Search Results

You are looking at 1 - 10 of 134 items for

  • Author or Editor: L. Smith x
Clear All Modify Search
Author:

Emergence of snap beans (Phaseolus vulgaris L.) in field soil in 1993–95 was enhanced by the biocontrol agent Gliocladium virens J.H. Miller, J.E. Giddens, & A.A. Foster. The fungus was applied to each seed at planting as a wheat bran alginate pellet formulation in 1993–95. Preemergence and postemergence damping-off were reduced in plots treated with G. virens. Nodulation on the roots of treated plants was numerically increased in 1993 and 1994 compared to nontreated plots. Efficacy of G. virens was reduced in 1995, probably due to high ambient temperatures at the time of planting. In plots with reduced stand, leaf area was increased and yield on a per-plant basis was larger than in plots with a better stand. Total yield also was increased in plots with fewer plants, except in 1994. Fungi isolated from failed seedlings included Fusarium spp., Pythium spp., and Rhizoctonia solani Kühn.

Free access
Author:

Emergence of snap beans (Phaseolus vulgaris L.) in field soil in 1995 to 1997 was reduced by the addition of dried, ground canola [Brassica napus L. ssp. oleifera (Metzg.) Sinsk. f. biennis] leaves and petioles to the furrow at planting. Soil amendment with the tissue increased the number of nodules on bean roots in all years. In plots with reduced stand, leaf area was increased and yield on a per-plant basis was larger than in plots with a better stand. Total yield was increased in plots with fewer plants only in 1995. Frequency of isolation of fungi that cause damping-off was not affected by the addition of canola at planting. When used as a seed treatment and incorporated at planting, canola residues were detrimental to emergence of snap bean.

Free access

Abstract

Fruit of ‘Earliglow’ (Fragariaananassa Duch.) showed a significantly low incidence of postharvest rot caused primarily by Botrytis cinerea Pers. ex Fr. in 2 years of testing. Incidence of rot was modified by environmental factors during postharvest storage, particularly by cold storage.

Open Access
Authors: and

Four-year-old `Redblush' grapefruit (Citrus paradisi Macf.) trees on either the relatively fast-growing rootstock `Volkamer' lemon (VL) (C. volkameriana Ten. & Pasq.) or on the slower-growing rootstock sour orange (SO) (C. aurantium L.) were transplanted into 7.9-m3 drainage lysimeter tanks filled with native Candler sand, irrigated similarly, and fertilized at three N rates during 2.5 years. After 6 months, effects of N application rate and rootstock on tree growth, evapotranspiration, fruit yield, N uptake, and leaching were measured during the following 2 years. When trees were 5 years old, low, medium, and high N application rates averaged about 79,180, or 543 g N/tree per year and about 126,455, or 868 g N/tree during the following year. Recommended rates average about 558 g N/tree per year. A lysimeter tank with no tree and additional trees growing outside lysimeters received the medium N treatment. Nitrogen concentration in the drainage water increased with N rate and exceeded 10 mg·liter-1 for trees receiving the high rates and also for the no tree tank. Leachate N concentration and total N recovered was greater from trees on SO than from those on VL. Average N uptake efficiency of medium N rate trees on VL was 6870 of the applied N and 61 % for trees on SO. Nitrogen uptake efficiency decreased with increased N application rates. Trees outside lysimeters had lower leaf N and fruit yield than lysimeter trees. Overall, canopy volume and leaf N concentration increased with N rate, but there was no effect of N rate on fibrous root dry weight. Fruit yield of trees on SO was not affected by N rate but higher N resulted in greater yield for trees on VL. Rootstock had no effect on leaf N concentration, but trees on VI. developed larger canopies, had greater fibrous root dry weight, used more water, and yielded more fruit than trees on SO. Based on growth, fruit yield and N leaching losses, currently recommended N rates were appropriate for trees on the more vigorous VL rootstock but were 22% to 69 % too high for trees on SO.

Free access

The first four chapters of a hands-on gardening curriculum (Junior Master Gardener Handbook Level One) were introduced into three East Baton Rouge Parish (Louisiana) elementary schools in the fall semester of 2002 as an informal education program conducted by East Baton Rouge Parish Master Gardener volunteers and Louisiana State University students. The curriculum took place once per week for 2 hours during regular school hours. Science achievement tests, developed at Texas A&M University specifically for the Junior Master Gardener program, were given before and after the students participated in the gardening activities to determine whether or not the activities helped improve achievement scores. Science achievement was significantly different (P ≤ 0.0167) between the experimental classes' pretest and posttest scores, while no significant difference was found between the pretest and posttest scores of the control classes. No significant difference was found between the experimental and control classes due to treatment. Several variables may have affected the outcome of the study, but the results show once weekly use of gardening activities and hands-on classroom activities help improve science achievement test scores.

Full access

Experiments were conducted to estimate the relative importance of additive and dominance genetic variances and non-allelic interactions in the inheritance of resistance to Colletotrichum spp. in strawberry (Fragaria × ananassa Duch.). Progeny of 40 parents crossed in a Comstock and Robinson Design II Mating scheme were inoculated with three isolates of C. fragariae and one isolate of C. acutatum. Disease development on each plant was rated visually. Variance components were estimated and converted to genetic variances. Estimates of were six to 10 times higher than those for Within-family variance not accounted for by equaled 35% and 38% of the total genetic variance in females and males, respectively, indicating probable epistatic effects. The frequency distribution of disease severity ratings was bimodal in both experiments, suggesting major gene action. Narrow-sense heritability estimates were 0.37 and 0.26, and broad-sense heritability estimates were 0.87 and 0.85 for females and males, respectively. Narrow-sense heritability estimates are probably sufficient to produce gains from recurrent selection. Gains from selection of clonal value should be possible because of the high broad sense heritability estimates. It appears feasible to establish a broad genetic-based population resistant to Colletotrichum spp. from which selections could be evaluated per se and/or recombined to produce improved populations.

Free access

Abstract

The relationship between net CO2 assimilation rate (A) and nitrogen (N) content during leaf senescence was determined on field grown Vitis vinifera L. ‘Thompson Seedless’ leaves. Measurements commenced subsequent to fruit harvest and were made at weekly intervals until leaf fall. Maximum A was greater than 2.0 nmoles CO2 cm-2s-1 when leaf N content was greater than 3.0%. There was a linear relationship between A and percent N content regardless of whether A was expressed on an area or dry weight basis. However, the correlation between A on a dry weight basis and percent leaf N was greater than that between A on an area basis and percent leaf N. The percent N content and net CO2 assimilation rate decreased as weight per unit leaf area (W) increased. There was no effect on leaf N content on stomatal conductance (gs) when N content was greater than 2%. The results suggest that leaf N content could be used an as indicator of a grapevine's leaf photosynthetic capacity subsequent to fruit harvest.

Open Access
Author:

Soils, entomology, forestry and horticulture faculty were combined into a single merged Department of Natural Resources and Environmental Sciences (NRES) during a recent College of Agriculture, Consumer, and Environmental Sciences restructuring process at the University of Illinois. The merger initially spawned multiple concerns from faculty, but after an adjustment period, ultimately resulted in enhanced organization, accountability, and collaboration. New, multidisciplinary initiatives within NRES, such as the Illinois Green Industry Survey or development of a highly successful off-campus masters program, attest to the fact that the merger brought new strength and expanded opportunities to our unit.

Full access
Author:

Abstract

University horticulture students often do not experience the real challenges of the industry until after graduation due to the constraints of classroom schedules and the traditional lecture/laboratory format (3, 10). Practical management of a nursery inventory is a classic example. Complete inventory records are essential for making key management and planning decisions in any business, but the peculiar traits of a woody plant materials inventory demand exceptional ingenuity on the part of nurserymen. Nursery stock may remain in inventory for 7-10 years (from propagation to sale), and is continually changing (in terms of size and caliper) during this period. Individual plants are moved through multiple production stages with characteristic production losses at each stage, a complication that requires constant updates in inventory records. The long lag time between propagation and finished production also makes the target market and number of plants ultimately available for sale very difficult to predict accurately. Each unique requirement compounds the difficulty of maintaining a useful nursery stock inventory record.

Open Access
Author:

The bright red pigmentation in edible, anthocyanin-rich fruits and vegetables is a definite bonus in terms of market appeal. As a result, breeders have worked consistently to intensify anthocyanin levels or alter composition in crops. The positive links between consumption of crops and food products containing natural anthocyanin pigments, and reduced incidence of cardiovascular and other chronic diseases, have been established anecdotally and more recently validated in research trials including those from our laboratory group. The protective events, most attributed to the potent antioxidant properties of anthocyanin pigments and associated phytochemicals, place anthocyanin-rich crops in the category of “Functional Foods,” yielding health protection unrelated to nutritional value. In vitro bioactivity assays have identified components from these crops capable of blocking the initiation stages of carcinogenesis, while a completely separate class of phytochemicals and sets of assays establish efficacy against the promotion stages of tumorigenesis. Animal models for carcinogen-induced damage to mammary gland and skin DNA subsequently demonstrate the in vivo potency of the same target compounds. Similarly, to establish cardioprotective properties, demonstrations of ability to inhibit platelet aggregation, relax vascular muscle tissue, and reduce total serum cholesterol are demonstrated in a series of in vitro assays, and via animal models and human studies. While activity-directed fractionations seek to identify specific responsible compounds, it is increasingly evident that bioactivity is drastically attenuated once specific compounds are isolated, and the synergistic interaction of associated phytochemicals in horticultural crops is prerequisite to realizing health benefits. These complications have slowed the establishment of effective minimum “dosages,” but all the more strongly promote consumption of the crops.

Free access