Browsing by Author "Waterer, D."
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Item Abscisic acid analogues for enhanced stress tolerance and size control of tomato seedlings(2001-02-22) Sharma, N.; Abrams, S.R.; Waterer, D.Transplanting shock is a common problem during establishment of horticultural crops like vegetables and ornamental bedding plants. The marketing period of nursery raised seedlings is limited due to the loss of aesthetic quality associated with undesirable growth and accelerated moisture loss during storage and handling. Two synthetic analogues (PBI 365 and PBI 429) of the plant hormone abscisic acid (S. Abrams PBI/NRC) were evaluated in a number of greenhouses and field trials at the University of Saskatchewan, for their potential to alter the stress tolerance and growth of horticultural crops. Pre-planting application of analogues, at 10-4 M, enhanced the tomato transplants survival under moisture stress in field conditions. Under greenhouse conditions, the ABA analogues slowed the moisture use and growth of seedlings without deteriorating the visual quality. Thus, ABA analogues could be used in horticultural crops for enhanced stand establishment as well as to hold seedlings at a particular stage thereby allowing their storage and extending the marketing period.Item Calcium amendment and NaCl salt pre-treatment improves salinity tolerance in potato genotypes(2008-02-28) Etehadnia, E.; Waterer, D.R.; Tanino, K.K.Pre-exposure to low but non-toxic levels of calcium and NaCl salt have been demonstrated to ameliorate the adverse effects of subsequent NaCl stress on plant growth and nutrient uptake. The effect of CaCl2, NaCl and CaCl2 + NaCl on subsequent salt stress tolerance, growth, water status and ion accumulation of four contrasting potato genotypes, 9506, ‘Norland’, ABA-deficient mutant and ABA normal sibling were investigated to provide an additional tool to induce NaCl salt stress tolerance. NaCl pre-treatment was generally the most effective in inducing salt stress resistance reflected by positive response measurements in all genotypes. ‘Norland’ and ‘9506’ enhanced growth up to 70% via root mass under salt stress and expressed elevated water status under NaCl pre-treatment, possibly via Na+ accumulation in the roots. Unlike ‘Norland’, the 9506 genotype also tolerated the presence of Na+ in the shoot. However, NaCl was excluded from the shoot of ‘9506’ after CaCl2 pre-treatment and may indicate a genotype-dependent Ca+2 requirement for Na+ exclusion. In the ABA normal sibling, salt stress resistance was largely regulated by two mechanisms under all pre-treatments: a) shoot Na+ exclusion and root Na+ accumulation; b) enhanced water status which was expressed by an elevation of leaf and shoot water content. This response to pre-treatment was facilitated by: a 40% - 100% increase in root mass, enhanced K+ uptake into the roots, enhanced K+/Na+ ratio in the root and shoots and increased leaf osmotic potential. The ABA-deficient mutant expressed only one mechanism of salt stress resistance in response to pre-treatments in which leaf and shoot water content increased. That the pre-treatments of the ABA-deficient mutant were not able to adequately increase shoot K+ and exclude Na+ from the shoot relative to the ABA normal sibling and other genotypes suggests that ABA is a requirement for this mode of salt stress defence.Item Improving the harvestability of dry beans with gibberellic acid(1997-02-20) Wallace, T.; Hucl, P.; Waterer, D.; Vandenberg, B.; Slinkard, A.E.Currently beans (Phaseolus vulagris L.) are commercially harvested in several operations. Initially mature plants are cut below the soil surface by a bean puller, swaths are later windrowed, then picked up and threshed. Attempts to improve the efficiency of bean harvesting, using straight cut harvesters have been problematic due and the proximity of the pods to the ground. Yield losses during straight cut harvesting can range from 25-90%. Increasing stem length, thereby increasing the distance of pods from the ground, will permit the direct harvest of dry beans and reduce yield losses. The effects of gibberellic acid (GA) on the canopy structure and harvestability of three cuitivars (Othello, UI 906, and Aztec ( 1995 only)) were examined in the field. Trials were conducted at two locations in 1994 and 1995. Five rates of GA (0, 12.5, 25, 37.5, and 50 ppm) were applied at three growth stages ( 1 st, 2nd, and 3rd trifoliolate leaf stages). Mechanically harvested yields were compared to hand harvested yields to determine if treatments improved the percentage yield recovery with straight cut harvesters. Some cultivars were found to be more sensitive to GA treatment than others. Gibberellic acid stimulated internode elongation in all cultivars, stem length increases of 10% to 200% over control plants were recorded. One cultivar’s (Othello) harvestability was improved by very high concentrations of GA.Item Irrigation and seed piece spacing effects on potato seed-tuber yield(1997-02-20) Wahab, J.; Waterer, D.; Hogg, T.The seed potato industry is the most rapidly growing sector in the horticultural industry in Saskatchewan. The phenomenon of ‘Northern Vigour’ and the reduced levels of tuber-borne diseases and pests on the prairies make the Canadian prairies, including Saskatchewan, producers of high quality seed potato. This is reflected in the increasing exports of seed potato to the USA, Mexico, and other markets. In Saskatchewan, seed potatoes are grown both under dryland and irrigated conditions. Small tubers are preferred as seed potato relative to processing or table stock. Cultural practices suited to produce maximum yields of seed grade tubers (30-80 mm diameter tubers) are different from producing larger table or processing potatoes (>45 mm diameter tubers). The effects of moisture stress vary among cultivars. The different growth and tuberization characteristics of potato cultivars can further complicate management considerations such as fertility practices, plant population, etc. With steadily increasing input and other production costs, it is essential to develop appropriate, cultivar(s) specific, management practices to produce high quality (physiologically vigorous and disease-free) seed potato and to maximize economic returns. The Saskatchewan Irrigation Development Centre (SIDC) and the Department of Horticulture Science, University of Saskatchewan are jointly developing management practices to optimize yields of high quality seed potato. This project includes cultivars targeted for both domestic and export markets. Various aspects such as, land preparation, fertility requirement, seed piece spacing, irrigation scheduling, seed piece form/type, and plant population are being studied. This paper summarizes data from preliminary studies conducted during 1994 and 1995 at SIDC designed to examine irrigation and in-row seed piece spacing effects on seed grade tuber yield.Item Sap testing for fertility management in potatoes(1995-02-23) Waterer, D.Item Saskatchewan vegetable production – an opportunity awaits(2000-02-22) Green, O.; Vestre, B.; Tollefson, L.; Clark, H.; Waterer, D.At 7% “in-season” self sufficiency, Saskatchewan imports about $20,000,000 of fresh vegetables annually. To further exploit this apparent diversification opportunity a vegetable project was initiated in 1996 to demonstrate newer production technologies and to obtain data for Saskatchewan based costs of production. One half acre sized fields of pumpkin, carrots, cabbage, peppers, cucumber, broccoli, cauliflower, romaine lettuce, celery, Brussels sprouts and cantaloupe have been grown and marketed to simulate commercial production. The results have shown that acceptable yields of suitable quality produce can be grown and superior quality where proximity to market is a factor. Net returns have been positive for the most part but, since labour is such a significant component of variable costs, productivity and efficient use of labour can be critical. These initiatives have given the vegetable industry in Saskatchewan further impetus and direction. A number of new producers and a new generation cooperative, currently in the formative stages, appear poised to further diversify the agricultural landscape with SASK GROWN fresh vegetables.Item Saskatchewan vegetable production – an opportunity awaits(2001-02-22) Green, O.; Vestre, B.; Tollefson, L.; Clark, H.; Waterer, D.At 7% “in-season” self sufficiency, Saskatchewan imports about $25,000,000 of fresh vegetables annually. To further exploit this apparent diversification opportunity a vegetable project was initiated in 1996 to demonstrate newer production technologies and to obtain data for Saskatchewan based costs of production. One half acre sized fields of pumpkin, carrots, cabbage, peppers, cucumber, broccoli, cauliflower, romaine lettuce, celery, Brussels sprouts and cantaloupe have been grown and marketed to simulate commercial production. The results have shown that acceptable yields of suitable quality produce can be grown and superior quality where proximity to market is a factor. Net returns have been positive for the most part but, since labour is such a significant component of variable costs, productivity and efficient use of labour can be critical. These initiatives have given the vegetable industry in Saskatchewan further impetus and direction. A number of new producers and a new generation cooperative, currently in the formative stages, appear poised to further diversify the agricultural landscape with SASK GROWN fresh vegetables.Item Seed potato! A “vigorous” proposition for Saskatchewan(1996-02-22) Wahab, J.; Waterer, D.; Hogg, T.