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contained in the experimental unit to combine several traits of economic interest ( Cruz et al., 2012 ). This study aimed to estimate the predicted genetic gains with the simultaneous selection of yield traits and soluble solids content in cherry tomato

Open Access

reallocation in existing tissues or nutrient uptake ( Bryla and Strik, 2015 ). Nutrients are also lost when fruit are harvested, leaves senesce, and plants are pruned. Gains and losses in nutrients have tended to follow the same pattern of DW in blueberry and

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Several major traits (yield, earliness, quality) of interest to cucumber (Cucumis sativus L.) breeders are quantitatively inherited. The objective of this study was to determine the progress made on such traits using recurrent selection in 4 fresh-market cucumber populations (NCWBS, NCMBS, NCES1, NCBA1). During population improvement, 1 to 2 replications of 200 to 335 half-sib families were evaluated for 5 traits: total, early and marketable fruits per plot, a quality rating, and a simple weighted index (=.2Total/2 + .3Early + .2%Marketable/10 + .3Quality). Families from each population were intercrossed in an isolation block during each summer using remnant seeds of the best 10% selected using the index. Progress was evaluated using a split-plot treatment arrangement in a randomized complete block design with 32 replications in each of 2 seasons (spring and summer). Whole plots were the 4 populations, and subplots were the 11 cycles (cycles 0-9 plus checks). Greatest gains were made for the NCBA1 population, with an average of 45% gain from cycle 0 to 9 over the 5 traits, and for early yield, with an average of 58% gain from cycle 0 to 9 over the 4 populations. Populations were improved for performance in a selected (spring season) as well as a non-selected environment (summer season).

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Abstract

A method is presented to calculate net heat gain per unit time (G) for normal (N) and for whitewashed (W) cantaloupe fruits (Cucumis melo, L., var. reticulatus Naud.) exposed to direct solar radiation. Calculations of G were based on pulp temp. G of the W fruits averaged 80% of that for the N fruits during warming. Values of G can aid in evaluating the effectiveness of radiation-reflective materials that protect cantaloupe fruits from sunburn, a major cause of culls and market quality losses. Maximum pulp temp about 1 mm below the surface reached 49°C for the N and 42° for the W fruit. Maximum ambient air temp was 43°C.

Open Access

Abstract

Evidence from 3 experiments supports the hypothesis that beyond the critical leaf area index (LAI), the rate of dry weight gain is the same for Chrysanthemum morifolium Ramat. cv. Bright Golden Anne grown at either normal (15.6°C) or low (5.6°) night temperature, providing that conditions during the 8 hour light period are the same. The term “critical LAI” is suggested as the LAI at which the curve for rate of dry weight gain as a function of LAI assumes a slope approaching zero. Hence, with appropriate management of LAI, the productivity per unit area of greenhouse devoted to this crop could be as great at 5.6° as at 15.6° night temperature, despite the delay of maturation for plants grown at low night temperature.

Open Access

Leaf and whole plant gas exchange (net photosynthesis Pn, dark respiration Dr, transpiration Tr, and resistance R) of `Jacqueline' Alstroemeria, grown in pots inside a greenhouse, were measured under lab conditions using an openflow and a semi-closed system respectively.

Temperature responses of apical fully expanded leaves, on flowering and non-flowering shoots, showed an optimum range for net photosynthesis (Pn) from 15 to 20 °C. Above 25 °C Pn dropped considerably as temperature increased. Leaf transpiration rates over the same range of temperature showed a similar decrease, indicating that low leaf Pn rates at higher temperatures were due in part to increased stomatal resistance.

Whole plant photosynthetic response to temperature was similar to that of leaf gas exchange. The optimum temperature range for whole plant Pn was from 12 to 17 °C. These results show that moderately low temperatures are essential for carbon assimilation and efficient water use in Alstroemeria. Temperature interactions with other environmental factors will also be presented in models describing Pn rates as a function of irradiance, CO2 concentration, and temperature.

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This paper summarizes the management framework, organizing plan, and results of a multi-state, multi-institutional partnership delivering a targeted “train-the-trainer” program addressing food chain security in the southeastern U.S. The partnership provided good agricultural practices (GAPs) and good manufacturing practices (GMPs) –based training to fresh fruit and vegetable (produce) growers and packers throughout the region. Twelve southern states cooperated in this project: Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia. This 2000–04 work was funded by National Food Safety Initiative grants. Although proposed long before events of 11 Sept. 2001, the project and its results are increasingly relevant since that time. This is because consumer expectations regarding the nation's food supply now include a new security consciousness addressed in this project.

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Temperature and chlorophyll fluorescence characteristics were determined on leaves of various horticultural species following a dark adaptation period where dark adaptation cuvettes were shielded from or exposed to solar radiation. In one study, temperature of Swietenia mahagoni (L.) Jacq. leaflets within cuvettes increased from ≈36C to ≈50C during a 30-minute exposure to solar radiation. Alternatively, when the leaflets and cuvettes were shielded from solar radiation, leaflet temperature declined to 33C in 10 to 15 minutes. In a second study, 16 horticultural species exhibited a lower variable: maximum fluorescence (Fv: Fm) when cuvettes were exposed to solar radiation during the 30-minute dark adaptation than when cuvettes were shielded. In a third study with S. mahagoni, the influence of self-shielding the cuvettes by wrapping them with white tape, white paper, or aluminum foil on temperature and fluorescence was compared to exposing or shielding the entire leaflet and cuvette. All of the shielding methods reduced leaflet temperature and increased the Fv: Fm ratio compared to leaving cuvettes exposed. These results indicate that heat stress from direct exposure to solar radiation is a potential source of error when interpreting chlorophyll fluorescence measurements on intact leaves. Methods for moderating or minimizing radiation interception during dark adaptation are recommended.

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