümeyi azaltıcı, dallanma ve erken meyveye yatmayı ise teşvik etme potansiyelinin bulunduğunu göstermektedir.

Induction of Lateral Branching in Sweet Cherry (Prunus avium L. cvs. “Siah Mashhad” & “Dovomras”) Trees in Nursery

This study was carried out in two independent experiments on one year old sweet cherry (Prunus avium L. cvs. “Siah Mashhad” and “Dovomras”) nursery trees with the main purpose of improving lateral shoot formation and increasing the quality of trees. In the first experiment, heading treatments (0, 40, 60 and 80 cm above ground) and in the second experiment, Arbolin treatments (0, 5, 15, 25 mL·L-1) was investigated. Trees were treated with foliar sprays of Arbolin in 2 times at 7-days intervals in mid-June. At the end of the growing season, the tree quality was measured on the basis of their diameter and height of trees, number, length and angels of lateral shoots. A factorial experiment was laid out in a completely randomized block design with 3 replications where each plot contained 10 trees. Results showed that all of the treatments increased the number of laterals in comparison with the control. The cultivars had different response to the treatments. Heading in 60 cm was the best treatment for improving total number of lateral shoots. The result of second experiment showed that there were significant differences between cultivars and Arbolin treatments. The number of lateral shoots enhanced with application of higher concentrations and repeated Arbolin treatments in both cultivars. Arbolin treatments had more significant effect on the number and length of lateral shoots than heading treatments.

The effect of different bioregulators on lateral shoot formation in maiden apple trees

Abstract One-year-old Malus domestica Borkh. ‘Boskoop’ and ‘Mutsu’ nursery trees on M.9 rootstock were treated with foliar sprays of different BA + GA3 mixtures (450 + 450 mg dm-3 or 780 + 120 mg dm-3) or BA + GA4+7 combinations (450 + 450 or 330 + 570 mg dm-3). Both cultivars showed strong apical dominance; however, increased branching potential was observed following the use of exogenous growth regulators. All of the investigated branching agents revealed a high effectiveness, yet only after one treatment. Environmental factors played a major role in the induction of sylleptic shoot formation, especially in the case of ‘Boskoop’. In the case of ‘Boskoop’, the branching effect was correlated with several vegetative growth properties (tree height, trunk diameter), while for ‘Mutsu’, a different branching pattern was found with no correlations ascertained. No tree injuries were observed following the use of a chemical branching agent.

The tomato (Solanum lycopersicum cv. Micro-Tom) natural genetic variation Rg1 and the DELLA mutant procera control the competence necessary to form adventitious roots and shoots.

Despite the wide use of plant regeneration for biotechnological purposes, the signals that allow cells to become competent to assume different fates remain largely unknown. Here, it is demonstrated that the Regeneration1 (Rg1) allele, a natural genetic variation from the tomato wild relative Solanum peruvianum, increases the capacity to form both roots and shoots in vitro; and that the gibberellin constitutive mutant procera (pro) presented the opposite phenotype, reducing organogenesis on either root-inducing medium (RIM) or shoot-inducing medium (SIM). Mutants showing alterations in the formation of specific organs in vitro were the auxin low-sensitivity diageotropica (dgt), the lateral suppresser (ls), and the KNOX-overexpressing Mouse ears (Me). dgt failed to form roots on RIM, Me increased shoot formation on SIM, and the high capacity for in vitro shoot formation of ls contrasted with its recalcitrance to form axillary meristems. Interestingly, Rg1 rescued the in vitro organ formation capacity in proRg1 and dgtRg1 double mutants and the ex vitro low lateral shoot formation in pro and ls. Such epistatic interactions were also confirmed in gene expression and histological analyses conducted in the single and double mutants. Although Me phenocopied the high shoot formation of Rg1 on SIM, it failed to increase rooting on RIM and to rescue the non-branching phenotype of ls. Taken together, these results suggest REGENERATION1 and the DELLA mutant PROCERA as controlling a common competence to assume distinct cell fates, rather than the specific induction of adventitious roots or shoots, which is controlled by DIAGEOTROPICA and MOUSE EARS, respectively.

The effects of heading and benzyladenine applications on branching of apple (cvs. ‘Red Delicious’ and ‘Golden Delicious’) trees in nursery

This study was carried out in two independent experiments on one year old apple (Malus domestica cvs. ‘Red Delicious’ and ‘Golden Delicious’) nursery trees with the main purposes of improving lateral shoot formation and increasing the quality of trees. In the first experiment, the effect of different heading treatments (0, 40, 60 and 80 cm above ground) and in the second experiment, benzyladenine (BA) treatments (0, 200, 400, 600 mgL-1) was investigated. Trees were treated with foliar sprays of BA thrice at 7-day intervals in mid-June at the end of the growing season. The tree quality was measured on the basis of their diameter and height of trees, number and length of lateral shoots. A factorial experiment was laid out in a completely randomized block design with 3 replications where each replication was comprised of 10 trees. The results showed that the heading treatments had significant effects on the branching of apple trees. Heading in 60 cm was the best treatment for improving the total number of lateral shoots. The results of second experiment showed that there were significant differences between cultivars and BA treatments. In both experiments, ‘Red Delicious’ had better response to treatments than ‘Golden Delicious’ cultivar. BA treatments had more significant effect on the number and length of lateral shoots than heading treatments. Repeated BA treatments induced lateral shoots more than a single treatment. Key words: ‘Golden Delicious’, height, lateral shoot, ‘Red Delicious’, tree quality.

Effects of grafting height of MM106 rootstock on growth, lateral shoot formation and yield in apple trees

SummaryBetween 2004 and 2008, the effects of different grafting heights on sylleptic shoots were tested in the apple (Malus domestica Borkh.) cultivars ‘Granny Smith’ and ‘Gloster’, and cumulative fruit yields were evaluated. MM106 apple rootstocks were grafted 10, 20, 40, or 60 cm above soil level in August 2004. The results showed that an increased grafting height significantly decreased tree height in both cultivars. The tallest and shortest trees were observed at grafting heights of 10 cm (153.0 and 170.0 cm) and 60 cm (141.3 and 143.5 cm) in ‘Granny Smith’ and ‘Gloster’, respectively.Among the various grafting heights tested, 60 cm in ‘Granny Smith’ and 20 cm in ‘Gloster’ gave the largest stem diameters (17.6 mm and 16.8 mm, respectively). The number of lateral shoots increased significantly with increased grafting height in both cultivars. The largest numbers of lateral shoots in ‘Granny Smith’ (10.75) and ‘Gloster’ (2.00) were obtained from a grafting height of 60 cm, while 2.55 and zero lateral shoots occurred at 10 cm grafting height in ‘Granny Smith’ and ‘Gloster’, respectively. Shoot lengths decreased significantly by increasing the grafting height. Grafting heights of 10 cm and 60 cm resulted in the tallest and shortest shoots in both cultivars. Cumulative fruit yields were significantly affected by grafting height in both cultivars. The highest yield was found for a 60 cm grafting height in both ‘Granny Smith’ (11.295 kg tree–1) and ‘Gloster’ (4.818 kg tree–1).The results of this study suggest that grafting heights of 40 cm and 60 cm have the potential to promote branching and early bearing for apple fruit production in sustainable and organic agricultural systems.