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A 2-year greenhouse study was conducted at Clemson University, Clemson, S.C., in 2003 and 2004 to determine drought responses of six bermudagrass (Cynodon spp.) cultivars at four irrigation intervals. Cultivars selected from the 2002 National Turfgrass Evaluation Program Bermudagrass Trial were `SWI-1012', `Arizona Common', `Tift No.3', `Tifsport', `Aussie Green', and `Celebration'. Treatments included 5-, 10-, and 15-day irrigation intervals plus a control (irrigated daily). Volumetric soil water content (VSWC) and evapotranspiration (ET) rates were recorded every 3 days. Turfgrass quality (TQ) was observed weekly and root weight was measured at the end of a 6-week study. `Aussie Green' and `Celebration' produced the highest TQ rating (>7) at week 4 when watered daily. After 4 weeks of the 5-day irrigation interval, all cultivars showed unacceptable quality ratings (<7). However, `Aussie Green' and `Celebration' were able to maintain an acceptable TQ rating (7), compared to `Arizona Common' (5.1) and `Tift No.3' (5.8) at week 2 (5-day treatment). `Celebration' produced 114% and 97% greater root weight than `Tifsport' and `Aussie Green', respectively, when pooled across all irrigation treatments. At the 15-day irrigation interval treatment, six bermudagrass cultivars pooled together produced 78%, 22%, and 11% greater root weight vs. control, 5-day, and 10-day treatments, respectively. When pooled for all treatments, `Aussie Green' and `Celebration' VSWC was 5% and 7% lower than `Tift No.3', and ET rates were 26% and 30% greater than `Arizona Common'. Based on these results, irrigating bermudagrass in 5-day intervals should be carefully monitored.
Abstract
This study was designed to determine the effect of pest control intensity on net returns in multiple cropping systems. The study is tempered with an evaluation of risk. The cropping system encompasses: turnip greens (Brassica rapa L.) for processing, field corn (Zea mays L.), and southern peas [Vigna unguiculata (L.) Walp. ssp. unguiculata] for processing. Within the ranges of pest control intensities studied, less intensive control resulted in higher net returns. Further, the level of greatest pest control intensity consistently yielded negative net returns. This level, however, was less risky in terms of gross returns. Risk did not differ significantly between the other levels of pest control.
Abstract
Seeds of onion (Allium cepa, L.) were sown on 2 muck soils that were high and low in available phosphorus and which contained an indigenous population of mycorrhizal spores (Glomus sp.). Treatments were 4 levels of P (0, 30, 97, and 193 kg/ha) and inoculum of the mycorrhizal fungus Glomus etunicatus Becker & Gerdemann. In the soil that was low in available P (3 kg/ha) bulb weight increased with added P. Root infection by the mycorrhizal fungus and mycorrhizal spore numbers in the soil were negatively correlated with added P. Bulb weight and mycorrhizal spore number at harvest increased when mycorrhizal inoculum was added to the soil. In the soil that was high in available P (97 kg/ha) bulb weight, root infection, and spore numbers were not influenced by added P or added mycorrhizal inoculum. Root infection data from both soils suggested a threshold level of soil P below which mycorrhizal infection was high and above which infection was low. The levels of P commonly added to muck soils may negate any usefulness of mycorrhizae but addition of P might be reduced if mycorrhizal spore numbers were increased through inputs of mycorrhizal inoculum or cultural practices.
Abstract
‘Doreen’ is a bronze muscadine grape (Vitis rotundifolia Michx.) that can be made into wine equal in quality to ‘Carlos’ and ‘Scup-pernong’. It is self-fruitful, high-yielding, vigorous, resistant to berry shatter, adapted to mechanical harvesting with 50–60% dry fruit stem scars, winter-hardy in the southeast, and is generally disease resistant, including Pierce's disease. It requires 125 days from full bloom to harvest, compared to 100 days for ‘Carlos.’ It ripens in September in south Mississippi and Florida, and in October in North Carolina and north Mississippi.
Abstract
‘Sir Prize’ is a yellow, russet-free apple with immunity to apple scab caused by Venturia inaequalis (Cke.) Wint. The fruit is large and ripens along with ‘Golden Delicious’. It is released as a home garden cultivar.
Abstract
The response of rabbiteye blueberry plants (Vaccinium ashei Reade) to rates and modifications of deep well water (pH 8.7) containing 0.695 dS·m-1 electrical conductivity (EC), a sodium adsorption ratio (SAR) of 29.7, and a bicarbonate concentration of 7.89 meq·liter-1 was compared to plants irrigated with rain and surface waters applied to 3 soils in a glasshouse-container study. Fresh weight increase and root fresh and dry weight were greater on plants irrigated with rainwater or pond water compared to plants irrigated with different rates of deep well water, or deep well water modified by the addition of gypsum or acidified with H2S04. Fresh weight increase, root fresh and dry weight, leaf fresh weight, and top:root ratios were higher on a loamy sand soil than on sandy loam or clay loam soils. Plant weight gain was positively correated with the percentage of sand, and negatively correlated with the percentage of clay and saturation-extract SAR. An increase in soil pH resulted from irrigation with deep well water which, along with its modifications, resulted in increased leaf Na and decreased leaf Ca and Mn, compared to rain or surface-water irrigations, which slightly lowered soil pH.
Abstract
The performance of the mung bean cultivar Thai Green Oil was compared with the soybean cutivar Hsih-Hsih over a range of 12 plant densities from 10,000 to 800,000 plants/ha. Increasing plant density was positively related to yield and plant height and negatively related with significant reductions in flowering, yield per plant and plant branching. The higher yield potential of soybeans at high plant densities, relative to mung bean, was attributed to differences in the production of the number of flowers per plant and, subsequently, the number of pods per plant. This relationship can be applied to breeding and selecting improved mung bean cultivars.
The aim of the present work was to establish appropriate conditions for the in vitro micropropagation of Eremanthus erythropappus (DC.) MacLeish through shoot multiplication on apical and nodal bud explants. Explants were excised from in vitro-grown seedlings and incubated on Murashige and Skoog medium containing different combinations of 6-benzylaminopurine (BAP) and 1-naphthalene acetic acid (NAA) (for apical buds) and gibberellic acid and NAA (for nodal segments). Proliferation of apical shoots was successfully achieved in the presence of BAP and NAA, each at 1.0 mg L−1, while the elongation of apical shoots could only be attained on medium containing NAA at 1.0 mg L−1. Elongation of nodal shoots was induced in the presence of NAA at 2.0 mg L−1. The most suitable medium for inducing root proliferation on explants of E. erythropappus was NAA at 1.0 mg L−1.