No abstract

Many tomato growers face challenges in producing their crops due to stricter environmental regulations and fewer chemicals available for weed control. There is a demand for cultural practices that reduce chemical inputs and synthetic materials. Heirloom tomato varieties are becoming more popular among commercial tomato growers due to increased demand from consumers. Since most heirloom tomatoes at present are grown on small acreage, the addition of organic mulches may be a practice feasible for reducing chemical inputs for weed suppression. Heirloom tomatoes were grown using organic mulches (shredded newspaper, wheat straw and composted landscape bark) and an inorganic mulch (black plastic) plus a bare ground control to evaluate their effectiveness on heirloom tomato marketable yield and weed suppression. All treatments were grown with pre-emergence herbicide (high input) and without pre-emergence herbicide (low input). Marketable yields for the 10 treatments ranged from 3.4 to 50 MT/ha and 11.5 to 35.6 MT/ha in 2000 and 2001, respectively. Mulch x herbicide interactions were not significant for yield in either year. Mulches with and without herbicide inputs produced higher yields than unmulched plots in both years. Bare ground control with no herbicide inputs resulted in the lowest yields and highest weed densities and biomass. In an attempt to reduce chemical inputs for weed control in tomato production, organic mulching materials may be a viable option for vegetable growers.

Several factors can influence stand establishment in vegetable crop production. Environmental conditions such as soil physical characteristics, temperature and moisture, various cultural practices, and diseases may all be limiting factors in establishing maximum stands and achieving the highest possible yields. Measures taken to increase stands include soil improvements, implementing cultural practices, and use of chemical and biological seed treatments. Combining seed treatments and cultural/tillage practices to minimize environmental constraints can lead to maximum stands and yields in the production of high quality vegetable crops.

No abstract

Leaf impressions were made from two short-lived (4 and 5 d) inbreds, a longlived (11 d) inbred, and their hybrids (8 and 9 d) of Antirrhinum majus L. using Super Glue and glass microscope slides. Leaves were taken from mid stem, pressed on glass slides (under side down), spread with a small amount of Super Glue, set for 3 to 4 s. Then, the leaf was peeled off leaving a permanent impression in the glue. Slides were placed under a microscope equipped with a video imaging A phenol-sulfuric acid assay was used to quantify non-specific neutral carbohydrates in Antirrhinum majus L. flowering stems of three inbreds and their hybrids. Flowering stems 40 cm long were harvested with five to six florets open and flower, leaf, and stem tissue separated, freeze-dried, and finely ground. Carbohydrates were extracted from the tissue with 95% ethanol in a 70 °C water bath and combined with a 5% w/v phenol solution and concentrated sulfuric acid. Glucose equivalents were determined with a spectrophotometer at absorbance of 490 nm. Averaged over tissue type, results were genotype dependent, ranging from 213 to 291 µg glucose equivalent per mg dry tissue with a LSD 0.05 = 13. Flowers had the highest concentration of 340 µg/mg dry tissue, followed by stems, then leaves with 36% and 38% lower concentrations, respectively. Carbohydrate concentrations in two inbreds were compared when grown under cool (16 °C) and warm (29 °C) conditions. A genotype x environment interaction exists with inbred 3 exhibiting no reduction, 6% increase, and a 45% reduction in carbohydrate concentration when grown in warm conditions, while inbred 2 exhibited 15%, 23%, and 37 % reductions for flowers, leaves, and stems, respectively. Overall, there were 10% and 21% reductions in carbohydrate concentration for inbreds 2 and 3, respectively, when plants were grown under warm conditions. In an effort to determine the optimal light level for growing pawpaw [ Asimina triloba (L.) Dunal] seedlings outside, seedlings were germinated in a greenhouse until the two-to three-leaf stage, at which time they were placed outside and shade treatments were imposed that reduced incident light intensity by 30%, 55%, 80%, and 95%. Control seedlings were left unshaded outside. A randomized block design was used, with 20 replicate seedlings in each experimental treatment per block. Plants were destructively harvested 11 weeks after the start of the experiment. After 11 weeks, the height and number of leaves per seedling were about 35% higher with light to moderate shading (30%, 55%, and 80%) than in control (unshaded) seedlings. Shoot and leaf dry weights of seedlings grown in 30%, 55%, and 80% shade were almost 2-fold greater than control plants. Root dry weight of seedlings in 30% and 55% shade was 2-fold higher than in control plants. Total plant biomass was greatest in the 30%, 55%, and 80% shade treatments, about 2-fold higher than control plants. Total leaf area per seedling increased significantly with up to 80% shading. Seedlings growing under 95% shading had fewer and sma...