Search Results

You are looking at 1 - 10 of 354 items for :

  • ground spot x
Clear All
Free access

Edgar L. Vinson III, Floyd M. Woods, Joseph M. Kemble, Penelope Perkins-Veazie, Angela Davis and J. Raymond Kessler

predictor, of fruit maturity ( Kano et al., 2008 ; Young et al., 1993 ). A number of subjective systems have been used by growers, including ground spot yellowness, senescent tendril next to the fruit pedicel, change in fruit wax (loss of shine), and

Free access

Rita Giuliani, Eugenio Magnanini and Luca Corelli Grappadelli

This work proposes a methodology, by light-scanning below the canopy, to directly estimate the photon flux radiation (400–1200 nm) intercepted by single or row canopies. The system is based on the assumption that the light intercepted by the canopy, at a particular time, corresponds to the difference between the incoming potential radiation on a ground surface area (able to include the ground area shaded by the canopy), and the actual radiation influx to that area in presence of the canopy. To this purpose, light-scanning equipment has been designed, built, and tested, whose main components are two aligned multi-sensor bars (1.2 m long) and a CR10 data logger, equipped with an AM 416 Relay Multiplexer (Campbell Sci. Ltd., U.K.). The radiation sensors (BPW 14N TELEFUNKEN) were chosen because of their spectral sensitivity, along with low cost. The sensors have been placed along the bars, at 5-cm intervals, and fitted with a Teflon® diffuser to provide a cosine correction. Radiation measurements are taken moving parallelly the bars on the ground, step by step, to monitor a sample point grid (5 cm by step length). Preliminary radiation scans were taken during the summer in a 3-year-old peach orchard, trained as delayed vasette. Measurements were taken for a single canopy at various hours of the day. Moreover, radiation scans were taken at the same hour, over a 3-day timespan, while gradually defoliating the canopy. A custom-built software program has been developed for data handling. Mathcad software (Mathsoft Inc., U.S.) has been used to display the canopy shade image projected on the ground, the quantum map of the monitored area, and to calculate the light influx on the whole canopy. Moreover, the light spots on the ground determined by foliage gaps have been identified and the amount of radiation reaching the ground has been be estimated.

Free access

Antonio O. Lessa, Luis A.S. de Castro and Gerson R. de L. Fortes

The purpose of this study was to adapt an ELISA test for diagnosing of “Apple Chlorotic Leaf Spot Virus” (CLSV) in apple trees. This work was carried out at Centro de Pesquisa Agropecuária de Clima Temperado–CPACT/EMBRAPA, Pelotas–RS, Brazil, during the 1996 spring season. The application of ADGEN Diagnostic Systems protocol does not give some positive results from diseased apple trees. The procedure modified by FLEGG & CLARK (1979) gives an unsatisfactory result for color reaction in the positive samples. It means it is necessary to adapt this methodology. When the antigen was obtained from leaves grown from the base to the intermediate position in the stem and grounded with extracting buffer—0.02 M, pH 7.4 (1 g tissue: 3 ml extracting buffer) and polyclonal antisera and antibody alkaline phosphatase conjugate was diluted in coating buffer—0.05 M, pH 9.6 (1 μg antisera or antibody: 500 μl coating buffer) the reaction become more intensive and the test was able to diagnosticate the presence of the pathogen in infected leaves of apple trees.

Free access

P. Perkins-Veazie and J.K. Collins

The red flesh of watermelon contains lycopene, a pigment with antioxidant properties that help prevent certain types of cancers. This experiment was done to determine cultivar variation in lycopene content, and the effectiveness of colorimetric measurements for predicting lycopene content. Ten ripe melons per cultivar of hybrid, open-pollinated, and triploid types were selected from field plantings at Lane, Okla. Melons were cut transversely and color measured with a colorimeter at three heart and three locule sites, in a counterclockwise rotation starting at the ground spot. For lycopene content, a 100-g sample of heart tissue was removed, extracted with a hexane-acetone-ethanol mixture, and lycopene concentration measured spectrophotometrically at 503 nm. Lycopene content varied among cultivars, from 33.96 μg·g–1 in `Crimson Sweet' to 66.15 μg·g–1 in `Crimson Trio'. Chroma and “a” colorimeter values were highly correlated with lycopene content (P < 0.001). Linear and quadratic regression of lycopene against colorimeter values yielded an R 2 of 0.55. Results indicate that, like tomatoes, watermelon cultivars vary widely in lycopene content. Colorimeter readings did not adequately predict lycopene values.

Free access

Gabriele Gusmini and Todd C. Wehner

Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] is a diverse crop, with much variability for fruit and seed traits. This study measured the inheritance of scarlet red flesh color, egusi seed type, yellow belly (ground spot) rind pattern, and intermittent stripes on the rind. Scarlet red is a dark red flesh color found in `Dixielee' and `Red-N-Sweet'. Egusi seed is an unusual mutant having a fleshy pericarp adherent to the seed coat found in PI 490383 and PI 560006. Yellow belly is found in `Black Diamond, Yellow Belly'. Intermittent stripes are found in `Navajo Sweet', which has narrow dark stripes that are irregular or nearly absent across the fruit. In order to study the inheritance of these traits, six generations, including parents, crosses, and backcrosses (Pa, Pb, F1, F2, BC1Pa, BC1Pb), were produced in each of seven crosses. Phenotypic data were recorded in the field, and analyzed with the Chi-square method for the segregation of Mendelian genes. Scarlet red color in `Dixielee' was allelic to scarlet red color in `Red-N-Sweet'. Four new genes were identified and named, in conformance with gene nomenclature rules for Cucurbitaceae: Scr for scarlet red, eg for egusi seed, Yb for yellow belly, and ins for intermittent stripes. Thus, we have added four new genes to the 52 morphological and disease resistance genes already published.

Full access

Emily E. Braun, Sarah Taylor Lovell, Mohammad Babadoost, Frank Forcella, Sharon Clay, Daniel Humburg and Sam E. Wortman

each grit type and applicator by weighing grit in the hopper before and after application in each plot ( Table 1 ). Table 1. Average application rates for one field pass of each grit type, application method (spot spray in the crop hole vs. continuous

Full access

Gary E. Vallad and Bielinski M. Santos

in tomato. Florida accounted for nearly 40% of the total U.S. gross sales ( USDA, 2010 ). Among the many diseases that affect tomato, bacterial spot is one of the most troublesome ( Bouzar et al., 1999 ; Jones et al., 2004 ; O'Garro and Charlemagne

Full access

Jozer Mangandi, Sydney Park Brown and Natalia Peres

incorporated into the upper 6 inches of soil. Plants were placed 8 ft apart on 8-ft-wide beds covered with ground cloth topped with a 4-inch layer of fine ground pine bark mulch. The irrigation regime included an establishment period providing water by drip

Free access

Suping Zhou, Roger J. Sauvé, Zong Liu, Sasikiran Reddy, Sarabjit Bhatti, Simon D. Hucko, Yang Yong, Tara Fish and Theodore W. Thannhauser

frozen in liquid nitrogen. Preparation of protein samples and differential two-dimensional fluorescence gel electrophoresis. To extract protein, frozen leaf tissues were ground into a fine powder and mixed into acetone containing 10% trichloroacetic acid

Free access

Sarah M. Smith and Zhanao Deng

to 2008. Inheritance study of morphological traits. Our preliminary studies showed that COLE and COTI differ obviously in three morphological characters, trichomes on the leaf petioles, the maroon spot on the ray flowers ( Fig. 1 ), and seed