Semi Dwarf Research Articles

Investigation of responses of some apple (Mallus x domestica Borkh.) cultivars grafted on MM106 and M9 rootstocks to lime-induced chlorosis and oxidative stress

The response of dwarf (M9) and semi dwarf (MM106) clonal apple rootstocks and 5 apple cultivars [Granny Smith (GS), Fuji (F), Royal Gala (RG), Mondial Gala (MG) and Red Chief (RC)] grafted on these rootstocks to lime induced iron chlorosis and iron deficiency induced oxidative stress were investigated. Both rootstocks and cultivars were divided into two groups. One of the group were kept as control group. To the second group, to ensure the lime-induced chlorosis, bicarbonate (HCO3−) was applied. Both groups were grown for two years in a pot experiment. The soil used in the experiment was a clay loam calcareous soil containing 70.9gkg−1 lime. To evaluate the lime-induced chlorosis effects on both rootstocks and cultivars, accumulation of H2O2 and membrane damage (MDA, lipid peroxidation), activities of catalase (CAT, EC 1.11.1.6), superoxide dismutase (SOD, EC 1.15.1.1) and ascorbate peroxidase (APX, EC 1.11.1.11) determined. Bicarbonate treatment reduced active and total Fe and total chlorophyll concentrations, and FCR (leaf ferric chelate reductase) activity while increased the MDA, H2O2, SOD and APX activity of cultivars and rootstocks in both years. These changes and the statistical significances of individual and combined effects of treatment and cultivar or rootstocks showed great differences among the cultivars and rootstocks. So B/C rates helped us to evaluate the tolerance to lime induced chlorosis of the cultivars and rootstocks. B/C referring Fe efficiency ratio calculated as the value for the bicarbonate treatment divided by that for the control for each parameter studied used for tolerance state of cultivars and rootstocks. According to B/C ratios calculated for active and total Fe, FCR, the MG and RG grafted on both rootstocks regarded as tolerant cultivars. In addition to this, the MM106 rootstock was more tolerant than the M9 rootstock under bicarbonate applied condition giving higher B/C ratio for active and total Fe, total chlorophyll, FCR and APX but lower MDA concentrations. It can be concluded that suitable cultivar-rootstock combinations is a good strategy to overcome Fe chlorosis in apple plants grown in calcareous soils.

Rice MDU 6: A high yielding long slender grain variety

A short duration, high yielding, long slender grain rice culture, ACM 01010 was developed from Department of Plant Breeding and Genetics, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai and was released as Rice MDU 6 during 2015. ACM 01010 is a derivative of MDU5/ACM 96136. It has semi dwarf stature (95–105 cm), high tillering capacity, white long slender grain with superior grain quality. It matures in 110–115 days and it is suitable for short duration rice growing areas. This culture recorded a mean grain yield of 6118 kg/ha (9.7 per cent and 10.2 per cent increased yield over the checks, ADT 43 and ADT (R) 45 respectively) in different yield trials including MLTs and ARTs. In ART, this culture registered more than 7000 kg/ha in 29 locations out of 160 locations tested. The culture, ACM 01010, is moderately resistant to leaffolder, stem borer, GLH and WBPH under field conditions. It possesses intermediate amylose content, gelatinization temperature and soft gel consistency. It produces white long slender rice with desirable cooking quality. As raw rice, it is highly suitable for making pongal and variety rice besides it is also suitable for aval (flaked rice) and pori (parched paddy) making.

The Performance and Quality of Three Alternative Fruits in the Intermountain West Region of the United States

Adaptability and feasibility of table grape (Vitis vinifera or Vitis labrusca), asian pear (Pyrus pyrifolia), and quince (Cydonia oblonga) production under the high desert conditions of southwest Idaho in the Intermountain West region of the United States were studied. ‘Alborz’ table grape was harvested between 1 and 15 Sept. and with proper thinning, this cultivar had outstanding clusters and berries and could be a successful table grape for planting at commercial scales in warmer spots under conditions of this study. ‘Kashishi’ and ‘Autumn Royal’ were late-season cultivars and had large berries with excellent quality. ‘Ralli’, also called ‘Anahita’ in the Intermountain West, had attractive clusters and berry color, but was sensitive to frost and had poor production. ‘Princess’ grape was harvested between 5 and 30 Sept. and had poor fruit set, but berries had outstanding flavor. ‘Niitaka’ asian pear had the largest and firmest fruit with the lowest soluble solids concentration (SSC) among all tested asian pears. ‘Semi Dwarf Shinko’ asian pear had larger fruit than ‘Kikusui’ and ‘20th Century’ but smaller than ‘Niitaka’. However, ‘Kikusui’ and ‘20th Century’ had excellent fruit flavor and quality. Thus, ‘Kikusui’, ‘20th Century’, and ‘Niitaka’ asian pears can be chosen for planting under condition of this study. ‘Aromantnaya’ and ‘Rich’ quinces matured earlier and had lower fruit firmness than other cultivars. These cultivars can be planted for early market. Based on this study, ‘Van Deman’ can be chosen for fresh consumption if sweet cultivars are in demand by the market. However, ‘Rich’ and ‘Smyrna’ quinces can be chosen if fruit with large size and bright yellow color is preferred.

Response of cereals to cycocel application (Review article)

ABSTRACT- Growth retardants are natural or synthetic chemical substances which are directly applied to crops to alter some structural processes. It is expected that these alterations modify hormonal balance and growth leading to increased yield, improved crop quality or facilitated harvesting. Cycocel (CCC) or chlormequat chloride (2-chloro ethyl trimethyl ammonium chloride) as a synthetic growth retardant has been recommended for wheat since 1960s. Cycocel inhibits gibberellin biosynthesis via blocking ent-kaurene synthesis in the metabolic pathway of gibberellin production, resulting in reduced amounts of active gibberellins and consequent reduction in stem elongation. The stem shortening effect of cycocel in such cereals as wheat seems to be less important, due to release of many dwarf and semi dwarf wheat cultivars. However, using cycocel in cereal fields would be inevitable if its effect on grain yield is definite and this area needs further investigation. Importance of cycocel is greater under environmental stress conditions, and more research needs to be focused on cycocel-induced stress tolerance. In this paper, the current knowledge and possible applications of cycocel, which can be used to improve the growth and yield of cereals, have been reviewed and discussed. The role of cycocel to mitigate the harmful effects of drought and salt stresses in cereals is also examined. Furthermore, various biochemical and physiological processes leading to improved cereal crop production under the influence of cycocel are discussed.

Kultur Antera untuk Percepatan Perakitan Varietas Padi di Indonesia

<p>Rice is a staple<br />food crop in Indonesia, while the need is increasing due to<br />high rice consumption as well as population increase. The<br />problems can be solved through increase of national rice<br />production. Productivity of lowland and upland should be<br />increased intensively and other potential dry area outside<br />Java and Bali Islands should be considered for extending the<br />area of production. Recently, high yielding variety such as<br />semi dwarf variety, hybrid rice, and new plant type of rice<br />were being developed by Indonesian breeders. However,<br />new method is needed to complement conventional<br />breeding method in order to accelerate rice breeding.<br />Anther culture is one of in vitro culture techniques that can<br />be used to accelerate the obtainment of pure lines through<br />doubled-haploids (DHs) regenerated at first generation of<br />culture for less than one year. Thus, application of anther<br />culture in conventional breeding will increase the efficiency<br />of selection process as well as reducing the cost for labour,<br />land and breeder’s time. The obtainment of green plantlets<br />derived from anther culture of indica rice subspecies has<br />been improved by the addition of 1 mM putrescine into<br />induction and regeneration media. Recently, several upland<br />rice lines tolerant to abiotic stresses (i.e. low light intensity<br />and aluminum toxicity) and biotic stresses (i.e. leaf and<br />neck blast), several lowland rice/paddy lines tolerant to<br />biotic stresses (i.e. bacterial leaf blight and blast), and<br />several hybrid parental lines (i.e. male sterile, maintainer<br />and restorer) were obtained in 2-3 years from several rice<br />breeding program involving anther culture. However,<br />potential use anther culture to provide unique genetic<br />material for mapping populations for use in functional<br />genomics and molecular breeding has not been explored.<br />The results indicated that anther culture is a feasible<br />technology that can be used for accelerating rice breeding<br />program in Indonesia.</p>

Gibberellin-sensitive Rht alleles confer tolerance to heat and drought stresses in wheat at booting stage

The present study compared six near-isogenic lines from different backgrounds, varying in Rht (reduced height) alleles for gibberellin (GA) response, for heat and drought tolerance. Various temperature (day/night: 20/12 °C to 39/31 °C), and irrigation (100% field capacity and no irrigation) treatments were imposed at booting stage. Results depicted a 50% reduction in grain yield at 36.7 °C with irrigation and at 31.2 °C without irrigation. Number of grains per spike was severely reduced over 26 °C for water-stressed plants while irrigated plants did not show any significant reduction up to 34 °C. Ear numbers per pot and spikelets per spike were unaffected by irrigation till 33 °C. In Mercia, grain nitrogen, sulphur, and Hagberg falling number (HFN) were significantly higher for severe dwarfs (Rht-D1c and Rht-12), however, in Maris Widgeon, rht (tall) recorded higher nitrogen and sulphur concentration while Rht-B1b presented the maximum sedimentation of sodium dodecyl sulphate (SDS). The SDS was higher in Maris Widgeon while HFN were superior in Mercia. Conclusively, the present study demonstrated that heat and drought stresses severely reduced the grain yield while improved grain quality traits. The GA-insensitive semi dwarf Rht-B1b was the most promising genotype for grain yield and HFN under combined drought and heat stresses.

The significance of litter loss and root growth on nitrogen efficiency in normal and semi-dwarf winter oilseed rape genotypes

Winter oilseed rape (Brassica napus L.) has a high capacity for nitrogen (N) uptake, but still leaves substantial amounts of N in the soil after harvest, partly due to the N lost through shed leaves. Reduced leaf litter losses or increased N uptake might therefore be possible ways of increasing the N efficiency of winter oilseed rape. In order to determine genotype differences in litter loss and root growth, we examined biomass production, leaf litter loss, N content, yield, root distribution and root depth of winter oilseed rape, as well as soil N content, in a two-year field experiment conducted on sandy loam soils. Three genotypes were studied: a semi-dwarf (SD) hybrid and two normal hybrids. All genotypes were treated with low and high N fertilization levels of 120 and 280kgNha−1, respectively. Root growth was studied by means of minirhizotrons to 2.3m soil depth. Lost leaves contributed significantly to the N surplus left in the soil after oilseed rape. Estimations based on litter loss measurements revealed that more than 100kgNha−1 potentially could be lost during the growing season. Generally, estimated total litter loss and accumulated N loss did not differ between the studied genotypes, whereas more N was lost from the high N treatments. In spring, the nitrate (NO3−) levels throughout the soil profile were low, indicating the efficiency of oilseed rape in taking up available NO3− and reducing the risk of leaching losses during autumn and winter. The SD genotype was not found to have less leaf biomass, but had lower yields leading to lower N use efficiency (NUE) as well as lower N uptake efficiency (NUpE). Thus, the hypothesis that SD would have less biomass and consequently reduced litter loss leading to increased N efficiency was rejected. Generally, SD took up less N and tended to leave more NO3− in the upper soil layers at harvest. At maturity, roots reached at least 2.3m depth, with no significant genotype differences in depth and intensity. This implied that genotype differences in N efficiency and yield was not related to root growth differences, indicating that root growth is not the most obvious target in order to improve N efficiency of winter oilseed rape. Improving remobilization of N from the large amount of biomass lost during the growing season or decreasing the amounts of biomass produced and lost might be more obvious and effective targets.

Characterization of Gamma Ray Induced Clones in ‘Giant Cavendish’ Banana (AAA) for Morphological and Yield Contributing Traits

ABSTRACTMultiple shoot cultures of ‘Giant Cavendish’ banana cultivar were gamma ray irradiated at 10 Gy and field evaluated for their performance. Among the clones obtained, a semi dwarf variant was selected and multiplied through tissue culture. These clones along with control were established at the Experimental Farm, Kaiga, Karnataka during 2013. Morphological and yield contributing traits showed a wide range of values as compared to the control. Two clones, TBM-2 and TBM-6, were dwarf as against control and late flowering but attained maturity much before the control plants. TBM-8 variant showed substantial increase in the fruit area as against the control. Plant height exhibited negative correlation with number of suckers and fruit circumference while bunch weight showed negative correlation with days to flowering and number of fingers. Cluster analysis based on the Euclidean distances formed three distinct groups. The clones identified in this study have shown the potential of gamma rays in bringing genetic changes in agronomically important traits of banana.

Analisis Kekerabatan Genetik Kultivar Kopi Arabika Berbuah Kuning dan Berbuah Merah Berdasarkan Marka SSR

Yellow berry of Arabica coffee (AGK-1) cultivated in Garut is a local cultivar that potentially could be released as a superior variety. However, its genetic background has not been studied. Information of genetic background is one of the requirement in releasing of a new variety. The objective of this research was to analyze the genetic relationships of AGK-1 cultivar with 11 red berries Arabica coffee cultivars based on simple sequence repeats (SSR) markers to find polymorphisms and clustering. The research was carried out at the Molecular Laboratory of Indonesian Industrial and Beverage Crops Research Institute and Biology Molecular Laboratory of Indonesian Center for Agricultural Biotechnology and Genetic Resources Research and Development, from January to March 2015. These twelve Arabica coffee cultivars were obtained from Garut Regency. A total of 12 SSR primers were used to investigate the genetic relationships of the plant. The result showed that 12 SSR markers were adequate to identify the relationships among 12 Arabica coffee cultivars. The genetic clustering obtained in this study is related to plant morphology, particularly plant growth characters, such as tall, semi dwarf and dwarf. AGK-1 cultivar genetically related to ABP-2, one of red berries cultivars that originated from Brazil. Both of these cultivars have the same growing type characters (i.e. semi dwarf). AGK-1 cultivar that has yellow berry color presumably derived from an open pollinated red berries parents, mainly ABP-2 cultivar. Therefore, AGK-1 is a unique cultivar that could be released as a local superior variety.

On the 160th anniversary of Ivan V. Michurin’s birth

October 2015 marks the 160th anniversary of the birth of Ivan V. Michurin. As a scientist and plant breeder, he made a significant improvement of many varieties of fruit, berry, and flowers. He developed methods of plant breeding, promoted gardening to the north and east of Russia, including Siberia. He introduced some new berry species as Actinidia and black chokeberry and was the first in the country who used dwarf and semi dwarf stocks of apples. Michurin initiated the mass movement of fancier gardeners and horticulture experimenters in USSR who changed and significantly extended the species and geographic ranges of fruit and berry cultivation in Russia. He not only made a vast collection of species and varieties of fruit plants from around the world but also organized their involvement and widespread use in the breeding by hybridization, including interspecific crosses. He created some new artificial interspecific hybrids such as Cerapadus (cherry and bird cherry hybrid), and others. Michurin created 132 cultivars. Eleven of them are not only cultivated but also included in the “National Register of Protected Plant breeding Achievements of the Russian Federation”. Michurin, having lived a long productive life, did not come to the time when he was not only declared “the great nature transformer”, but also “appointed” creator of “Michurin’s theory”, so-called “Creative Darwinism”. However, thirty years later, scientists, though rarely, but still tried to separate his name from Lysenkoism and rehabilitate the scientist.

I. V. Michurin’S Work on Expansion of the Plant Horticulture Assortment and Improvement of Food Quality

Abstract October 2015 marks the 160th anniversary of the birth of Ivan V. Michurin. As a scientist and plant breeder, he made a significant improvement of many fruit and berry plants, and flowers. He developed methods of plant breeding, especially regarding long-distance hybridisation of fruit plants, and promoted gardening to the north and east of Russia. He introduced some new berry species, such as Actinidia and black chokeberry, and was the first in Russia to use dwarf and semi dwarf stocks of apples. Michurin initiated the mass movement of gardeners and horticulture experimenters in USSR who changed and significantly extended the assortment and areas of fruit and berries cultivation in the country. He not only brought together a representative collection of species and varieties of fruit, berry and flower plants from around the world, but also used them in breeding by hybridization, including interspecific. He created some new artificial interspecific hybrids such as Cerapadus (cherry and bird cherry tree hybrid), and others. Michurin created 132 cultivars. Eleven of them are not only cultivated, but are also included in “The State Register of Protected Plant Breeding of the Russian Federation”.

ВПЛИВ МОЗАЇЧНОГО РОЗМІЩЕННЯ СОРТІВ ОЗИМОЇ ПШЕНИЦІ НА АГРОРІЗНОМАНІТТЯ

<p>We studied the introductions of cultivars and lines of wheat soft winter wheat that are adaptive to specific physical and climatic conditions ecotopes regards forest-steppe and Polissia ecotypes by ecological and biological characteristics. We also determined their influence on formation of the diversity and productivity of agricultural ecosystems. It was established that mosaic planting pattern of winter wheat allows to get a high yield (up to 9 t/ha) and of strong and superstrong wheat (Ariivka, L 4696/96, KC-5, KC-7, KC-14, KC-22, Yuvivata 60, etc.) in comparison to monocultivar technology. Some genotypes, namely Yuvivata 60, Ariiivka KC-22, KC-7 have moderate and high resistance towards complex diseases. The mosaic planting pattern of cultivars is the important factor of increasing the diversity and strengthening the links in agricultural ecosystems.</p> <p>Based on the long-term ecological research of genetic forms of winter soft wheat in different ecotopes and comparing them by major agronomic features with cultivar-standards we selected some promising cultivars and lines. We suggested the semi dwarf, medium-grown productive, and high adaptive genotypes of wheat soft winter, like Prydesnianska, Ariiivka, Nosshpa 100, КС-5, КС-7, КС-14, КС-21, КС-22, Yuvivata 60, Zoriana Nosivska, КС-16, КС-17, Л9646/96.</p> <p><em>Key words:</em><strong><em> </em></strong><em>agrodiversity, genotype, wheat soft winter, address introduction<strong> </strong></em></p>

Genetic enhancement of Dubraj, a specialty rice through pedigree approach employing marker based selection for plant stature, aroma and grain quality

Grain quality is an important feature of the marketing strategies of the rice industry in both domestic and international markets as quality influences the market price. With the demand for aromatic rice increasing steadily, export of short grain aromatic rices having premium grain quality is a viable option as the cultivation of basmati rices is limited to a specific geographic region. However, these native premium native aromatic rices require significant improvements in yield, plant stature and response to fertilizer and as grain quality traits are complex, their retention in the recombinants is a major challenge. With the recent advances in molecular markers, selection of recombinants with desirable traits is feasible through precise tracking of the target traits. The present study reports the successful recovery of the premium grain quality traits of Dubraj in IET 21044 (L9), a derivative from Pusa 44/Dubraj cross combination using pedigree approach employing markers associated with plant stature, aroma and grain quality and stringent phenotypic selection. The validation of the superior yield potential and premium grain quality of IET 21044 in the multi location evaluation trials over a 4 year period resulted in its release thus making it the first semi dwarf, high yielding, short grain aromatic rice released in India at the national level. The study was a successful demonstration of the limitless potential of the marker technology in breeding specialty rices.

Morphological and Anatomical Investigations on Old Home x Farmingdale 333 / Pyrus elaeagrifolia in Vitro Micrografts

In this study, the possibility of creation of a specific pear rootstock combination by micrografting was investigated. Two genotypes; ‘Old Home x Farmingdale 333’ ( Pyrus communis L.) which is a clonal semi dwarf pear rootstock resistant to fireblight and pear decline, and Pyrus elaeagrifolia known as tolerant to Fe-chlorosis, salinity and drought stresses were used to obtain a clonal, semi dwarf and tolerant to the stresses pear rootstock combination. In vitro P. elaeagrifolia seedlings were used as rootstock, and in vitro shoots of ‘OH x F 333’ were used as semi dwarf interstock. Cleft grafting was applied in micrografts. Grafted seedlings were cultured on Murashige and Skoog basal medium with ½ strength of macronutrients for 8 weeks. Cultures were incubated under white fluorescent light, 16 h per day. However, complete darkness was applied for 1 or 2 weeks at the beginning of incubation for the darkness treatments. Graft take success in the control treatment was significantly higher (97.9%) than darkness treatments (90.5% and 82.5%, respectively). Ultrastructural observations with transmission electron microscope revealed that dividing cambial initials reached to 2-3 layers and new xylem and phloem elements distinctly differentiated in transversal sections of the graft union after 8 weeks of micrografts in the control and dark treatments. The results indicated that a successful graft union formation occurred. To the best of our knowledge, this is the first report of in vitro micrografting on Pyrus elaeagrifolia Pallas.

English

Wheat (Triticum aestivum L.) is the leading crops for human nutrition in Europe and in most temperate regions worldwide. This crop is demanding in nutrients, among them nitrogen (N) is absorbed in higher amounts and its efficiency of utilization can be increased with a plant biostimulant use. The objective of this work was to evaluate the influence of different N levels and ways of biostimulant application on genotypes growth of wheat, tall and semi dwarf. The experiment was carried out, in 2010, at greenhouse located in Rothamsted Research Institute, Harpenden – United Kingdom. The design was in randomized blocks, with four replications. The experiment was a 3x2x2 factorial arrangement consisting by three ways of application using a commercial biostimulant and two N levels provided by nutritive solution and two spring wheat genotypes (Green – tall and Red – semi dwarf). Isolated effect of biostimulant use was not observed on fresh matter and dry matter of aboveground part and root; however, N levels affected same variables, except root dry matter. A significant interaction between biostimulant and N was observed on dry matter of aboveground part. No significant results were found for length, surface, diameter and volume of root after biostimulant application and different N levels in Green and Red genotypes. Seed treatment and leaf spray with biostimulant did not promoted effects on N and C content in aboveground part and root for tall or dwarf wheat; on the other hand, significant differences were observed when N was applied through nutritive solution. Biostimulant application did not promoted increase on growth, N and C content of aboveground part, metabolites production and components of wheat production. Use of N promoted increase on fresh and dry matter of wheat, except dry matter of root, moreover, additions were observed in its content in aboveground part of wheat.   Key words: Semi dwarf, nutrients, plant regulator, root growth, content.&nbsp

Genomic regions and underlying candidate genes associated with coleoptile length under deep sowing conditions in a wheat RIL population

Longer coleoptile is a desirable trait in wheat for sowing under drought stress environments with moisture availability in the deeper layers of the soil. In the present study, WL711/C306 wheat RIL population and the parents were phenotyped for coleoptile length under deep sowing conditions in the field and plant growth chamber. C306, a tall traditional cultivar had longer coleoptile compared to the semi dwarf parent WL711 carrying Rht-B1b gene. The RIL population showed considerable variation, normal distribution and transgressive segregation for coleoptile length under field and controlled environment conditions. The genetic linkage map of WL711/C306 RIL population was constructed comprising of 346 markers. The total map distance was 4,526.8 cM with an averaged interval of 12.9 cM between the adjacent markers. Major novel consistent QTLs for coleoptile length were identified on 4BS, co-located with the Rht-B1b gene and on 3BS. Also major QTL was identified on chromosome 3BL for coleoptile length explaining up to 12.4 % of phenotypic variation. On comparison with the rice (Oryza sativa L.) genomic DNA sequences syntenic to wheat chromosome 4BS and 3BS, two candidate genes were identified namely gibberellin C-20 oxidase 1 and α-Expansin. These genes play a role in cell wall expansion in the young expanding tissue in the coleoptile. QTLs qCL.4B.1 and qCL.3B.1 emerge to be important for coleoptile length in the WL711/C306 RIL population suggesting their potential value for use in marker assisted selection after validation for longer coleoptile length and improved establishment.

Phenotyping and other breeding approaches for a New Green Revolution

Phenotyping and other breeding approaches for a New Green Revolution

Characterization of GA3 Insensitive Reduced Height Mutant of Emmer Wheat Var. NP200 (Triticum Dicoccum)

A γ-ray induced semi-dwarf mutant was obtained in tall emmer wheat variety NP200. The mutant was insensitive to externally applied gibberellin. An allele specific marker for dwarfing gene Rht-B1b was used to check the status of dwarfing gene in the mutant, semi dwarf and tall emmer and semi dwarf durum varieties. The primer showed amplification of Rht-B1b gene in semi dwarf durum and emmer varieties. The parent NP200 showed presence of wild type allele (Rht-B1a) with the primer pair BF-WR1. All semi dwarf emmer varieties showed a band of 237bp with primer pair BF-MR1showed presence of Rht-B1b. However, the mutant showed absence of amplification for both Rht-B1a and Rht-B1b alleles with respective primer pairs. The results indicated that the reduced height mutant carried a mutation different from the known allele Rht-B1b.

Morphological and anatomical investigations on in vitro Micrografts of OHxF 333 / Pyrus elaeagrifolia interstock / rootstock combination in pears

In this study, possibility of creating a specific interstock / rootstock combination to obtain a clonal, semi dwarf, composite pear rootstock tolerant to various stresses by micrografting was investigated. In vitro shoots of 'Old Home x Farmingdale 333' (Pyrus communis L.) which is a clonal semi dwarf pear rootstock resistant to fireblight and pear decline was used as interstock, and in vitro Pyrus elaeagrifolia Pallas seedlings known as tolerant to Fe-chlorosis, salinity and drought stresses was used as rootstock. Cleft grafting was applied in micrografts. Grafted seedlings were cultured on Murashige and Skoog basal medium with ½ strength of macronutrients for 8 weeks under white fluorescent light for 16 h day -1 . Cultures, except the control, received complete darkness either 1 or 2 weeks at the beginning of incubation. Graft take success in the control treatment was significantly higher (97.9%) than darkness treatments of 1 or 2 weeks (90.5% and 82.5%, respectively). Ultrastructural observations with transmission electron microscope revealed that dividing cambial initials reached to 2-3 layers, and new xylem and phloem elements distinctly differentiated in transverse sections of the graft union 8 weeks after micrografting in the control and darkness treatments. The results indicated a successful graft union formation.

Trunk Injection: A Discriminating Delivering System for Horticulture Crop IPM

Trunk injection technology represents an alternative delivery system to provide crop protection for horticultural crops of commercial and smallholder farmers in the developed and developing world. Field studies, laboratory bioassays, and residue profile analysis were used to determine the seasonal effectiveness of trunk injected insecticides against key apple insect pests. Insecticides formulated for trunk injection, imidacloprid, rynaxypyr, and emamectin benzoate were injected into semi dwarf Empire apple trees and evaluated for a wide range of insect pests. Imidacloprid controlled piercing and sucking pests, and emamectin benzoate controlled leaf rollers, Oriental fruit moth, and leafhoppers, and rynaxypyr controlled Oriental fruit moth and leaf rollers. The residue profiles for insecticides showed that vascular delivery was predominantly to foliage, with fruit residues far below the EPA maximum residue limits, and low to no residues detected in apple flower parts. These results suggest that trunk injection is a promising delivering system for plant protection materials for control of foliar pests, while minimizing impacts on natural enemies, eliminating spray drift, and reducing the pesticide load in the agro-ecosystem. For smallholder farmers this low-capital investment technology has the potential to significantly reduce the human health risks associated with pesticide use, while protecting high value horticultural crops from pests