Growth and flower quality of four Rosa hybrida L. cultivars in response to propagation by stenting or cutting in soilless culture

Performance of four Rosa hybrida L. cultivars (‘African Dawn’, ‘Ilios’, ‘Maroussia’ and ‘Soprano’) was evaluated. They were grown either on their own roots or grafted (stenting) onto Rosa canina L. ‘Inermis’ rootstock in a polyethylene greenhouse with hydroponics system. Parameters of plant growth and flower quality were investigated for two successive harvesting years (2005 and 2006). Results indicated that, all the cultivars were superior for most of the parameters studied when grafted onto rootstock compared to being on their own roots. Flowering stem fresh weight and diameters, flower fresh and dry weight, flower diameter and length, petal number, leaf chlorophyll content and quality index were higher in grafted plants compared to those propagated by cuttings. However, highest flowering stem length and number were observed in plants propagated by cutting, although not significant as compared with stenting method.     

Collection time,cutting age,IBA and putrescine effects on root formation in Corylus avellana L. cuttings

The effects of collection time, cutting age, indole-3-butyric acid (IBA) and putrescine application on the rooting of cuttings of Italian hazelnut cultivars ‘Tonda Gentile Romana’, ‘Tonda di Giffoni’ and ‘Nocchione’ were investigated. Samples collected during late June, late July and early September from newly formed and 1-year old part of twigs to be utilized to produce leafy cuttings, after being treated with 1000 and 2000 ppm IBA, respectively. In addition, the September cuttings were also treated, respectively, with 1000 and 2000 ppm IBA and 1600 ppm putrescine. Rooting ability was evaluated 2 months after planting for each treatment and collection time. Satisfactory rooting of hazelnut leafy cuttings was observed when collection time occurred in June and September, whereas leafy cuttings collected in July showed a limited capacity of rooting in all cultivars tested. On average, the rooting of the newly formed leafy cuttings was more than the 1-year old cuttings. Rooting was also promoted by IBA treatments, mainly in ‘Nocchione’ and ‘Tonda di Giffoni’. In contrast, young cuttings collected from ‘Tonda Gentile Romana’ in early September rooted poorly when treated with IBA alone, but showed the best rooting (∼80%) after the application of a combination of 1000 ppm IBA and 1600 ppm putrescine. The current findings confirm that putrescine can be a useful substance for increasing rooting percentage and root quality in cuttings of some hazelnut cultivars as obtained from ‘Tonda Gentile Romana’ cultivar.     

‘Swingle’ citrumelo propagation by cuttings for citrus nursery tree production or inarching

‘Swingle’ citrumelo [Citrus paradisi MacFaden × Poncirus trifoliata (L.) Raf.] has been extensively used as a rootstock in several citrus growing regions of the World, including Southern Brazil where ‘Rangpur’ lime (Citrus limonia Osbeck) is still the predominant variety despite being affected by several important pathogens. In this case, ‘Swingle’ citrumelo is used to produce nursery trees to establish new orchards or to be inarched in adult and healthy groves in order to change the rootstock. We report herein a system to produce trees on ‘Swingle’ citrumelo more rapidly by budding onto non-rooted cuttings, as well as assessing potential to rapidly multiply ‘Swingle’ through rooting of non-budded cuttings. Therefore, two potential products are described: budded trees and rooted rootstock cuttings. ‘Valencia’ sweet orange [Citrus sinensis (L.) Osbeck] was budded at different heights on cuttings derived from eight-month old rootstocks. Grafted and additional non-budded cuttings were then treated with indole-3-butyric acid (500 mg L⁻¹) or left untreated before rooting. Three types of cuttings were evaluated: softwood, semi-hardwood and hardwood. The use of nursery trees derived from pre-budded hardwood cuttings of ‘Swingle’ citrumelo is an alternative grafting method on this cultivar. Softwood cuttings with one leaf pair were considered the most adequate material for rapid multiplication of ‘Swingle’ citrumelo by cutting. This could be particularly useful for inarching production or conventional budding after transplant of cutting-derived rootstocks.     

Methods to improve the fertility of poinsettia

‘Success’ or ‘Red Splendor’ plants propagated by shoot tip culture or embryogenesis had higher pollen germination than those propagated by cutting. All clones of ‘Pepride’, ‘Peter Star’ and ‘Nobel Star’ propagated by cutting or by embryogenesis or shoot tip culture did not have viable pollen. ‘Peter Star’ mutants through mutagenesis could recover pollen viability. When both parents were propagated by tissue culture, fruit set increased compared to when one or both parents were propagated by cuttings. Furthermore, the number of the harvested seeds doubled per pollination set, when the tissue culture parents were used instead of cutting-propagation plants.     

两个柱花草品种根系构型差异及其对间作柑橘砧木实生苗磷营养的竞争

 根系构型与植物的养分吸收密切相关,可能影响植物不同个体间的养分竞争。比较了‘格 拉姆’和‘184 号’柱花草（Stylosanthes Sw.）的根系构型差异,并探讨了两者在间作条件下对柑橘砧木 红藜檬（Citrus limonia）实生苗的生长和养分吸收的影响。结果表明,‘格拉姆’和‘184 号’在单作条 件下生物量、总根长、主根长和根尖数相似,但是‘184 号’的基根角度、根系表面积、平均根直径均小 于‘格拉姆’;在与柑橘实生苗间作条件下,‘184 号’有41.4%的根系进入柑橘根区,而‘格拉姆’仅有 0.8%的根系进入柑橘根区,因此与‘184 号’间作的柑橘砧木实生苗的生物量和对磷养分的吸收均显著低 于与‘格拉姆’间作的柑橘砧木实生苗。本研究表明,与根系垂直生长型的‘格拉姆’相比,根系水平 生长型的柱花草‘184 号’不宜用于果园生草栽培,根系构型应该成为草种筛选的重要指标。     

Root development of Thuja plicata in peat-substitute rooting media

In this study we investigated the potential usefulness of different substrates produced from gorse (Ulex europaeus L.) for propagating cuttings of Thuja plicata ‘Atrovirens’. The gorse was composted by different methods, to produce four types of compost. These composts were then used as such (100% compost) or in mixes with coarse sand and pine bark compost (25% compost, 25% coarse sand and 50% pine bark compost, v/v/v) to prepare eight different substrates. The substrates were compared in cutting propagation trials carried out in a greenhouse, with a standard rooting medium consisting of 25% Sphagnum peat moss, 25% coarse sand and 50% pine bark compost (v/v/v). Cuttings were taken from a garden hedge in March 2003, and comprised shoots of the previous year's growth. The bases of the cuttings were treated with a 0.4% solution of IBA rooting hormone, then inserted into cells filled with the corresponding substrate and placed on a propagation bench. Rooting percentage and visual rooting score were determined in July. The quality of roots was evaluated, as total root length and number of root tips, in July, September and November 2003, by use of a Delta-T Scan system. The rooting success of the cuttings ranged from 75% to 90%, except when the substrate comprised the pure composted gorse, obtained after the shorter period in an enclosed composting system with addition of fertilizer and reuse of leachates. Most of the cuttings in this substrate died and only 4% of the cuttings rooted successfully. Physicochemical characteristics of this rooting medium included very high electrical conductivity, low C/N ratio and high water retention. Addition of coarse sand and pine bark compost to the composted gorse significantly increased the rooting success. The root quality variables differed depending on the substrate considered and date of harvest. The results showed that substrates made from gorse compost are of potential use as a peat substitute for propagating cuttings of T. plicata ‘Atrovirens’. The physicochemical properties of the composted gorse should be determined before its use to establish whether it can be used pure as a substrate for rooting or whether it should be mixed with other substances.     

Effect of auxin treatments,cuttings’ collection date and initial characteristics on Paeonia ‘Yang Fei Chu Yu’ cutting propagation

Paeonia ‘Yang Fei Chu Yu’ is one of the most popular and commercially valuable cultivars of herbaceous peony. The study was performed to explore propagation techniques by cuttings for the nursery industry. Results showed that the stem cuttings pretreated with 2000 mg L⁻¹ indole-3-butyric acid (IBA) in quick-dip method got the best rooting traits (rooting percentage is 86.7%, root number is 23.1 and root length per rooted cutting is 6.4 cm). Therefore pre-treatment with 2000 mg L⁻¹ IBA is recommended.     

Effect of NaCl salinity in the genotypic variation of cowpea (Vigna unguiculata) during early vegetative growth

Twenty-five genotypes of cowpea (Vigna unguiculata L. Walp.) were tested for salt-tolerance at the vegetative growth stage in pot in the greenhouse experiments at salinity levels of 0, 85, and 170 mM NaCl. Plant survival was the main criterion for classifying genotypes. Other criteria included the ion concentration (Na⁺ and Cl⁻) in root and shoot and biomass accumulation. Four local accessions (‘Paceño’, ‘Tardón’, ‘Sonorense’, and ‘Cuarenteño’), three accessions from California (‘CB46’, ‘CB27’, and ‘CB3’), and one accession from the International Institute of Tropical Agriculture (IITA) (‘IT82D-889’) survived at concentrations of both 85 and 170 mM NaCl and were classified as salt-tolerant, while ‘IT96D-666’, ‘IT89KD-288’, and ‘IT93K-734’ from IITA were classified as salt-sensitive. One local accession (‘Sesenteño’), three accessions from IITA (‘PEPH-V Wes-85’, ‘IT86D-719’, and ‘IT95K-1090-12’), and one accession from California (‘CB5’) were classified as moderately salt-tolerant. Eight accessions from IITA (‘IT96D-733’, ‘IT90K-277-2’, ‘IT91K-93-10’, ‘IT91K-118-20’, ‘IT90K-284-2’, ‘IT95K-1088-4’, ‘IT89KD-391’, and ‘IT94K-437-1’) and one from California (‘CB88’) were classified as moderately salt-sensitive. Biomass was affected by both 85 and 170 mM NaCl in all groups of genotypes, however, salt-tolerant and moderately salt-tolerant genotypes showed higher biomass than genotypes classified as moderately salt-sensitive and salt-sensitive. In all genotypes Cl⁻ concentration was higher in shoots than roots and increased as salinity increased. Similarly Na⁺ concentration increased with increasing salinity. However, in salt-tolerant and moderately salt-tolerant genotypes, Na⁺ concentration was more in roots than shoots, while in moderately salt-sensitive and salt-sensitive genotypes, Na⁺ was higher in shoots than roots.     

Adventitious root formation in Grevillea (Proteaceae), an Australian native species

Grevillea (Proteaceae) is a native Australian plant genus with high commercial value as landscape ornamentals. There has been limited research on the culture and propagation of Australian native species. The effect of indole-3-butyric acid (IBA) on the rooting of G.‘Royal Mantle’ and G.‘Coastal Dawn’ in winter, spring and summer was evaluated at University of Queensland Gatton, Southern Queensland in order to determine the rooting ability of this species in different seasons. Both Grevillea cultivars showed seasonal rooting. The more difficult-to-root G.‘Coastal Dawn’ had a reduced response to IBA application than G. ‘Royal Mantle’. Stem and leaf indole-3-acetic acid (IAA) levels were not different between cultivars, therefore rooting ability between the two cultivars does not appear to be due to the differences in endogenous IAA levels.     

Assessment of tolerance to NaCl salinity of five olive cultivars,based on growth characteristics and Na and Cl exclusion mechanisms

Changes caused by NaCl-induced salinity on several growth parameters and ions accumulation have been measured in five olive (Olea europaea L.) cultivars (‘Chemlali’, ‘Chetoui’, ‘Koroneiki’, ‘Arbequina I18’, and ‘Arbosana I43’) growing in a greenhouse in nutrient solution pot experiment. One-year-old plants were transplanted to sand–perlite (1:1) culture, and were irrigated with half-strength Hoagland nutrient solution containing NaCl at various levels (0.5, 50, 100 and 200 mM). Salinity induced significant decrease in growth parameters, but to a different extent in each cultivar. Leaf growth and total leaf area per plant were significantly affected by all salinity treatments in all studied cultivars, being ‘Arbequina I18’ the most sensitive cultivar. Leaf drop phenomenon was observed from 60 days after salt application at high salinity treatments, mainly in Arbequina I18. Contrary to leaf area, leaf thickness increased progressively during the experiment. ‘Chemlali’ developed thicker leaves at the two highest salinity treatments when compared to the other cultivars. Na⁺ and Cl⁻ concentrations were higher in roots than in shoots and leaves in most of the cultivars investigated. The effectiveness of Na⁺ exclusion mechanism in the roots differed significantly among studied cultivars, working effectively in ‘Chemlali’ (by inhibiting translocation of Na⁺ to the aerial part) and being much less efficient in ‘Arbequina I18’. Furthermore, leaf abscission can be considered as an additional tolerance mechanism of olive cultivars allowing the elimination of leaves that had accumulated Na⁺ and Cl⁻ ions. Tolerance to salinity stress was as follows: ‘Chemlali’ > ‘Chetoui’ > ‘Arbosana I43’ > ‘Koroneiki’ > ‘Arbequina I18’. This order of salt tolerance was indicated by lower reduction in plant growth parameters (shoot elongation, trunk diameter, total plant dry weight, internodes length, and total leaf area), the increase of leaf thickness, and by the effectiveness of the exclusion mechanism of Na⁺ and Cl⁻ in the root system.     

Effect of plant growth temperature on membrane lipids in strawberry (Fragaria × ananassa Duch.)

Changes in membrane lipid composition are important in the acclimation of plants. The influence of four day/night growing temperature combinations (18/12, 25/12, 25/22, and 30/22 °C) on membrane lipids of ‘Earliglow’ and ‘Kent’ strawberry (Fragaria × ananassa Duch.) were studied. The monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) were the major galactolipids in the strawberry leaves. ‘Earliglow’ contained a higher amount of galactolipids in the leaves than ‘Kent’. The major phospholipids in the strawberry leaves, roots, and fruit were phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidylglycerol (PG), and phosphatidylethanolamine (PE). PC and PE were the two predominant phospholipids in the strawberry. The leaves and fruit of ‘Earliglow’ contained higher amounts of phospholipids compared to those of ‘Kent’, whereas ‘Kent’ strawberry roots had higher phospholipids. Palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2), and α-linolenic (C18:3) acids were major fatty acids in galacto- and phospholipids of the ‘Earliglow’ and ‘Kent’ strawberry. PC is very rich in linolenic acid in leaves compared to the fruit and root tissues. PC had the highest ratio of unsaturated to saturated fatty acids among all phospholipids. There was a significant increase in the content of galactolipids (MGDG, DGDG) and phospholipids (PC, PI, PG and PE) and unsaturation of their fatty acids in the cool day/night growth temperature. Increasing day/night growth temperatures decreased MGDG/DGDG ratios. The shifts in saturation and composition of fatty acids observed with strawberry may be an adaptation response of plants to the temperature changes.     

Phenotyping vigour control capacity of new peach rootstocks by xylem vessel analysis

In peach, xylem anatomical characteristics have been shown to be related to vigour of selected rootstocks. The goal of this research was to determine if xylem characteristics of a new set of rootstocks that exhibit a range of size-controlling potential and have a different genetic background from previously examined material would also exhibit similar differences in xylem characteristics. If so, then anatomical analysis of xylem may be a useful means of predicting the vigour control capacity of selected peach rootstock genotypes. Samples of xylem tissue were taken from roots, trunks and shoots of four new rootstocks that were derived from a genetic cross between ‘Harrow Blood’ and ‘Okinawa’ peaches and compared with tissue from ‘Nemaguard’, a vigorous control. Xylem samples were sectioned and analysed by optical microscope. The number and dimensions of vessels in recently developed xylem of each rootstock were measured and compared. The more dwarfing rootstocks had fewer large vessels and more small vessels than the more vigorous rootstocks. Weighted mean vessel diameter (Wm) and calculated hydraulic conductance (K_h) differed among rootstocks: more vigorous rootstocks had higher K_h and Wm than dwarfing rootstocks. Rootstock xylem vessel dimensions varied in relation to the vigour they imparted to a common scion cultivar (‘O’Henry’). After the ‘Nemaguard’ control, ‘HBOK 50’ was the most vigorous rootstock followed by ‘HBOK 10’, ‘HBOK 32’ and ‘HBOK 27’, respectively. Thus, as was seen in previous research with a separate set of rootstocks, the vigour-control capacity of this new series of peach rootstocks was strongly related to their xylem hydraulic characteristics and it appears likely that it would be possible to use xylem anatomical characteristics of shoots or roots of young trees to pre-select for size-controlling potential in a rootstock development program.     

Yield and fruit quality of ‘Nova’ hybrid [Citrus clementina hort. ex Tanaka × (C. reticulata Blanco × C. paradisi Macfad)] and two Clementine varieties (C. clementina hort. ex Tanaka) as affected by self- and cross-pollination

Low yields of ‘Nova’ citrus hybrid are common in single variety plantings (plantings consisting of one variety) due to its sexual self-incompatibility. Self-incompatibility may be overcome by cross-pollination with other compatible varieties. Fruit quality and yield of ‘Nova’ citrus hybrid as well as of the ‘SRA63’ and ‘Marisol’ Clementines, when either they were self-pollinated in single variety plantings or each one of the two Clementine varieties was used as a pollenizer for ‘Nova’ in mixed plantings (plantings consisting of more than one variety), were investigated. The study was carried out for two successive years under the same environmental and cultural conditions using three single variety plantings (‘Nova’ × ‘Nova’, ‘SRA63’ × ‘SRA63’, ‘Marisol’ × ‘Marisol’) and two mixed plantings (‘Nova’ × ‘SRA63’, ‘Nova’ × ‘Marisol’).     

Evaluation of citrus somatic hybrids for tolerance to Phytophthora nicotianae and citrus tristeza virus

Somatic hybridization is a biotechnology tool that can be used in citrus breeding programs to produce somatic hybrids with the complete genetic combination of both parents. The goal of this work was to test the reaction of citrus somatic hybrids that may be useful as rootstocks to trunk and root infections caused by Phytophthora nicotianae van Breda de Haan (P. parasitica Dastur) and to citrus tristeza virus (CTV). The somatic hybrids evaluated were ‘Caipira’ sweet orange (Citrus sinensis L. Osbeck) + ‘Rangpur’ lime (C. limonia Osbeck), ‘Caipira’ sweet orange + ‘Cleopatra’ mandarin (C. reshni hort. ex Tanaka), ‘Caipira’ sweet orange + ‘Volkamer’ lemon (C. volkameriana V. Ten. & Pasq.), ‘Caipira’ sweet orange + rough lemon (C. jambhiri Lush.), ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange (C. aurantium L.), ‘Rangpur’ lime + ‘Sunki’ mandarin (C. sunki (Hayata) hort. ex Tanaka), ‘Ruby Blood’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, and ‘Valencia’ sweet orange + Fortunella obovata hort. ex Tanaka. For P. nicotianae trunk and root infection assays, plants of the somatic hybrids, obtained from 9-month semi-hardwood cuttings, were evaluated and compared with diploid citrus rootstock cultivars after mycelia inoculation in the trunk or spore infestation in the substrate, respectively. ‘Cleopatra’ mandarin + sour orange, ‘Rangpur’ lime + ‘Sunki’ mandarin, ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Ruby Blood’ sweet orange + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Volkamer’ lemon had less trunk rot occurrence, whereas the somatic hybrids ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange, ‘Caipira’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Rangpur’ lime were tolerant to root rot. For CTV assays, plants of the somatic hybrids along with tolerant and intolerant rootstocks were budded with a mild strain CTV-infected or healthy ‘Valencia’ sweet orange budwood. Differences in average scion shoot length indicated that the hybrids ‘Cleopatra’ mandarin + sour orange and ‘Valencia’ sweet orange + Fortunella obovata were intolerant to CTV.     

东方百合新品种‘株洲红’

 以东方百合‘Cai 74’为母本,‘索尔帮’（‘Sorbone’）为父本,采用常规杂交育种方法培育 出的切花新品种‘株洲红’,花瓣为红色带白边,柱头淡绿色,茎杆绿色带紫色斑点,对镰刀菌有很强的 抗性,适应性强,易繁殖。     

Effect of distance from early flowering pollinizers ‘Maypole’ and ‘Dolgo’ on ‘Fiji’ fruit set

An apple orchard consisting of a single cultivar under the condition of natural pollination must have suitable pollinizers such as Crab apples to ensure stable fruit production. We selected ‘Maypole’ and ‘Dolgo’ as pollinizers for the cultivar ‘Fuji’, and investigated the rate of fruit and seeds in ‘Fuji’ fruits produced by pollen of the pollinizers. We developed a method for tracing pollen flow based on the leaf color of progeny and S-RNase allele of ‘Maypole’, and on Simple Sequence Repeat (SSR) analyses of ‘Maypole’ and ‘Dolgo’. These were powerful tools for determining the distance insects (mainly Osmia cornifrons) carry pollen from the pollinizers to ‘Fuji’. Although the fruit set of ‘Fuji’ apples was not reduced with increasing distance between ‘Fuji’ apple trees and pollinizers (probably due to pollen flow from other commercial cultivars planted outside the area), the rate of ‘Fuji’ apple fruit produced by the pollen of the pollinizers decreased with increasing distance. The rate of fruit produced by the pollinizers was 84% and 77% when ‘Fuji’ was 2.5 m from ‘Maypole’ and ‘Dolgo’, respectively, and 71% and 64% when ‘Fuji’ was 5 m from ‘Maypole’ and ‘Dolgo’, respectively, but was reduced to 47% and 39% when ‘Fuji’ was 10 m from ‘Maypole’ and ‘Dolgo’, respectively. However, the spacing could cause reduced fruit size, and require extra fruit thinning for producing large fruits. It could also cause reduction of the yield for increasing the planting area of pollinizers. We recommend that pollinizers should be planted not more than 10 m from ‘Fuji’.     

The use of consecutive micrografting improves micropropagation of cherimoya (Annona cherimola Mill.) cultivars

Clonal propagation of cherimoya via micropropagation is known to be problematic and its difficulty varies depending on the cultivar used. In order to improve the micropropagation process, the use of successive micrografting was applied to three cherimoya cultivars: ‘Fino de Jete’, ‘Bonita’ and ‘Pazicas’. Grafting nodal tissue onto a rootstock derived from ‘Fino de Jete’ juvenile material improved bud sprouting significantly in all tested cultivars. Rooting of sprouted shoots from non-grafted nodal tissue was extremely poor, however, shoots derived from explants after 1–3 consecutive micrografts displayed enhanced rooting. While ‘Fino de Jete’ and ‘Bonita’ shoots displayed 50% of rooting after two micrografts, Pazicas cultivar shoots required three micrografts to reach this percentage. Rooting was maximum after three micrografts, with 70%, 60% and 50% of rooting for ‘Fino de Jete’, ‘Bonita’ and ‘Pazicas’ shoots, respectively. Rooted plantlets were mycorrhized and acclimatized under greenhouse conditions and displayed a high rate of survival (90–100%) for all cultivars, indicating that the micrografting technique could also have an effect on the acclimation of plants.     

Cultivar variation in apple peel and whole fruit phenolic composition

The quali-quantitative distribution of phenolic compounds varies considerably between apple flesh and peel, but the concentration of phenolics is substantially higher in the peel than flesh. Because the peel comprises only a small percentage of the entire fruit weight, its significance as a donor of phenolics is disputable. We assessed the contribution of the peel to the total phenolic yield of 19 apple cultivars. Calculations were based on the weight of the whole fruit and the peel (which is frequently discarded) and the concentration of individual phenolic compounds. On average, 8, 24, 32, 50 and 66% of chlorogenic acid, (+)-catechin, (−)-epicatechin, phloridzin, and rutin, respectively, were present in the peel, which constitutes about 6–8% of the whole apple weight. With the exception of chlorogenic acid, 50% or more, on average, of the above phenolics were present in the peel of ‘Granny Smith’, ‘Idared’, ‘Red Rome’, ‘Jonamac’ and ‘Gloster’ apples; the highest percentage was found in ‘Starking Delicious’ apple peel (82%). The lowest peel contribution to total phenolic content per whole apple ranged between 26 and 29% and was observed in ‘Pilot’, ‘McIntosh’ and ‘Prima’ apples. Presented results may be useful for further investigations of the relationship between phenolics and agronomical parameters or future selection of apple genotypes having improved nutritional quality when consumed as fresh or as processed apple products.     

Piriformospora indica promotes adventitious root formation in cuttings

Adventitious root formation in excised plant shoots is a crucial process in the vegetative propagation of many plant species, and insufficient rooting causes substantial losses in the propagation industry. Based on the various physiological effects on whole plants described for the basidiomycete Piriformospora indica, it was hypothesized that inoculation of the substrate with this endophyte should promote the generation and growth of adventitious roots in cuttings. Inoculation experiments were conducted to study the effects of P. indica on adventitious rooting in three plant species. Inoculation with P. indica dramatically enhanced the number and length of the adventitious roots in pelargonium and poinsettia. Root colonization parameters suggest that the interaction between the endophyte and cuttings had already occurred before physical contact. In contrast, petunia showed no rooting response to P. indica inoculation. Very fast root formation in this plant indicates that a minimum time period for the fungus–plant interaction is required for establishment of a promoting effect. P. indica-based biotechnology is proposed as a new tool for improving plant propagation systems of plant species or cultivars with low to moderate capacity of adventitious root formation.