Plug Trays Research Articles

Summary of the Developing Status of Greenhouse Tray Seeder and Seed Metering Device

The precision plug tray seeder is mainly used to implement precision seeding, and it is the key equipment to accomplish the goal of mechanized and automated seedling in the greenhouse. The plug seedlings planter can greatly improve the productivity of labor and reduce labor intensity at the same time. The seed metering device is the core component of precision plug tray planter. Its performance directly influences the production, the sowing quality and the cost. The purpose of this paper is to introduce the study of the plug seedlings planter for domestic and abroad, and particularly Introduce three typical seeder (plate-typeneedle-likeroller-type). Keywords:Seeder;Seed Metering Device;Plug Seedlings;Greenhouse.

THE QUALITY INDEX - A NEW TOOL FOR INTEGRATING QUANTITATIVE MEASUREMENTS TO ASSESS QUALITY OF YOUNG FLORICULTURE PLANTS

THE QUALITY INDEX - A NEW TOOL FOR INTEGRATING QUANTITATIVE MEASUREMENTS TO ASSESS QUALITY OF YOUNG FLORICULTURE PLANTS

Machine vision techniques for the evaluation of seedling quality based on leaf area

Highly efficient automated transplanters in greenhouses are of great convenience to growers. These tools perform various tasks, including the removal of bad plugs and the fixing of empty cells in plug trays. Leaf area of a seedling is an important indicator of its quality. Here, a vision system was used to measure the leaf area in each cell to distinguish “bad” and “good” plugs. Based on the principle of proportion in area, the procedures for processing top-view seedling images and a method for calculating each the leaf area of each seedling in the plug tray were investigated. Overlapping of the leaves across the surface of the cell resulted in failures in identification, which is a key point to be resolved. A decision method combining the region centre of cross-border leaves, and a methodology for the improved watershed segmentation for overlapping leaf (OL) images, were developed. Seedlings of tomato, cucumber, aubergine and pepper, at suitable transplanting stages, were used to test the efficacy of the quality evaluation program. Through the segmentation of 40 seedling images (10 for each vegetable seedling), the improved watershed segmentation lessened the initial partitions by 45–55% compared with the conventional watershed algorithm. The OLs were successfully segmented. The relative identification accuracy of seedling quality was 98.6%, 96.4%, 98.6% and 95.2% for tomato, cucumber, aubergine and pepper, respectively. The errors were mainly attributed to horticultural practices. The results showed that this system of identifying seedling quality was suitable for application in automated transplanters.

Production of rocket (Eruca sativa Mill.) on plug trays and on a floating system in relation to reduced nitrate content

The effect of the growth system on the yield and nitrate content of rocket (Eruca sativa Mill.) was evaluated in two experiments. In the first experiment, different sizes of cells in plug trays and different fertilization treatments were tested. In the second, a floating system was used with different substrates and the nitrate content in rocket leaves was analysed. The size of the cells did not affect the yield of rocket significantly but the yield was notably higher (2.02 - 2.21 kg m-2) when plugs were fertigated once per week with 6:12:36 + ME + natural biostimulant in comparison with plugs fertigated only with a water soluble fertilizer (1.53 - 1.74 kg m-2). The best yield was obtained in vermiculite and perlite in 20 ml cells (2.13 and 1.89 kg m-2). The different substrates used in the floating system had no effect on the dry matter content, which was on average 13.7 % and was significantly lower than the dry matter content of leaves grown in peat (19.1 %). The nitrate content in leaves measured a day before and 10 days after the replacement of the nutrient solution with tap water, fell greatly from 4,288-6,764 mg NO3 kg-1 FW to 52-634 mg NO3 kg-1 FW.

Environment Friendly Salt Coating For Root Pruning Of Sweet Pepper Seedlings

This study was done to minimize excessive growth and root mat formation which is a problem during preparation of seedlings in sweet pepper (Capsicum annuum L.) seedlings. The experiment was laid out in a completely randomized design (CRD) with 3 replications. Hybrid CV. ‘Sonik’ seeds were planted in plug trays coated with latex paint containing 0%, 1%, 3%, 5%, 7%, 10% and 15% NaCl (w/v) and compared with an uncoated control. Results showed that NaCl coating significantly minimized excessive growth rate and root mat formation. Seedlings from the treatment produced more fibrous roots. Even though before transplanting, untreated seedlings were taller with longer root length, significantly higher fresh and dry weight of shoots and roots; after transplanting, seedlings from NaCl coated trays showed better performance with taller plants, longer roots, and higher fresh and dry weights of shoots and roots. The 7% NaCl treatment gave superior performance among the treated and control plants. The Journal of Agriculture and Environment Vol:12, Jun.2011, Page 74-80 DOI: http://dx.doi.org/10.3126/aej.v12i0.7566

Efficacy of Cork Granulates as a Top Coat Substrate Component for Seed Germination as Compared to Vermiculite

A top coat is a lightweight substrate component used in seed germination. The seeds are typically placed on a substrate such as peat and then the seeds are covered with a layer of the top coating substrate. The top coat serves to maintain adequate moisture around the seeds and to exclude light. Vermiculite and cork granulates (1 mm) were used as top coat substrates for seed germination to determine if cork granulates could be successfully used as an alternative to vermiculite. The cork granulates had a bulk density of 0.16 g·cm−3, which was higher than that of vermiculite that had a bulk density of 0.12 g·cm−3. Cork granulates had an air-filled pore space of 22.7% (v/v), which was higher than vermiculite which was 13.2%. The water-holding capacity of vermiculite was 63.4% (v/v), which was higher than that of cork granulates that was 35.1%. Seeds of ‘Rutgers Select’ tomato (Solanum lycopersicum), ‘Dazzler Lilac Splash’ impatiens (Impatiens walleriana), ‘Orbital Cardinal Red’ geranium (Pelargonium ×hortorum), ‘Better Belle’ pepper (Capsicum annuum), and ‘Cooler Grape’ vinca (Catharanthus roseus) were placed on top of peat and covered with a 4-mm top coating of either vermiculite or cork granulates. For tomato, impatiens, and vinca, days to germination were similar between seeds germinated using vermiculite and granulated cork as a top coat. Days to germination of geranium and pepper were significantly different with geranium and pepper seeds coated with cork granulates germinating 0.7 and 1.5 days earlier than those coated with vermiculite. For tomato, impatiens, and geranium, the number of seeds germinating per plug tray was similar between the top coats. Number of seeds germinating per tray for pepper and vinca were significantly different. Pepper had an average of 2.8 more seeds germinating per tray, and vinca had an average of 2.4 more seeds germinating per tray if seeds were germinated using granulated cork vs. vermiculite. For all species, dry shoot and dry root weights were similar for seedlings germinated using cork and vermiculite top coats.

NFT 수경재배에서 양액 종류 및 삽수 크기가 고구마 바이러스 무병주 생육에 미치는 영향

To develop a technique for mass-propagation of virus-free sweet potato [Ipomoea batatas (L.) Lam.] plant using nutrient film technique (NFT), the growth characteristics of 4 cultivars as affected by nutrient solution composition and cutting size were investigated. 72 cells (35 mL/cell) plug trays filled with vermiculite and perlite (1:1, v/v) were used. Vine length, fresh and dry weights of virus-free plants were the greatest in the nutrient solution recommended by National Horticultural Research Station in Japan, followed by that recommended by National Institute of Horticultural & Herbal Science in Korea, and Yamazaki's nutrient solution for lettuce. The growth of uppershoot cuttings was the best among 4 subsections of cutting. Vine length, and fresh and dry weights increased in the longer cutting treatments, and were better in 'Shinzami' and 'Yeonhwangmi' than those in 'Mannami' and 'Shincheonmi'. Vine diameter and length of the longest root were not significantly affected by the cutting size and cutting source. The growth characteristics of the single node cutting were not significantly different from those in 2-node cutting. The efficiency of rapid mass-propagation could be promoted with single node cuttings and uppershoot cuttings grown in NFT system.

Determining the Flowering Requirements of Two Aquilegia Cultivars

Flowering of the herbaceous perennial Aquilegia is generally considered to require vernalization after seedlings are mature, whereas photoperiod has little or no effect. We performed experiments to determine the flowering responses for two Aquilegia ×hybrida varieties, one of which reportedly has reduced cold requirements. Seedlings of Aquilegia ‘Origami Blue and White’ and ‘Winky Double Red and White’ with three to five leaves were either placed directly into a 5 °C cooler with low-intensity lighting for 9 hours/day or transplanted to 13-cm containers and grown (bulked) for 0, 3, or 6 weeks at 20 °C under 9-hour short days (SDs) or 16-h long days (LDs). Plants were then cooled at 5 °C for 0, 5, or 10 weeks and placed in a common forcing environment at 20 °C under LDs. Flowering response of the two cultivars differed markedly. All Aquilegia ‘Origami Blue and White’ plants placed directly into the forcing environment flowered and in a mean of 93 days. Flowering percentage of plants cooled in the plug tray decreased with increasing duration of cold treatment, and only 15% flowered after a 10-week cold treatment. All plants bulked for 3 or 6 weeks before cold treatment flowered after 25 to 36 days in the forcing environment. Adding bulking and forcing time together, time to flowering of ‘Origami Blue and White’ was complete and most rapid (62 days) when plants were bulked for 3 weeks under SDs and then forced under LDs. In contrast, no ‘Winky Double Red and White’ plants flowered without cold treatment, and 6 weeks of bulking followed by 10 weeks of cold was required for 100% flowering. These results indicate that ‘Origami Blue and White’ has a relatively short juvenile phase and flowering was promoted by SD bulking or cold treatment, whereas ‘Winky Double Red and White’ has a longer juvenile phase and requires cold for flowering.

생물반응기를 통해 대량증식된 사계성 딸기 '고하' 소식물체의 순화용기에 따른 생육특성과 묘생산 경제성

본 실험은 생물반응기를 통해 대량증식된 사계성 딸기 조직배양묘의 적정 순화용기를 선발하기 위해 실시하였다. 순화용기는 플라스틱투명용기, 플러그 트레이, I-포트 및 흑색비닐포트 등 4가지를 사용하였다. 토양함수율 10%이상 지속일수는 플라스틱 투명용기가 5일, 흑색비닐포트가 3-4일, 플러그 트레이 2일, I-포트가 1일 순이었다. 생존율은 흑색비닐포트가 80%, 플라스틱투명용기가 70%, I-포트가 55% 및 플러그 트레이가 15% 순으로 나타났다. 또한 생육량은 플라스틱 투명용기가 가장 왕성하였고, 흑색비닐포트와 플러그 트레이는 비슷하였으며, I-포트가 가장 저조하였다. 런너 발생은 흑색비닐포트가 주당 3.3개로 가장 많았으며, 플라스틱투명용기가 2.9개, 플러그 트레이가 1.6개 및 I-포트가 1.2개 순으로 나타났다. 총 생산비용은 흑색비닐포트가 44,405,300원/10a로 I-포트의 51,064,700원/10a보다 6,659,400원/10a이 더 절감되었으며, 총 생산주수도 흑색비닐포트가 102,718주/10a로 I-포트의 72,452.9주/10a보다 30,265.1주/10a 더 생산되었다. 또한 주당 생산비용은 흑색비닐포트가 432.3원으로 I-포트의 704.8원에 비해 272.5원의 감소하였다. 따라서 생물반응기를 통해 대량증식된 사계성 딸기 조직배양묘의 순화용기는 흑색비닐포트가 적당하였다. This study was conducted to find out the optimum container for increasing acclimatization rate of in vitro mass propagated plantlets of Ever-bearing strawberry (Fragaria <TEX>${\times}$</TEX> ananassa Duch.) via bioreactor. Four types of containers were used such as transparent plastic container (TPC), plug tray (PT), I-pot (IP), and black vinyl pot (BVP). Number of date maintaining soil water content above 10% was five days in TPC, three to four days in BVP, two days in PT, and one day in IP. Survival rate of plantlets was 80% in BVP, 70% in TPC, 55% in IP, and 15% in PT. In TPC, growth increment of plantlets was the greatest among all the tested containers and the lowest in IP. Numbers of runner per plant were 3.3 in BVP, 2.9 in TPC, 1.6 in PT, and 1.2 in IP. Total cost was 44,405,300 won/10 a in BVP, resulting in reducing more 6,659,400 won/10 a than IP's (51,064,700 won/10 a). Around 102,718 plants/10 a were produced by using BVP, suggesting that 30,265.1 plants/10 a more could be produced than IP (72,452.9 plants/10 a). Production cost per plant was 432.3 won in BVP, resulting in reducing 272.5 won than IP's (704.8 won). As a result, BVP was appropriate for acclimatization of in vitro plantlets through bioreactor system.

점토광물 처리에 따른 상토에서 고추의 초기생장 효과

최근 원예산업의 발달로 인해 모종의 연중 생산량이 증가되고 플러그 트레이를 이용한 양질의 모종을 편리하게 키울수 있는 육묘기술이 보급되면서 상토의 사용량이 크게 증가되었다. 본 연구에서는 4가지 점토광물 일라이트, 필라이트, 제올라이트, 벤토나이트의 상토 첨가 시 고추의 초기 성장에 대한 효과를 알아보았다. 또한 일라이트 처리 시 고추 잎과 줄기의 시료에 대한 프로테옴 분석을 수행하였다. 포트에 있는 상토에 4가지 점토광물을 각각 처리한 이후에 트레이서 재배된 모종 중에서 건강하고 규칙적인 크기를 가진 모종을 선별하여 포트에서 재배하였다. 본 연구는 6주 동안 충북대학교 유리 온실에서 수행되었다. 4가지 점토광물 처리에 따른 고추의 초장, 뿌리와 줄기의 생중량과 건중량은 무처리와 비교해서 모든 점토광물 처리구에서 높게 나타났다. 그리고 고추의 뿌리, 줄기, 잎에서 양이온 <TEX>$K^+$</TEX>, <TEX>$Ca^{2+}$</TEX>, <TEX>$Mg^{2+}$</TEX>의 흡수량은 무처리구보다 모든 점토광물 처리구에서 높게 나타났다. 고추 시료에 대한 프로테옴 분석을 실시한 결과 잎 조직에서는 에너지 대사에 관련 단백질인 plastid fructose-1, 6-bisphosphat aldolase class 1, aldolase 및 glyceraldehydes 3-phosphate dehydrogenase가 대조구보다 더 많이 발현되는 것을 보여주었다. 줄기 조직에서는 에너지 대사에 관련된 NAD-dependent formate dehydrogenase, potassium(K) 운송 단백질, 지베렐린 반응 조절에 관련된 GIA/RGA 단백질 등이 대조구보다 더 많이 발현되는 것을 보여주었다. 프로테옴 분석으로 얻어진 결과를 보면 일라이트 처리 시 특이하게 차별적으로 발현된 단백질이 고추의 초기 생장 증진에 관련된 것으로 사료된다. 그러므로 점토광물의 처리에 대한 채소작물의 반응에 관련된 몇몇 단백질의 동정은 그들의 분자적인 기작 구명을 이해하는 데 새로이 기여할 것으로 사료된다. As the advanced seeding technology through use of plug tray for good cultivation of seeds was propagated along with the expansion and development of horticultural industry, the use of bed soils as growing medium has recently been increased. In this study, the effects of the four clay minerals such as illite, phyllite, zeolite, and bentonite on the early growth of red pepper in the bed soil were investigated. Furthermore, proteome analysis for the leaf and stem samples of red pepper treated with only illite was performed. Of the seedling cultured, the healthy and regular size seeds were selected and cultivated in the pots, after they were treated with four clay minerals. The experiment was performed during the whole six weeks in the glasshouse of the Chungbuk National University. The growth lengths, fresh and dry weights of red pepper were significantly higher in the treatments of illite, phyllite, zeolite, and bentonite than in the control. In addition, the uptake of <TEX>$K^+$</TEX>, <TEX>$Ca^{2+}$</TEX>, and <TEX>$Mg^{2+}$</TEX> were higher in the treatment of illite, phyllite, zeolite, and bentonite than in the control. The 2-DE patterns for the red pepper by the applications of illite, phyllite, zeolite, and bentonite were similar to each other. Therefore, compared to the samples of control, the proteome analysis for the samples of red pepper treated by only illite were performed. Proteome analysis for red pepper showed that plastid fructose-1, 6-bisphosphate aldolase class 1, aldolase, and glyceraldehydes 3-phosphate dehydrogenase, all of which were involved in the energy metabolism, were highly expressed in leaf tissue by illite treatment. In stem tissue, NAD-dependent formate dehydrogenase involved in energy metabolism, potassium transport protein, and GIA/RGA-like gibberellins response modulator were highly expressed. Based on the results obtained from the proteome analysis, it appears that the proteins specifically and differentially expressed on the illite treatment may be involved in the enhanced growth of red pepper. The identification of some proteins involved in the response of vegetable crops to the treatment of clay mineral can provide new insights that can lead to a better elucidation and understanding of mechanism on their molecular basis.

GREENHOUSE BABY LEAF PRODUCTION OF LETTUCE AND KOMATSUNA IN SEMI-ARID CLIMATE: SEASONAL EFFECTS ON YIELD AND QUALITY

Greenhouse production of baby salad leaves is a means to provide a clean, safe product for consumers. However, productivity and nutritional quality is not well known especially under semi-arid greenhouse conditions. Three leafy greens, Lactuca sativa 'Red Salad Bowl', L. sativa 'Cimmaron Romaine' and Brassica rapa var. komatsuna were grown during two years (2008-2009) in a pad-and-fan cooled acrylic greenhouse in Southern Arizona using ebb-and-flood irrigation with perlite-based substrate contained in 72-cell plug trays. Nutrient solution was half-strength general purpose hydroponic formulation. Seeds were germinated in a temperature-controlled room for four days then moved to greenhouse for three weeks after which it was harvested. Leaves were harvested and the fresh weight recorded on a weekly basis. Carotenoids, ascorbic acid, phenolics and anthocyanins were the phytonutrients measured. Yield and quality were significantly affected by seasonal environment. Fresh weight ranged from 0.08 to 2.18 kg·m-2 for lettuce and 0.36 to 1.82 kg·m-2 for komatsuna per 3-week production cycle and was greatest during spring/summer season. Anthocyanin, strongly affected by season, ranged from 4.5 to 121.9 mg·kg-1 FW for lettuces. Total phenolics showed seasonal variation, concentration ranging from 526.9 to 1914 and 568.4 to 1602 mg·kg-1 FW for lettuces and komatsuna respectively. Anthocyanin and phenolics concentrations were greatest during winter season on fresh weight basis. Other phytonutrient concentrations were not clearly affected by season. Total carotenoids and ascorbic acid of lettuce grown in our greenhouse were comparable to, but anthocyanins were lower than, levels reported in the USDA database. Yield and quality of leafy greens is satisfactory but could be improved by further optimizing the greenhouse environmental conditions.

Development and Evaluation of a Two-Row Revolving Magazine Type Vegetable Transplanter

A 2-row vegetable transplanter with revolving magazine type metering mechanism was developed and field evaluated for Brinjal (Solanum melongena L.) crop. The seedlings of brinjal crop were grown in 98 cell (single cell volume of 22 cm3) plug trays in soil less media. Plant missing varied from 2.22 to 4.44 per cent. Upright plants (plants having 00 to 300 planting angle), depth of planting, plant mortality after 20 days were in the range of 8590 %, 5 to 6 cm and 3.33 to 4 %, respectively. The average field capacity of the machine was 0.122 ha.h-1 for brinjal crop.

Design on Plug Seedling Automatic Transplanter in Greenhouse

Transplanting of plug seedling is one of the most important operations during vegetable and flower production. Due to the higher labor intensity and lower efficiency for the operation, it is difficult to enlarge production scale for vegetables and flowers. Although transplanting of plug seedling is now common method, all operations are still manually conducted in China. To enlarge productivity for increasing food supply, it has become an urgent task to achieve automation of plug seedling transplanting for Chinese horticulture industry. This paper deals with the automatic transplanter for plug seedling, which is significant to promote development of production automation of seedling nursing and transplanting in China. Then, the simple, practical automatic transplanter for plug seedling, including manipulator, conveyor system for plug tray and flowerpots, overall structure and PLC control system was designed. Finally, Prototype was manufactured and performance tests were conducted. Results showed that the automatic transplanter had reliable transplanting performance.

Design and Experiment of the Pneumatic Plate-Type Vegetable Seeder

Structure plan of a new type of pneumatic plate-type vegetable seeder was put forward, and virtual prototype of the seeder was established in the paper. By kinematics simulation and analysis, L-shape arm length and minimum distance between metering device and cell plug tray were optimized. The machine control system and air pressure switch system were designed in detail. Results of orthogonal test show that, the main influence factor for single-seed rate and empty-seed rate is sowing efficiency, the second is diameter of suction hole, next is relative pressure, the minimum is interaction between those factors. The main influence factor for multi-seed rate is diameter of suction hole, the second is relative pressure, next is interaction between factors, the minimum is sowing efficiency. The best seeding effects can be achieved under the condition of 0.9 mm suction hole diameter, -4.5 kPa relative pressure, and 200-tray per hour sowing efficiency. The single-seed rate can be up to 93.59%, the empty-seed rate is 1.25%，and the multi-seed rate is 5.16%。

Effect of soaking of seeds in potassium silicate and uniconazole on germination and seedling growth of tomato cultivars, Seogeon and Seokwang

Experiments were conducted to investigate the effects of soaking seeds in potassium silicate and uniconazole on seed germination and seedling growth of two tomato cultivars. Tomato ( Lycopersicum esculentum Mill. ‘Seogeon and Seokwang’) seeds were put in a Petri dish filled with 15 ml of a solutions containing either 50 or 100 mg L -1 potassium silicate or uniconazole and were placed in an environment controlled chamber (25°C, 80% RH, dark) for 12 or 24 h. After the soaking treatment, seeds were washed in distilled water and were dried in a growth chamber (25°C, 80% RH, and in the dark) for 4 h. Seeds were sown in 288-cell (11 cc) plug trays containing a Tosilee medium and trays were layed out in a randomized complete block design on beds in a glasshouse. A nutrient solution was supplied uniformly for all treatments once a day through a sub-irrigation system. Soaking seeds in potassium silicate or uniconazole solution reduced germination percentage in both cultivars when compared to the control. In both cultivars, soaking treatment of uniconazole significantly reduced length of stem, hypocotyls, internode, leaf area and dry weight of stem and root, as compared to the control and other treatments. Root length increased significantly in all treatments when compared with the control. Hypocotyl length and plant height of 'Seogeon' seedlings were suppressed in the 100 mg L -1 potassium silicate treatment as compared to the control and water soaking. In contrast, height of ‘Seokwang’ seedlings increased by potassium silicate treatment. The chlorophyll fluorescence ratio (Fv/Fm) increased by low concentration of uniconazole treatment as compared to the control and other treatments. The growth of tomato seedlings was efficiently regulated by uniconazole 50 mg L -1 (12 h soaking) treatment. Key words: Chlorophyll fluorescence, plant growth retardants, plug plants, potassium silicate, seed treatment, silicon, uniconazole.

In vitro high-frequency regeneration of half-highbush ‘Northland’ blueberry

An efficient protocol is developed for adventitious shoot regeneration from nodal and leaf explants of the half-highbush blueberry cultivar ‘Northland’. In vitro-derived nodal segments are used to form adventitious shoots on pH 5.0 modified woody plant medium (WPM) containing 4 mg/L zeatin, 0.8% (w/v) agar and 2% (w/v) sucrose. This media is deemed suitable based on adventitious shoot multiplication rate and plantlet number and height, and it also achieves the best adventitious shoot induction from leaf explants. Shoots are rooted on half-strength modified WPM containing indole-3-butyric acid (IBA) or a-naphthaleneacetic acid (NAA) and 0 or 0.2% (w/v) activated charcoal, with 2 mg/L IBA and 0.2% (w/v) activated charcoal found best for easy root induction. Rooted plantlets are transferred to plug trays containing 1:1:1 peat:sand:vermiculite adjusted to pH 4.5 with ferrous sulphate, and readily acclimatized under greenhouse conditions.

LINER DIPS FOR GROWTH REGULATION OF VIGOROUS HERBACEOUS PERENNIALS

Many vigorous herbaceous perennials need early growth regulation. Treatment at the plug stage could improve early growth control or maintain product size in the plug tray. Concise (uniconazole, Fine Americas, Inc.), is a growth regulator labeled for use on ornamental greenhouse crops in the US. We treated plugs of five herbaceous perennials with a 2-minute dip into 0, 1, 2, 3, 4 or 5 mg/L Concise the day before planting into 1.1-liter pots filled with a peat-lite medium (ornamental grasses were maintained in the plug pots). Plant height was determined at 2 week intervals after treatment (WAT). Concise reduced shoot growth in a linear or quadratic correlation for all crops except Gaillardia × grandiflora ‘Goblin’ which was not affected by the treatments. The ornamental grasses differed in responsiveness with Miscanthus sinensis ‘Gracillimus’ showing little response until 8 WAT while Calamagrostis × acutifolia ‘Karl Foerster’ exhibited a 22% reduction in plant height at 2 WAT with a 1 mg/L Concise dip followed by a 31% height reduction and 26% reduction in shoot dry weight at 12 WAT. A 1 mg/L liner dip of Concise gave significant height reduction of Phlox paniculata ‘David’ and Rudbeckia fulgida var. sullivantii ‘Goldsturm’ through 8 and 10 WAT, respectively. Liner dips are an effective means of growth regulation that can reduce worker contact with the chemical solutions and provide baseline control of vigorous or hard-to-control herbaceous perennial crops.

콩.옥수수 육묘용 파종기 개발에 관한 연구

Soybean (Glycine max Merr.) and corn (Zea mays L.) transplanting has increased because soybean and corn crops cultivated by the direct seeding method were often damaged by wild birds. The purpose of this study is to develop a seeder to sow soybean (Glycine max Merr.) and corn (Zea mays L.) in a plug tray. In order to find out design factors for a metering device of the seeder, metering characteristics on metering hole size and roller speed were experimentally investigated. Soybean (cv. `Daewon`) and corn (cv. `Mibaekchal`) were used as a materials for testing the seeder in this experiment. The metering hole size of roller suitable for Daewonkong and Mibaekchal was determined. Daewonkong was suitable for hole diameter of 10 mm and hole depth of 5.5 mm, and Mibaekcal was suitable for hole diameter of 9 mm and hole depth of 5.5 mm. At a brush length of 4 mm, one grain seeding rates of Daewonkong and Mibaekchal was 99% and 93% respectively. By inducing Mibaekchal to the hole by swing, one grain seeding rate of that increased from 91.9% to 97.7%. When roller speed is 4 m per minut, seeding efficiency of prototype was 110 sheets per hour.

Timing and Duration of Supplemental Lighting during the Seedling Stage Influence Quality and Flowering in Petunia and Pansy

Increasing the photosynthetic daily light integral (DLI) during the seedling stage promotes seedling growth and flowering in many bedding plants. Our objective was to determine the impact of increased DLI for different periods during the seedling stage on young plant quality and subsequent growth and development. Seeds of petunia (Petunia ×hybrida Vilm.-Andr. ‘Madness Red’) and pansy (Viola ×wittrockiana Gams. ‘Delta Premium Yellow’) were sown into 288-cell plug trays and placed under a 16-h photoperiod provided by sunlight plus 90 μmol·m−2·s−1 [supplemental lighting (SL)] or 3 μmol·m−2·s−1 [photoperiodic lighting (PL)] from high-pressure sodium lamps when the ambient greenhouse photosynthetic photon flux was less than 400 μmol·m−2·s−1 from 0600 to 2200 hr. Plants were grown at 20 °C under PL or SL for the entire seedling stage or were exposed to SL for one-third or two-thirds of the seedling stage. Seedlings were then transplanted into 10-cm pots and grown until flowering with SL at 20 °C. Shoot dry mass of transplants increased linearly with increasing DLI provided to seedlings in petunia (y = −4.75 + 1.86x, R2 = 0.76) and pansy (y = −3.94 + 3.47x, R2 = 0.78) in which y = dry mass (g) and x = DLI (mol·m−2·d−1). SL during the last two-thirds or the entire plug stage increased shoot dry mass and the number of leaves in both species compared with SL during the earlier stage or PL. SL during the last two-thirds or the entire plug stage accelerated flowering, but plants had a lower shoot dry mass and flower bud number at first flowering compared with that in SL during the first third or two-thirds or that in PL. Therefore, SL generally had greater effects on transplant quality and subsequent flowering when provided later in the plug stage than if provided earlier in production.

PLUG-TRAY NURSERY RAISING TECHNOLOGY FOR OFF-SEASON CUCURBITS CULTIVATION

In India, cucurbits are mainly sown by seeds during their normal season of cultivation. Seedlings of these vegetables can not be raised through traditional system of nursery raising on soil beds, because these vegetables are not tolerate against slightest damage to their root and shoot system during their uprooting and transplanting. This kind of damage can not be avoided in the traditional system of seedling raising, therefore it was not in general practice to transplant these vegetable through seedlings. Thereafter, a method of nursery raising was evolved in which off-season seedlings were raised in small polyethylene bags using soil and compost (50:50) as a media, but this system needs lot of protected space and is labour intensive. During the transportation process the crop in main field needs large quantity of media and does high damage to root system ant it is also not very eco-friendly, therefore, not accepted by growers in India But at the Centre for Protected Cultivation Technology of the Indian Agricultural Research Institute, New Delhi a nursery raising technology for cucurbits had been developed and standardized in which seedlings of major cucurbits are raised in multi-celled plastic plug trays containing each cell of a volume of 18-20 cc and inverted pyramid in shape by using coco-peat, vermiculite and perlite as soil-less media in 3:1:1 ratio on volume basis. This technique is not only efficient in vigorous root development but also suitable to avoid any damage to the roots and shoots of the seedlings at the time of transplanting. This technology is economical and suitable for the cucurbits growers in northern plains of India, because with the introduction of this technique, farmers can grow large number of seedlings as per requirement for off-season cultivation of cucurbits (with various varieties) for fetching high price of their off-season produce. The plug tray nursery raising technology is suitable for Melons, gourds and squashes for their off season cultivation in Northern India. This kind of technology is good option for the agri. entrepreneur by the progressive farmers or unemployed educated youths in major vegetable growing parts of the country.