Terminal Cuttings Research Articles

1-Methylcyclopropene Improves Ethylene Tolerance of Unrooted Herbaceous Cuttings but Delays Adventitious Root Development in Angelonia, Calibrachoa, Impatiens, Portulaca, Sutera, and Verbena Cultivars

Knowing which herbaceous taxa are ethylene sensitive and managing exposure of unrooted terminal stem cuttings to ethylene in those taxa are critical for maintaining high-quality propagules that root readily. Of 59 taxa surveyed, freshly harvested terminal cuttings of Begonia hybrid ‘Snowcap’, Lantana camara L. ‘Patriot Sunbeam’, and Portulaca oleracea L. ‘Fairytales Sleeping Beauty’ were sensitive to exogenous application of 1 μL·L−1 ethylene, as demonstrated by leaf abscission within 24 hours of treatment. Exposure to 1-methylcyclopropene (1-MCP) at 700 μL·L−1 for 4 hours before ethylene treatment prevented ethylene injury in these species/cultivars. Exposing unrooted cuttings to 700 μL·L−1 1-MCP induced significant endogenous ethylene biosynthesis in terminal cuttings of the five taxa tested: Euphorbia pulcherrima Willd. ex Klotzsch ‘Visions of Grandeur’, Impatiens hawkeri W. Bull ‘Sonic Red’, Pelargonium peltatum (L.) L’Hérit. ‘Mandarin’, Pelargonium ×hortorum Bailey (pro sp.) [inquinans × zonale] ‘Rocky Mountain White’, and Petunia ×hybrida Vilm. ‘Suncatcher Coral Prism’. Exogenous 1 μL·L−1 ethylene improved adventitious rooting in two cultivars: Begonia hybrid Anita Louise and Fuchsia triphylla L. Honeysuckle. Other trials showed that 1-MCP exposure reduced root number and length of P. ×hortorum ‘Kardino’ and delayed adventitious rooting in all six cultivars tested: Angelonia angustifolia Benth. ‘Carita Lavender’, Calibrachoa ×hybrida Llave & Lex. ‘Terra Cotta’, I. hawkeri ‘Sonic Red’, P. oleracea ‘Fairytales Sleeping Beauty’, Sutera cordata Kuntze ‘Abunda Blue Improved’, and Verbena ×hybrida Groenl. & Ruempl. ‘Aztec Wild Rose’. Subsequent exposure to 1 μL·L−1 ethylene partially mitigated the negative effects on rooting from exposing cuttings to 1-MCP.

Effect of humic acid on sprouting and rooting of stem cuttings of dalberiga sissoo roxb.

The present study was conducted at FRC, Mandar (Ranchi), Jharkhand to study effect of the humic acid on sprouting and behavior of Dalbergia sissoo. The extracted humic acid was acidic in nature and available N and P content was lower than commercial HA (Humicil). Branch cuttings were treated with different concentrations of extracted HA in different months and its responses were recorded. Both sprouting and rooting were varied significantly with time, position and humic acid concentrations. The 0.08% extracted HA shown highest sprouting and survival per cent during August and September whereas 0.02% HA produced maximum sprouts and survival percent during December month. The highest percentage of both sprout and survival of basal and terminal cuttings were found at 0.04% and 0.08% HA, respectively during February. Extracted HA promotes root growth and root nodule in the clonal seedlings at 0.06% HA. Shoot growth and biomass of clonal seedlings were augmented by HA at 0.08% HA.

Regulation of flower production in chrysanthemum (Chrysanthemum morifoliumRamat.) through photoperiodic treatments

Studies were conducted on the effect of photoperiodic treatments on regulation of flower production in two standard varieties of chrysanthemum viz. Thai Ching queen and Purnima. The plants raised through rooting of terminal cuttings were maintained under long day (LD) condition from 15 August to 15 February by interrupting the night period daily for two hours from 10 pm to 12 am by placing the pots under CFL lamps (23 Watt). These plants were periodically shifted to natural day length (ND) condition from September to February. Time of flower production in both the varieties was significantly affected by photoperiod treatments. Transferring plants from ND to natural short day length (SD) condition in September and October decreased number of days to produce flowers as compared to those maintained continuously under ND condition w.e.f. August. The plants transferred from LD to ND condition in the month of November and December took longer to reach commercial flower harvesting stage where as those transferred to ND condition in the months of January and February produced flowers in minimum number of days, respectively. Flower production in two varieties under study could be extended to end of April but the post harvest quality of flowers produced decreased due to rise in temperature in March and April.

Propagación asexual de azul de mata (<i>justicia tinctoria</i>(OERST.) d. n. gibson, fam. acanthaceae) por medio de estacas

Se evaluó el efecto de dosis de ácido indolbutírico (0, 500, 1000 o 1500 ppm), la posición de donde se toma la estaca (basal, medial o terminal), el tamaño de la estaca (6, 10 o 14 cm), la ausencia o presencia de hojas, y el tipo de sustrato (arena de río, fibra de coco o carbón de granza de arroz), sobre el enraizamiento de estacas de azul de mata bajo ambiente protegido. Las variables evaluadas fueron el porcentaje de brotación y de enraizamiento, número de brotes, cantidad y longitud de raíces. Las estacas terminales presentaron los mayores valores para todas las variables, excepto porcentaje de enraizamiento: mayor número de brotes (17,5), longitud (0,17) y cantidad de raíces (0,65) que las estacas mediales y basales, lo que estaría asociado a una mayor velocidad de enraizamiento. Las dosis de AIB 1000 y 1500 ppm indujeron una mayor cantidad de raíces por estaca (8,40 y 9,24 respectivamente) que las dosis menores. Hubo mayor porcentaje de enraizamiento con 1000 ppm de AIB (69%) que sin ese compuesto (41%). Al utilizar estacas sin hojas aumentó la magnitud de cada una de esas variables. Con arena se obtuvo una mayor brotación aérea (96%), enraizamiento (92%) y longitud de raíz (5,1 cm) que con los otros sustratos. Las estacas de 14 cm presentaron consistentemente, mayor número de brotes (3,71), raíces más largas (3,56 cm) y en mayor número (10,71) que las de 10 y 6 cm.

Comparison of Plant Propagation Efficiency under Hydroponic / Soilless Culture and Traditional / Soil Culture Systems

The work aimed to investigate plant propagation efficiency of hydroponic/soilless culture system compared to traditional/soil culture system, and the possibility of its application in the production of different ornamental plants. For the comparison, cuttings of the most important ficus species, F. penjamina and F. Hawaii, were cultivated under the two systems in two separated experiments. Three effective factors including plant species, cutting type and growth regulators type were studied under the two culture systems. Terminal and intermediate cuttings of both ficus species were cultivated hydroponically in water or traditionally in an equal mixture of sand and peat moss. Both media were supplemented with 50 ppm of (IAA), 3-indole acetic acid, (IBA), indole-3-butyric acid or (NAA), 1- naphthyl acetic acid solutions besides control treatment without any growth regulator. To investigate the application of hydroponic system in the production of different plant genera, cuttings of Schefflera and Ficus were cultivated under hydroponic system feeding by 50 ppm of IAA, IBA, NAA or water for control treatment. The studied factors had important roles in the propagation of plants via cuttings under the two culture systems. F. penjamina responded better than F. hawaii. Terminal cuttings were better under traditional system but intermediate cuttings were better under hydroponic system. Treatment of cuttings by growth regulators was essential under both systems, and IAA was the best one. A difference was also found between the two studied culture systems where traditional system was better for survival of cuttings however, hydroponic system was better for rooting and growth of cuttings. The application of hydroponic system on scheffelera proved the importance of plant type factor. The reported work showed the differences between the two culture systems, and the possibility of their application for the production of different plants. The obtained results could be of great importance for the production of plants at commercial scale by any culture system.

Micropropagation of Achillea millefolium L. on half-strength ms medium and direct rooting and acclimatization of microshoots in hydroponic culture

The aim of this study was to determine the possibility of micropropagation of the medicinal plant A. millefolium on half-strength MS medium and ex vitro rooting and acclimatization of the obtained microshoots in hydroculture in order to establish an efficient production method. Two explant types were used: basal and terminal cuttings, and better results were achieved when terminal cuttings were used. The development of shoots in the multiplication phase was successful with a regeneration percentage of 100%. Ex vitro rooting in a modified Hoagland nutrient solution was successful (83%), but the percentage of in vitro rooting on half-strength MS medium without hormones was higher (95%). However, bearing in mind that mass production of A. millefolium is more efficient when the phase of in vitro rooting is excluded, this method could be recommended for commercial propagation of this medicinal plant. It is necessary to conduct additional research in order to optimize the composition, EC and pH value of the hydroponic nutrient solution.

山竹外植体消毒技术研究

为了建立山竹组培快繁体系，以山竹叶片、茎段为外植体材料，开展了3种消毒剂不同消毒时间的单因素试验，在此基础上，设计L16(44)正交试验研究了外植体类型、75%酒精、10%次氯酸钠及0.1%升汞的消毒时间对消毒效果的影响，结果表明：叶片为外植体材料建议只采用0.1%升汞进行消毒处理，处理时间10~15 min；茎尖为最适宜的外植体材料，消毒方式为75%酒精消毒90 s，再用0.1%升汞消毒15 min或10%次氯酸钠消毒18 min，再用0.1%升汞消毒10 min。以茎段为外植体材料，消毒效果不佳。 In order to develop rapid propagation system，the various concentrations of the disinfectants were prepared for single factor experiments taking mangosteen leaves and stem cuttings as the materials. Based on the results, an orthogonal experiment with L16(44) array of four factors and four levels, namely explants, NaClO disinfection time and HgCl2 disinfection time, was conducted. The results showed that a 10 - 15 min’s disinfection time of 0.1% HgCl2 was strongly proposed when the leaves were used as explants. Stem tip explants were much better than leaves and terminal cuttings in view of its lower rate of contamination and relatively higher survival rate. A concentration of 75% alcohol for 90 s followed by a 15 min’s disinfection time of 0.1% HgCl2, or a concentration 10% NaClO for 18 min followed by a 10 min’s disinfection time of 0.1% HgCl2 was the corresponding sterilization method. It showed a poor disinfection effect when stem cuttings were used as explants.

A comparative study to improve rooting of English lavender stems cuttings

An experiment was conducted to compare the ability of two bacteria strains from Agrobacterium rhizogenes (DSM30200 and A4), yeast extract (0.5, 1 and 2 g/L) and indole butyric acid (IBA) (50, 100 and 150 mg/L) on rooting of the terminal cuttings of Lavandula angustifolia L plant. A .rhizogenes strains were more effective than most of the other treatments in increasing rooting percentage, roots number and increase of cuttings length except using IBA at 100 and 150 mg/L, as no significant differences were found between them. In contrast, the controls cuttings and cuttings treated with yeast at higher concentrations produced the lowest rooting percentage. Same trend treatments which showed higher rooting characteristics also recorded higher percentage of total carbohydrates, phenol and N percentage. On commercial scale use of two examined strains of A. rhizogenes for rooting of terminal cuttings of L. angustifolia can reduce the use of synthetic auxins like IBA. Key words: Agrobacterium, yeast extract, IBA, lavender, stem cutting.

Cutting Type and IBA Treatment Duration Affect <i>Teucrium fruticans</i> Adventitious Root Quality

Root development of stem cuttings of Silver Germander (Teucrium fruticans) was investigated in relation to cutting type and indole-3-butyric acid (IBA) treatment. Terminal cuttings of a clone grown in Sicily were trimmed to three types: terminal cuttings with apex (TWA), terminal cuttings without apex (TWOA) or sub-terminal cuttings (ST). To verify the cutting response to exogenous auxin, cuttings were dipped to a 2.0 cm depth in a 0.5% indole-3-butyric acid solution for 0, 5 or 7 minutes. Overall percent survival was 97 to 98%. Rooting percent, root number and root length were affected by cutting type and indole-3-butyric acid treatment. In general, TWA cuttings demonstrated a higher capacity to form roots than cuttings without apex (TWOA and ST cuttings). In absence of indole-3-butyric acid treatment, TWA and ST cuttings gave higher rooting percentages than TWOA cuttings. Exposing cuttings to indole-3-butyric acid improved percent rooting, number of roots per cutting and root length. The best results in terms of rooting percentage and root number per cuttings were obtained with TWA cuttings in combination with 7 min indole-3-butyric acid basal dip. However, cuttings taken farther down the stem, such as sub-terminal cuttings gave satisfactory rooting performance as well. We suggest that the use of all cutting types tested associated to indole-3-butyric acid basal dip for 5 or 7 min may be beneficial to propagators wishing to produce T. fruticans rooted cuttings with well-developed root system.

Effect of various combinations of nitrogen, phosphorus and potash on enhancing the flowering time in Chrysanthemum (Chrysanthemum morifolium)

The experiment was conducted at Hazara Agriculture Research Station Abbottabad, Pakistan during 2010-11 to evaluate the impact of various N, P, K combinations (Control, Nitrogen (N), Phosphorus (P), Potash (K), N+P, N+K, P+K and N+P+K) on plant height, number of branches, suckers, leaves, flowers per plant, leaf area, days to flowering, blooming period, flower size and flower fresh weight. The experiment was conducted as a Completely Randomized Block Design with 8 treatments replicated 4 times. Terminal cuttings were individually planted in 7 cm plastic pots on 10th June. Plants were transplanted to 28 cm pots on 10th July. Application of fertilizer with (N+P+K) combination was significantly better with plant height (63.9 cm), maximum leaf area (131.6 cm 2 ), less days (116) to flower, more number of flowers (32), maximum blooming period (38 days), larger flower size (6.3 cm) and flower fresh weight (4.4 g). Untreated chrysanthemum plants had least plant height (46.5 cm), number of branches (7) per plant, number of leaves (47) per plant, leaf area (94.2 cm 2 ), number of flowers (15) per plant, blooming period (35 days), flower size (4.5 cm) and fresh weight (3.3 g). Treatment of plants with (N+P+K) combination alone gave flowering after 116 days from planting in 7 cm pots and produced flowers on 4th October which was earlier than the normal season.

Effects of the time of cuttings collection and IBA concentration on the rooting of softwood cuttings from elite trees of Cornelian cherry (Cornus mas L.) in Belgrade area

In this study, the effect of concentration of indole-3-butyric acid (IBA) (powder dip), cutting type as well as the time of taking cuttings on the rooting of softwood cuttings of cornelian cherry was examined. Four types of cuttings were used: basal cuttings, terminal cuttings, basal cuttings with 2-year-old wood and terminal cuttings with 2-year-old wood. The obtained results showed that IBA concentration, cutting type and time of collecting have significant effect on rooting. The best results were obtained using 1% IBA and cuttings collected in the second term (in mid-July) had a higher rooting percentage. Terminal cuttings treated with 1% IBA (powder dip) should be used for optimum results. In that case the rooting percentage was very high (over 90%) in both terms of cuttings collection.

Growth of Chrysanthemum Cultivars as Affected by Silicon Source and Application Method

The effect of different silicon (Si) sources and methods of application on the growth of two chrysanthemum cultivars grown in a soilless substrate was investigated. Rooted terminal cuttings of Dendranthema grandiflorum ‘Lemmon Eye’ and ‘Pink Eye’ were transplanted into pots containing a coir-based substrate. A nutrient solution containing 0 or 50 mg?L -1 Si from calcium silicate (CaSiO₃), potassium silicate (K₂SiO₃) or sodium silicate (Na₂SiO₃) was supplied once a day through an ebb-and-flood sub irrigation system. A foliar spray of 0 or 50 mg?L -1 Si was applied twice a week. Cultivar and application method had a significant effect on plant height. Cultivar, application method, and Si source had a significant effect on plant width. Of the three Si sources studied, K₂SiO₃ was found to be the best for the increasing number of flowers, followed by CaSiO₃ and Na2SiO₃. In both the cultivars, sub irrigational supply of Si developed necrotic lesions in the older leaves at the beginning of the flowering stage as compared to the control and foliar spray of Si. Cultivar, application method, Si source, and their interactions had significant influence on leaf tissue concentrations of calcium (Ca), potassium (K), phosphorus (P), magnesium (Mg), sulfur (S), sodium (Na), boron (B), iron (Fe), and zinc (Zn). The addition of Si to the nutrient solution decreased leaf tissue concentrations of Ca, Mg, S, Na, B, Cu, Fe, and Mn in both cultivars. The greatest Si concentration in leaf tissue was found in ‘Lemmon Eye’ (1420 μg?g -1 ) and ‘Pink Eye’ (1683 μg?g-1) when K₂SiO₃ was applied through a sub irrigation system and by foliar spray, respectively.

Effect of species, cutting position and exogenous rooting substances on rooting of honeybush (Cyclopia spp.) cuttings

Effect of the cutting position, terminal and subterminal, and rooting substance on the rooting of cuttings of two Cyclopia species (Cyclopia genistoides and C. intermedia) taken in winter, spring or summer was studied under controlled glasshouse conditions. Cuttings taken in summer, irrespective of the species, rooted better than cuttings taken either in winter or spring. This poor rooting performance of cuttings in winter and spring resulted in no significant treatment effects and for this reason only results of cuttings taken in summer are discussed. Cyclopia genistoides rooted significantly better than C. intermedia as measured by rooting percentage, number of roots per cutting, length of longest root and mean root length. Terminal cuttings from C. genistoides also increased rooting percentage and number of roots compared to subterminal cuttings, but not so in C. intermedia. Longest roots were produced by terminal cuttings irrespective of species. Treatment with different exogenous rooting substances as a main factor did not have any significant effect on rooting in this study.

Effect of an organic plant fertiliser on the establishment of rooted cuttings of two species of Cyclopia (honeybush)

The effect of different application rates of an organic plant fertiliser (Nitrosol®) on the establishment and early growth of rooted cuttings of Cyclopia (Fabaceae) species was evaluated. Rooted terminal and subterminal cuttings of C. intermedia and C. genistoides were transplanted into pots (576 cm3) and treated with Nitrosol® fertiliser at application rates of 0 (control), 1.67 and 3.33 ml Nitrosol® l-1 water. To enhance the formation of nodules the cuttings were inoculated with symbiotic Rhizobium bacteria. The different species differ in their response to the fertiliser treatment, with C. genistoides showing a larger response than C. intermedia, especially at the higher application rate of 3.33 ml Nitrosol® l-1 water. This study therefore suggests that Nitrosol® fertiliser applications can be recommended to enhance the establishment of rooted cuttings of Cyclopia species, but optimum application rates may differ between species. Although a significant specie × cutting position interaction was shown with regard to plant height and number of shoots per plant, cutting position in general did not have an effect on the establisbment of the species used in this study.

Silicon supply through the subirrigation system affects growth of three chrysanthemum cultivars

The effect of silicon (Si) treatment on the growth of three chrysanthemum cultivars grown in a soilless substrate was evaluated. Rooted terminal cuttings of Dendranthema grandiflorum ‘Gaya Pink’, ‘Lemmon Tree’, and ‘White Angel’ were transplanted into pots containing a coir-based substrate. A nutrient solution containing 0, 50, or 100 mg·L−1 Si from potassium silicate was supplied once a day through a subirrigation system. Application of Si significantly increased the plant height, stem diameter, number of branches, and chlorophyll content, as compared to the control. Addition of Si at 50 and 100 mg·L−1 into the nutrient solution significantly enhanced number and size of flowers, respectively. When plants were treated with Si necrotic lesions appeared in the older leaves at the beginning of the flowering stage. Concentrations of phosphorus (P), sulfur (S), calcium (Ca), magnesium (Mg), and zinc (Zn) in the leaves increased, while the concentrations of potassium (K), boron (B), copper (Cu), iron (Fe), and manganese (Mn) decreased with the increasing Si concentration in the nutrient solution. Among the cultivars, ‘Lemmon Tree’ contained the greatest Si concentration (1364 μg·g−1) followed by ‘Gaya Pink’ (1158 μg·g−1) and ‘White Angel’ (586 μg·g−1).

Cotton gin trash compost in the substrate reduces the daminozide spray dose needed to produce compact potted chrysanthemum

Research was conducted to evaluate cotton gin trash compost (CGC) as a peat substitute in the growth medium of compact potted chrysanthemum, and its possible interaction with the plant growth retardant butanedioic acid mono-(2,2- dimethylhydrazide) (daminozide) applied to control plant size. Rooted terminal cuttings of Dendranthema grandiflora Tzvelev. var. Yoko Ono were potted in an 1 peat: 1 perlite (by volume) medium or in an 1 CGC: 1 peat: 2 perlite (by volume) medium and their foliage was sprayed three times with an aqueous solution of 0, 2000, 2500, 3000 or 3500mgl−1 daminozide. The replacement of half of the peat amount in the growth medium with CGC had a restrictive effect on shoot elongation, retarding mainly the internodal length, effect similar to that induced by daminozide. Plants grown in the CGC medium and not treated with daminozide had similar shoot lengths as plants in the peat-perlite medium sprayed with 2000 or 2500mgl−1 daminozide. The combination of CGC with the lowest daminozide concentration used (2000mgl−1) induced shoot growth retardation similar to that induced by the highest concentrations (3000–3500mgl−1) of daminozide in the peat-perlite medium. Leaf size was reduced by CGC as by the higher doses of daminozide, while flower head size was not affected. Both, daminozide and CGC, induced an acceleration of flowering, but the final flower head number was not affected. CGC decreased shoot, flower head and peduncle dry weights and increased root dry weight. At planting day, CGC medium had higher pH, EC, bulk density and total solids and lower total porosity and EAW (easily available water) compared to peat-perlite medium; it also held less water in saturation and drained faster. At the end of the experiment the two media had similar pH and EC values. Substitution of 50% peat with CGC in the commonly used medium for potted chrysanthemum commercial cultivation resulted in a reduction of at least 33% of the dose of daminozide necessary to meet the needs of the market for compact plants, with multiple economic and environmental benefits.

규산염 종류와 적용방법이 칼랑코에 '페페루'의 생육에 미치는 영향

The effect of different source silicon (, , and ) and their application methods (foliar application and subirrigation) on the growth of potted kalanchoe was investigated. Rooted terminal cuttings of Kalanchoe blossfeldiana 'Peperu' were transplanted into 10.5 cm plastic pots containing a commercial growing medium. Then, a nutrient solution, containing 0 or Si as , , or and adjusted to EC 1.4- and pH 6.0, was supplied through subirrigation along with the nutrient solution or by a foliar application. Plants were grown in a glasshouse under a mean temperature of and RH of 70-80%. After 12 weeks of cultivation, plant growth characteristics and leaf tissue contents of P, K, Ca, Mg, Na, S, and Si were measured. Both subirrigational supply and foliar application of Si decreased the plant height and flower stem length. However, the plant condition in the foliar application resulted in disease-like soft rot on the leaf. Among three silicon sources tested, supplied through a subirrigation system increased shoot tissue contents of Si and chlorophyll as compared to the or treatment. Shoot tissue contents of Ca, K, and Na increased when the plant was supplied with , , and , respectively. Subirrigational supply of and decreased the shoot tissue contents of Ca and Mg, and K and Ca, respectively. Therefore, supplied through a subirrigation system could improve plant quality of kalanchoe 'Peperu' making compact potted plants.

A COMPARATIVE STUDY ON PLANTING CUCUMBER HYBRIDS BY USING CUTTINGS AND CONVENTIONAL METHOD

The experiment was carried out during the two successive seasons of 2008/2009 and 2009/2010 on cucumber plants (Cucumis sativus L.) Hesham hybrid, grown under greenhouse condition. Two types of cuttings, i.e., terminal and basal, were taken from pruning the side shoots of cucumber hybrid to encourage the development of cuttings instead of the expensive seeds of the hybrids. The results indicated that terminal cuttings were superior to the basal cuttings for obtaining the highest values of survival percentage, root length, fresh and dry weight of the produced seedlings. To have a full understanding about the vegetative growth habits of cutting culture and their total yield in comparison to those of conventional plants (seed sowing), both types of seedlings produced from cuttings (terminal and basal) and seed propagation were planted at the same time in a greenhouse. The results summarized that conventional plant method produced plants characterized with longest shoots and more leaf chlorophyll content, bigger leaf area, greater fresh and dry weight of plant and at the same time produced higher early and total yield than those derived from cutting propagation. Economical comparison study was done to evaluate the cost price of seedlings and total yield obtained by cutting propagation and those obtained by conventional plants, the differences were calculated in terms of money according to the price of the market. Cutting techniques led to a reduction in the cost price of hybrid seedling production and increased the total income. It can be said that the asexual propagation by terminal cuttings is more economic and may be considered the best way to stop the increasing costs of hybrid seeds year after year and a best present procedure to replace the traditional nursery methods.

Propagation of Lagerstroemia Indica L.: Effect of IBA - Chemical formulations and cutting types on rooting behaviour of stem cuttings in relation to Biochemical changes

The study was conducted to ascertain the effect of IBA- chemical formulations and cutting types on rooting behaviour of Lagerstroemia indica during monsoon and spring seasons. The cuttings taken in monsoon (August) performed remarkably better than those taken in spring (March). Application of 0.4% IBA + 1% captan + 2% sucrose- talc registered the best sprouting (68.89%), rooting (75.56%) and root characteristics. The lateral cuttings resulted in significantly better rooting and root characteristics as compared to terminal and sub- terminal cuttings. Interaction effect revealed a maximum 86.67 per cent rooting when lateral cuttings were treated with the formulation of 0.4% IBA + 1% captan + 2% sucrose- talc and planted in monsoon. The study also revealed that cuttings with higher levels of total phenol, total carbohydrate and C/N ratio and low level of nitrogen exhibited better results.

Rooting Response of Azalea Cultivars to Hot Water Treatment Used for Pathogen Control

Submerging terminal leafy cuttings of Rhododendron L. ‘Gumpo White’ (‘Gumpo White’ azalea) in 50 °C water for 21 min was previously shown to eliminate binucleate Rhizoctonia species, the cause of azalea web blight, from plant tissues. Before considering commercial use of this practice, a better understanding of the rooting response and tissue sensitivity of evergreen azalea cultivars to 50 °C water was needed; therefore, the current study was conducted. Terminal cuttings of the azalea cultivars Conleb (Autumn Embers), Fashion, Formosa, Gumpo White, Hardy Gardenia, Hershey Red, Macrantha Pink, Midnight Flare, Red Ruffles, Renee Michelle, Roblel (Autumn Debutante), and Watchet were collected and submerged or not submerged in 50 °C water for 20 min before propagation in one experiment. All 12 cultivars tolerated 50 °C water for 20 min. Cuttings collected from the 12 cultivars were submerged in 50 °C water for 20, 40, 60, and 80 min in a second experiment. The cultivars varied in sensitivity when exposed to 50 °C water for 60 to 80 min resulting in differing responses in root development and final leaf count. In a third experiment, degrees of leaf damage caused by hot water submersion or by leaf removal were evaluated for the effect on root development and subsequent leaf count on rooted cuttings of ‘Gumpo White’ and ‘Roblel’. Induced incremental increases in leaf damage from hot water resulted in incremental reductions in the final leaf count and extent of root development for ‘Gumpo White’ and ‘Roblel’ while increasing percentage of leaf removal caused no reduction until 75% or greater leaf area was removed. Despite the risk imposed by submersing azalea cuttings in 50 °C water, all 12 azalea cultivars were tolerant of submersion durations long enough to eliminate binucleate Rhizoctonia species from stem and leaf tissue with only a low likelihood of sustaining detrimental damage.