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Division of Plant and Soil Sciences, West Virginia University, P.O. Box 6108, Morgantown, WV26506-6057, USA.

DOI: https://doi.org/10.37855/jah.2010.v12i02.19

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Abstract: Four microclimate modification methods including spun-bonded and slitted low tunnels both with and without the addition of water-filled plastic tubes were tested for their effect on early and total yields of warm and cool season vegetable crops in Morgantown, West Virginia, USA. Peppers, tomatoes, radishes, and lettuce were organically grown in 2006 and 2007. Early season pepper yields were higher when water tubes were included with low tunnels while early tomato yields did not differ. Total yields for warm season crops in some microclimate modification treatments were higher than the control, and harvests started up to four weeks earlier in the spring. Cool season crop yields in the four treatments showed no increase over the control despite one to three weeks earlier harvests for radish and lettuce. These results show potential for earlier safe planting dates and increased yield, especially in warm season vegetable crops using low tunnels and water tubes. Additionally, economic analysis demonstrated a potential for increased profits over control plots using these microclimate modification techniques.

Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan; Faculty of Life and Environmental Science, Shimane University, Nishikawatsu-cho, Matsue, Shimane, 690-8504, Japan; Department of

DOI: https://doi.org/10.37855/jah.2010.v12i02.20

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Abstract: The grape berry morphologically consists of epidermis, an outer wall, an inner wall and placenta. The inner contents such as soluble solids, organic acids and moisture distribution of grape berries are dramatically changed during the veraison between the growth and ripening period. However, we know little about the changes in the inner contents of the outer wall, inner wall and placenta. Our purpose of the study is to clarify the tissue specificity of the total soluble solids content, sugar composition, flesh firmness and moisture distribution of 'Kyoho' grape berry during growth and ripening period. The moisture distribution of the grape berries was analyzed with magnetic resonance imaging (MRI). The total soluble solids contents of the outer wall were higher than those of the inner wall during the investigation period. In this study, fructose, glucose and sucrose were detected in the berries. The concentrations of these sugars in the outer wall were higher than those in the inner wall; however, the components of these sugars were not different between the outer wall and inner wall. Even within the same berry, the flesh firmness and the moisture distribution were different from one part of the tissue to another. These results indicate that the growth rate of grape berry varies considerably among the different parts of the berry.

Faculty of Applied Science, Universiti Teknologi MARA, Malaysia (UiTM), Shah Alam 40450, Selangor, Malaysia.

DOI: https://doi.org/10.37855/jah.2010.v12i02.21

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Abstract: Application of edible coating represents a method that can extend the shelf life of picked guava by minimizing the loss of weight mainly due to natural migration process of moisture and gases. Response surface methodology (RSM) was employed to search for best composition of edible coating which comprised of three variables namely palm stearin, palm olein and beeswax. Based on central composite rotatable designs of RSM and weight loss as response, 15 coating compositions were established involving 8 factorial points, 6 axial points and 1 centre point. From the RSM-generated model, optimum coating composition for minimizing guava weight loss was identified as palm stearin 4.5% (w/v), palm olein 1% (v/v) and beeswax 1% (w/v). Under this optimum composition, the predicted weight loss of coated guava was 7.18%, whereas, the experimental weight loss of coated guava was 7.51% after tenth days of storage period. The RSM-predicted and experimental weight loss were not significantly different from each other. The weight loss of uncoated guava was 3 times higher (25%) after 8 days of storage as compared to coated guava. Thus, the use of optimum composition of edible coating provides acceptable alternative for post harvest control of weight loss of guava during storage.

Faculty of Agriculture, Gomal University, Dera Ismail Khan, Pakistan; School of Plant Sciences, The University of Reading, Reading, UK; University College of Agriculture, Bahauddin Zakariya University, Multan, Pakistan.

DOI: https://doi.org/10.37855/jah.2010.v12i01.02

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Abstract: An experiment was carried out to study flowering response of six facultative short day plants (zinnia cv. Lilliput, sunflower cv. Elf, French marigold cv. Orange Gate, African marigold cv. Crush, cockscomb cv. Bombay and cosmos cv. Sonata Pink) under four distinct controlled photoperiods (8, 11, 14 and 17 h d^-1). A curvilinear facultative response was observed in almost all cultivars studied. zinnia, sunflower, French marigold, African marigold, cockscomb and cosmos took minimum time to flower when grown under 8 h d^-1 photoperiods however it was significantly (P<0.05) increased when photoperiod was increased to 17 h d^-1. These findings revealed plant scheduling prospect that is, the flowering time of facultative SDPs grown under long day photoperiod can be extended in order to continue supply of these plants in the market

Korea National College of Agriculture and Fisheries, 11 Dongwhari Bongdam Hwasunsi Kyonggido, R.O. Korea 445-890, Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695-7609, Department of Biology, Elon University, Elon, N

DOI: https://doi.org/10.37855/jah.2010.v12i01.03

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Abstract: Ground, composted rice hulls were combined as a root substrate component with peat moss and coir at five rice hulls percentages (0, 25, 50, 75, and 100) in a factorial design. Seventy-five percent of the rice hull particles were 0.51 to 1.40 mm and 90% of the particles were 0.51 to 2.00 mm. In physical property evaluations, increasing the percentage of rice hulls in both the peat moss and coir series of substrates increased the dry bulk density and airspace at container capacity; however, as air space increased, container capacity and available water decreased. In the first two of three plant growth experiments, Impatiens walleriana Hook. f. 'Super Elfin White' was grown in 288 cell plug trays. In the third experiment, Verbena Xhybrida Voss. 'Romance Deep Rose' was grown in 48 cell bedding plant flats. Due to problems with high pH in the coir, only the peat moss growth results were reported. Overall, growth was best in 25% rice hulls plus 75% peat moss. Rice hulls increased substrate Ca²+ and Mg²+ in both the peat moss and coir. Adding rice hulls to the substrate increased K+ in peat and decreased K+ in coir. There was no effect of rice hulls on substrate NO₃^- -N, NH₄+-N, and PO₄-P in the substrate solution. Ground, composted rice hulls are a potential alternative component of soilless substrate for plugs and bedding plants.

CONICET, Cdtedra de Genetica, Facultad de Ciencias Agrarias UNR, CC 14 S2125ZAA, Zavalla, Argentina. FONCyT, Cdtedra de Genetica, Facultad de Ciencias Agrarias UNR, CC 14 S2125ZAA, Zavalla, Argentina. CIUNR, Cdtedra de Genetica, Facultad de Ciencias Agr

DOI: https://doi.org/10.37855/jah.2010.v12i01.04

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Abstract: Five recombinant inbred lines, generated from a single interspecific cross S. lycopersicum x S. pimpinellifolium, were crossed in a complete diallel combination without reciprocal. Fruit quality traits were analyzed according to Griffing (1956), method 2, model 1 (fixed effects). Significant general and specific combining ability (GCA and SCA) effects were found for all traits. Weight, reflectance percentage, chroma index, firmness, soluble solids content, pH and titratable acidity presented SCA values greater than GCA values, indicating nonadditive effects. Both additive and nonadditive effects were significant in determining diameter and shape. Positive unidirectional dominance was found for shape, shelf life and chroma index, while negative unidirectional dominance was involved in the expression of weight, diameter, height, reflectance percentage and firmness. Bidirectional dominance was found for soluble solids content, pH and titratable acidity. In spite of being a genetic pool generated from a single interspecific cross, high levels of genotypic and phenotypic variability was found among the fifteen genotypes for important agronomic traits. Both additive and nonadditive effects were important in the genetic determination of these traits.

Institut des Regions Arides, 4119 Medenine, Tunisie. Institut Superieur des Sciences et Technologie de I'Environnement BP 1003, Hammam-Lif2050, Tunisie.

DOI: https://doi.org/10.37855/jah.2010.v12i01.05

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Abstract: Field experiments were performed to study the impact of two different irrigation systems (surface drip and surface) on water use efficiency and yield components of a pepper crop (Capsicum annum. L). Irrigation scheduling was carried out based on estimated crop evapotranspiration (ETc) using crop coefficients for pepper and reference evapotranspiration ETo calculated using the Penman-Monteith equation (Allen et al., 1998). The crop received total water needs computed according to Veirmeiren and Jobling (1983) procedure for surface drip irrigation. Border irrigation was scheduled by Cropwat model (Smith, 1992). Experimental plots were irrigated simultaneously during the appropriate duration for each one and received the same nutrients (N, P, and K) ratio. Comparison was made on fruit number per plant, fruit weight, fruit weight by harvest and yield per unit surface. The results showed that compared with surface irrigation, drip irrigation presented a significant difference in total fruit yield and water use during cropping season (May to September). With drip irrigation, average yield was 19.73 kg m² which was 68% greater than that irrigated with surface irrigation (11.90 kg m²). Applied water volume by unit production (m³/kg) was 0.38 for drip and 1.05 for border, respectively. Drip irrigation increased fresh pepper fruit yield with a reduction of 60% in water use compared to traditional surface irrigation.

Laboratorios de Bioquimica and Viticultura - Enologia, Facultad de Agronomia, Avda. Garzon 780 CP 12900. Montevideo, Uruguay, Instituto Nacional de Vitivinicultura, Dr. Pouey 463. Las Piedras, Uruguay.

DOI: https://doi.org/10.37855/jah.2010.v12i01.01

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Abstract: Anthocyanins accumulation and gene expression in berries of Vitis vinifera L. cv. Tannat trained in Lyre system was investigated. Expression of genes involved in anthocyanins biosynthetic pathway as chalcone synthase (CHS), flavonoid 3-hydroxylase (F3H), dihydroflavonol 4- reductase (DFR), and UDP-glucose flavonoid-3-O- glucosyl transferase (UFGT) was examined. On the other hand, the influence of plant architecture, Lyre and vertical shoot positioned (VSP) trellis systems, on anthocyanins accumulation and gene expression was also analyzed. Final contents of total anthocyanins were not affected by trellis systems but varied in two years with different water deficit imposition period. However, the individual profile of the genes and anthocyanidins modified according to the moment of water deficit imposition (veraison or harvest) and by the trellis systems (Lyre or VSP). Analysis of gene expression in Lyre along the berry development period showed that low leaf water potentials after veraison cause an earlier and greater induction compared with expression in a year with low leaf water potential at harvest. At harvest, the hydric deficit induced an increase in the expression of CHS, F3H and DFR genes and a higher total anthocyanins content. The study revealed that plant architecture affect the expression of anthocyanins related gene in berries possibly by modifying the canopy microclimate.

School of Biological & Conservation Sciences, University of KwaZulu-Natal, Westville Campus, Private bag X54001, Durban 4000, South Africa. Department of Horticulture, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt.

DOI: https://doi.org/10.37855/jah.2010.v12i01.06

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Abstract: Hormonal control of flower induction in vitro was investigated in Gentian. The effect of PBZ concentrations on flowering was studied in plantlets cultured in MS medium containing 30 g L^-1sucrose. Paclobutrazol (PBZ) concentration at 1.0 mg L^-1 induced the highest flowering in terms of flowering percentage (91.5%), number of flowers, days to first flowering, flower length and flower diameter. PBZ did not trigger flowering but it rather stimulated flowering and its role seemed to be additive but not essential for flowering. Comparison between solid and bioreactor cultures (continuous immersion with a net) revealed that shoot multiplication and growth were more efficient using bioreactor culture. The highest shoot number per explant (29.9) was obtained in bioreactor culture. Regenerated shoots were cultured microponically for 6 weeks. Hundred percent of plants rooted and were acclimatized successfully in growing media containing perlite: vermiculite (1:1).

Jomo Kenyatta University of Agriculture and Technology, Botany Department, P.O. Box 62000 Nairobi, Kenya. Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00100 Rome, Italy. Economic Botany, Missouri Botanical Gar

DOI: https://doi.org/10.37855/jah.2010.v12i01.07

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Abstract: Citrullus lanatus (Thunb.) Mansf. (Watermelon) is an important crop plant in Kenya. Being monoecious, watermelon is entirely dependent upon pollination services usually by insects for production. Although the centre of origin for this plant is thought to be tropical Africa, essentially not much has been studied of its pollination requirements in this region. The current study investigated the identity of the wild pollinators of watermelon, their behaviour and relative pollination efficiencies at Yatta, a farm near Thika (Eastern Province). The main pollinator for this crop was found to be the honey bee, Apis mellifera but three wild species of Lasioglossum were found as important pollinators. These wild bees have a significantly higher (P< 0.0001) pollen deposition on stigmas of watermelon than honeybees. One of the Lasioglossum (Ctenonomia) sp. 4 deposited on average three times as much pollen as the honeybee. At about the time of stigmatic receptivity, the number of visits by this species to female flowers increases until it equals visits to male flowers irrespective of number of flowers per plot. This behavioural pattern coupled with the high pollen deposition potential makes Lasioglossum (Ctenonomia) sp. 4 a superior candidate as an alternatively managed pollinator for watermelon. Knowing that visitation occurs mostly in the morning, and that flowers last only for one day, spraying can be done in the later hours of the day when the pollinators have virtually stopped foraging on the flowers. In view of the reported pollinator decline globally, the wild pollinator species reported in this study warrant further investigation on their nesting biology and potential for domestication.

G.B. Pant Institute of Himalayan Environment and Development, Sikkim Unit, Pangthang, Post Box 24, Gangtok, East Sikkim-737101, India.

DOI: https://doi.org/10.37855/jah.2010.v12i01.08

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Abstract: The first successful micropropagation protocol was developed for an important Sikkim Himalayan Rhododendron, R. dalhousiae Hook. f. also known as Lahare Chimal in Sikkim. In vitro raised shoot tip explants from R. dalhousiae were used to produce multiple shoots on a medium containing various concentrations of growth regulators. Among the combinations used, Murashige and Skoog (MS) medium containing 5 mg L^-1 2-isopentenyladenine (2iP) along with additives such as, 100 mg L^-1 polyvinyl pyrrolidone (PVP), 100 mg L^-1 ascorbic acid, 10 mg L^-1 citric acid was found to be best for induction of multiple shoots within 12 weeks of culture. The combination of 5 mg L^-1 2iP +1 mg L^-1 indole-3-acetic acid (IAA) resulted in further multiple shoot production than using them alone. Rooting of shoots in vitro was achieved on MS medium containing 0.2 mg L^-1 indolebutyric acid (IBA). Rooted plantlets were transferred to small polythene bags containing autoclaved fresh peat moss and soil (1:3) and maintained with a high humidity for acclimation. These in vitro-raised plants grew normally in greenhouse and natural habitat (arboretum of the Institute) without showing any morphological variation. The protocol developed from the present study could be used for large scale multiplication of R. dalhousiae in a limited time.

Plant Genetic Resource Division, Tropical Botanic Garden and Research Institute, Palode, Trivandrum 695 562, Kerala, India.

DOI: https://doi.org/10.37855/jah.2010.v12i01.09

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Abstract: An efficient and repeatable micropropagation protocol has been established for Amomum hypoleucum, a lesser known threatened medicinal plant of the family Zingiberaceae. Eighty percent of the rhizome nodes from greenhouse grown plants, cultured on MS medium supplemented with 1 mg L^-1 BA and 0.5 mg L^-1 IAA, showed axillary bud break in 8-10 days. Multiple shoots proliferated from such shoot explants when transplanted to medium with 3 mg L^-1 BA and 1 mg L^-1 TDZ. An average of 9.2 shoots could be recovered in two months and about 65-70% of the shoots showed simultaneous rooting. Isolated shoots were also rooted in medium fortified with 0.5 mg L^-1 NAA. Plantlets, transferred to the field after acclimatization in greenhouse conditions, showed 85% survival.

Agricultural Research Institute, Ministry of Agriculture, Natural Resources and Environment, P. O.Box 22016, 1516Nicosia, Cyprus.

DOI: https://doi.org/10.37855/jah.2010.v12i01.10

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Abstract: Lettuce plants (Lactuca sativa L. cv. 'Paris Island') were grown in an unheated plastic greenhouse to determine the effects of solution nitrogen concentration and growth regulators (gibberellin and kinetin) on growth (fresh and dry head weight) and tissue nitrate content (TNC). The plants were grown in plastic containers with perlite and supplied with a basic nutrient solution supplemented with nitrogen (N) corresponding to 50, 100, 150, and 200 ppm NO₃-N. Growth regulators; gibberellin (GA₃) and kinetin were applied at different doses independently and in combination. Fresh, dry weight and TNC were responsive to N application level. However, fresh and dry weights were similar at 150 and 200 ppm and TNC at 100 and 150 ppm nitrogen supply. Gibberellin (GA₃) and gibberellin and kinetin in combination (GA₃+kinetin) enhanced fresh and dry weight and TNC compared to the control. There were few differences in response to application rates. Therefore, where lettuce plants are grown in similar conditions and low NO₃ accumulation is desirable, together with high yield and good size, the best N application level is 150 ppm NO₃-N and growth regulators application may enhance yield. However their use in reducing the nitrate content is not recommended.

The University of the West Indies, Department of Food Production, Faculty of Science and Agriculture, St. Augustine, Trinidad, West Indies.

DOI: https://doi.org/10.37855/jah.2010.v12i01.11

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Abstract: The process of ripening was evaluated in three papaya cultivars, Solo Sunrise (SS), Tainung #2 (T2) and Red Lady (RL) with different mean fruit weights of 387, 1364 and 2266 g and fruit cavity void volumes of 56, 334 and 502 mL and fruit weight/cavity void volume ratios of 6.9, 3.8 and 4.3 g mL^-1, respectively. The evaluation was done by comparing physiological determinants of the ripening process; ethylene (C₂H₄) generation and respiratory CO₂ production, measured at two temperature ranges, 20-22^oC and 28-30^oC, by sampling cavity void volumes, with physico-chemical quality characteristics of ripening: skin colour, flesh firmness and pH. Fruit ripening of the three cultivars was delayed at the lower temperature range as measured both by physiological determinants including pre-and peak climacteric rates and physico-chemical quality characteristics. However, cv RL showed slower ripening than cvs SS and T2 at both temperature ranges, probably partly related to its low fruit weight/cavity void volume of 4.3 g mL^-1. Moreover, there were negative temporal displacements for skin degreening compared with those for flesh softening, respiration and ethylene generation in fruit of the three cultivars. Fruits of cvs SS and T2 were fully ripened in 8 days after harvest (DAH) and RL fruits in 10 DAH at the lower temperature range. Values for C₂H₄ generation and CO₂ production measured in the fruit cavity are judged to be sensitive indicators of the progress in the process of ripening.

Department of Horticulture, Chamran University, Ahvaz, Iran, Safiabad- Dezful Agricultural Research Center, Dezful, Iran.

DOI: https://doi.org/10.37855/jah.2010.v12i01.12

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Abstract: Yield of fruit tree is determined primarily by flowering intensity and subsequent fruit set. Flower number and fruit set are also influenced by endogenous nitrogen level. This research was concerned with the effect of winter foliar application of urea on flowering and fruit-set of 30-year-old 'Valencia' orange on sour orange rootstock at Safiabad Agricultural Research Center of Dezful. Treatments included urea foliar application at 3 levels (0, 0.5, 1%) and 2 times of application (6 and 9 weeks before full bloom). The experimental design was a factorial randomize complete block with 4 replications. Nitrogen percentage in leaf, flower number, ovary diameter and fruit set were studied. Results showed that winter application of urea increased the level of N for 2 weeks. Different levels of urea increased the number of flowers, ovary diameter and fruit set. The higher concentration of urea (1%) had more effect. Considering the time of application, urea spray 9 weeks before full bloom had the highest effect on flowering but urea spray 6 weeks before full bloom resulted in higher ovary diameter and fruit set.