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2 VEGETABLE CULTIVAR AND CULTURAL TRIALS 2007 PREPARED BY: D. WATERER W. HRYCAN FUNDED BY: AGRICULTURE DEVELOPMENT FUND Department of Plant Sciences University of Saskatchewan, 51 Campus Drive Saskatoon, Saskatchewan, Canada, S7N 5A8 Telephone: (306) Fax: (306)

3 Vegetable cultivar evaluations and cultural trials are conducted annually by the Vegetable Program, Plant Sciences Department at the University of Saskatchewan as a service to the vegetable growers of Saskatchewan. The trials are made possible with financial support from the Agriculture Development Fund of Saskatchewan Agriculture, Food and Rural Revitalization, support from the Plant Sciences Department and with the support of grower cooperators and suppliers of horticultural products. Special thanks is extended to all personnel who helped with the planting, maintenance, harvest and analysis of vegetable cultivar evaluations and cultural trials. The data presented apply to specific growing conditions and production practices and may not be applicable under all conditions or practices. More detailed results on any trial may be obtained by contacting: Doug Waterer Department of Plant Sciences University of Saskatchewan 51 Campus Drive Saskatoon, SK S7N 5A8 Canada Ph: Fax:

4 Table of Contents 2007 Cultivar trials Introduction Cultivar recommendations 7 Seed suppliers 14 Recommended vegetable cultivars: Green beans 29 Red cabbage 31 Nantes carrots Yields 33 Root characteristics 37 Turnips 38 Corn Ornamental corn 39 Sweet corn 41 Supersweet corn 43 Garlic Cultivar trial 45 Storage trial (2006/2007) 46 Herbs Basil 47 Cilantro 49 Oregano/mint/other herbs 50 Green leaf lettuce 51 Onions Bunching onions 55 Yellow storage onions trial (2006/2007) 57 Spanish onions 59 Zucchini 60 Heirloom tomatoes Yields 63 Fruit characteristics 67 Watermelon Cultural trials Potato variety trials 77 Agronomy of new potato lines 79 Potential to use plant growth regulators to enhance the appearance of red-skinned potatoes 88 High tunnel project 93 Evaluation of biodegradable mulches 96 Mulching options for sweet corn and melons 103 Evaluation of coloured mulches 106

5 2007 Vegetable cultivar trials Introduction Vegetable cultivar trials are conducted annually by the Vegetable Program, Department of Plant Sciences at the University of Saskatchewan to supply Saskatchewan's vegetable growers with information on cultivar performance under local growing conditions. The 2007 trials were made possible by financial support from the Agriculture Development Fund of Saskatchewan Agriculture, Food and Rural Revitalization. The support of grower co-operators and suppliers of seed and horticultural products is also appreciated. Cultivars are selected for testing based on performance in previous trials, recommendations from other provinces, local growers, industry sources and seed companies. The results compiled in this bulletin are meant to aid growers in selecting cultivars which suit their market and production conditions. The data presented are specific to the prevailing growing conditions and production practices and may not be applicable to all farm sites. We wish to thank the following personnel for assisting in this study: Kyla Mamer, Barrett Blue, Laurie Thomson, Nick Assad, Neil LaBar, Darren Clauson and Jacqueline Bantle The 2007 trials were conducted on the Horticulture Field Station site, University of Saskatchewan, Saskatoon. Clay soil, ph = 7.4, E.C.<1.0 ds/m2 Sheltered site, long-term vegetable rotation Drip and overhead irrigation Production Practices Crop production and pest control measures generally followed recommended practices. Soil fertility levels were adjusted according to the recommendations outlined in the Horticulture Science Publication: "Vegetable Crop Fertility Schedules" (ERDA Publication No. 88-3). All crops received a mid-season application of nitrogen via side-dressing. Overhead or drip irrigation were used to maintain adequate soil moisture levels throughout the growing season for all crops. Bunching onions, red cabbage, Nantes carrots, cilantro, leaf lettuce, turnips, green beans, and sweet corn were direct seeded using a Planet Jr. type seeder. Carrots were seeded in twin 8m rows on raised beds with 10cm between the rows on each bed. The distance between raised beds was 1m. Carrot data were taken from 2m sections of row at three different harvest dates. Bunching onions, cilantro, leaf lettuce and turnips were planted in twin 8m long rows. Yield data were taken from a portion of each row, while the remainder of the row was used to evaluate 1

6 bolting tolerance. Sweet corn and beans were planted in twin 6m long rows and data were taken from the full length of the planted rows. Red cabbage was planted in twin 6m long rows. Each cabbage cultivar had a direct seeded row beside a machine transplanted row. At the same time that cabbage was direct seeded in the field, cabbage transplants were seeded into Sunshine Mix #4 in 50 cell trays in the greenhouse. Transplants were fertilized bi-weekly with a 20:20:20 fertilizer solution. After all danger of heavy frost had passed, the cabbage seedlings (3 weeks old) were transplanted in the field. Yield data were taken from the full length of the cabbage rows. Garlic cloves were planted 10cm apart in twin 8m long rows in late fall of 2006, just prior to the ground freezing. The garlic plot was mulched with approximately 30cm of straw just prior to ground freezing. The straw mulch was removed on May 1, Garlic bulbs were harvested in mid to late July as the tops died back. Spanish onions were seeded into Sunshine Mix #4 in 50 cell trays in the greenhouse on May 2. The transplants were fertilized bi-weekly with a 20:20:20 fertilizer solution. Seedling foliage was trimmed by 50% prior to transplanting. The four-week old seedlings were hand transplanted in 8m long twin rows after the risk of heavy frost had passed (June 1). Ornamental corn was hand seeded onto biodegradable IRT mulch in twin 6m long rows with 15 cm between plants in each row. The ornamental corn was drip irrigated. Data were taken from the full length of the ornamental corn rows. Heirloom tomatoes were seeded into Sunshine Mix #4 in the greenhouse in 50 cell trays. Transplants were fertilized bi-weekly with a 20:20:20 fertilizer solution. After all danger of heavy frost had passed, the tomato seedlings (5 weeks old) were transplanted in the field into IRT mulch. The heirloom tomatoes were staked in 2007 and the suckers were removed twice, beginning three weeks after transplanting. Yield data were taken from the centre plants of each tomato plot. Basil, mint, oregano, stevia and pennyroyal were seeded into Sunshine Mix #4 in 50 cell trays in the greenhouse on May 3. Transplants were fertilized bi-weekly with a 20:20:20 fertilizer solution. The herb seedlings were machine transplanted in 8m long twin rows, with 30 cm spacing between plants, on June 5 after all danger of frost had passed. Data were taken from a portion of each row, while the remainder of the row was used to evaluate bolting tolerance. Watermelon were seeded into Jiffy 7 peat pellets in the greenhouse on May 16. After all danger of frost had passed, transplants (three weeks old) were planted outdoors into IRT mulch. Plant rows (10 plants of each cultivar) were covered with perforated clear plastic supported by galvanized metal hoops spaced 1-1.5m within the row. The tunnels were removed on July 5 to ensure that the plants were adequately pollinated. Crop covers were placed on watermelon plants in early September for frost protection. Yield data were taken from the full length of the watermelon rows. Zucchini and specialty summer squash were direct seeded (50 cm apart) into black mulch on May 31 at a rate of two seeds per hole, and thinned to one plant/hole. Rows were 8 m long and 2

7 data were taken from the entire row. No crop covers were used for zucchini and other summer squash. All transplants were watered in with a fertilizer solution of 10:52:10 mixed according to label directions. The watermelon, heirloom tomato, zucchini and ornamental corn crops were drip irrigated. All other crops were overhead irrigated. All data are for marketable product, based on local grading standards. Growing season The 2007 crop year was a somewhat erratic, but produced decent yields of most crops. Temperatures in May and June were near normal. July was exceptionally warm (3.6 C higher than long term average), leading to rapid development of the warm season crops, but negatively affecting yields and quality of some of the cooler season crops. August featured consistent moderate temperatures which were near ideal for most crops. Conditions in September of 2007 were quite favorable, with no killing frost until late September. This allowed for a smooth harvest of the late maturing crops. A heavy rainfall event on June 17/18 (10.2 cm) caused localized flooding; this did not cause long term damage for cultivar trials but negatively affected high tunnel and plastic mulch cultural trials. A second heavy rainfall on August 19 (9.8 cm) also caused localized flooding around the high tunnel and plastic mulch trials, negatively affecting quality of maturing fruit. The moisture also resulted in a severe weed flush in some crops, however this competition likely occurred too late in the season to impact yields. Weather data May June July Aug. Sept. Season cumulative Growing degree days (base 5 C) Saskatoon Long-term average Mean temperature ( C) Saskatoon Long-term average Frost free season Saskatoon 2007 May 10 to September 14 = 127 days Long-term average 117 days 3

8 Insects and disease Root maggots were a significant problem in the Cruciferous crops (cabbage and turnips) in 2007, despite the application of insecticide at planting. Root maggots severely reduced the stand in both the direct seeded and transplanted cabbage. Root maggot populations were so intense in the turnip trial almost 100% of harvested roots were rendered unmarketable. However, late season invasion of the heads of cabbage by the maggots was relatively rare in Cabbage loopers were not abundant in 2007 and were easily controlled with a limited number of spray applications. Aster yellows are always present in SK, but levels in 2007 were unprecedented. Infected plants were detected in zucchini, tomato and watermelon trials but losses were minimal. Infection levels exceeded 50% for most cultivars in the carrot trial, resulting in a correspondingly high yield loss. It was interesting to note that the disease had already reached its maximum severity by the first carrot harvest on August 1. There were some substantial differences between the carrot cultivars in terms of the relative amounts of aster yellows infection, but losses in all cultivars were far in excess of grower tolerance. Heirloom tomato cultivars were pruned and staked, but their vigorous growth habit still limited air movement within the dense canopy of some cultivars. This led to gray mold and sclerotinia problems on fruit deep in the canopy. Tomato fruit growing on the outer, more exposed areas of the tomato plant had few disease problems. Sclerotinia was also significant for the small-leaved, globe forming ornamental basil, resulting in stand reductions. Powdery mildew was observed in the zucchini and summer squash trial; infection was cultivar dependent, but yields seemed unaffected by this disease due to vigorous growth habits of most cultivars. Yield and quality Overall favorable conditions in 2007 resulted in above average yields and quality for most crops tested. High maggot populations resulted in poor stands of red cabbage, reducing yields and making it difficult to compare the 2007 trial with previous trials. Turnip quality in 2007 was similar to the 2006 trials; nearly all roots were severely damaged by root maggots, and many roots rotted as the wounds caused by the maggots were invaded by decay organisms.. Extreme high temperatures in July accelerated die down of some garlic lines and may have caused the lower average bulb weight seen in 2007 compared with the 2006 harvest. Garlic grown during the 2006 growing season was held at 0 C and 60% RH from October, 2006 to May, Storage quality was variable. High weight loss (dehydration) and sprouting was observed in stiffneck cultivars; no stiffneck cultivars were recommended for long term storage. Softneck cultivars exhibited less weight loss and sprouting. Four of the nine softeck cultivars grown were recommended for storage. 4

9 Despite modifications to the production practices used in the heirloom tomato trial (pruning and staking), yields of mature, marketable fruit were once again limited. The plants grew very vigorously, with few fruit set early enough to reach maturity prior to fall frost. High fertility levels in the test plot area may be causing plants to stay vegetative, delaying fruit set. Heirloom tomatoes with small to medium sized fruit appear better suited for field production than largefruited cultivars. Ornamental corn yields and quality were excellent for some of the early maturing cultivars. Of the thirty-three cultivars tested, most produced marketable cobs. Cobs from the recommended cultivars dried well and provided excellent display material. Sweet corn yields were slightly above the 2006 average, but quality and taste were equivalent. This may reflect improvements in the cultivars being tested as well as favorable growing conditions in All corn cultivars tested reached 50% maturity in 2007 and 90% of the cultivars were completely harvested prior to the first killing frost. Watermelon yields were excellent and many cultivars were over 80% mature by the first killing frost. Determining fruit maturity in watermelon remains a challenge: some cultivars appeared mature but their flesh colour and taste indicated this was not the case. Similarly, some cultivars that appeared immature based on exterior characteristics were over-mature. Evaluating maturity is difficult for cultivar trials, but growing a limited selection would simplify the process for growers. Many high yielding cultivars with exceptional taste were identified. Bunching onion yields and quality were excellent. Onions were left in the field longer than average to determine resistance to bolting and bulbing. The 2007 Spanish onion trials were very successful, with all lines tested producing excellent yields of high quality bulbs. However, for most of the lines tested, a high proportion of the bulbs had multiple centers, a trait considered undesirable in the onion ring trade. Multiple centers is a cultivar characteristic, however, the incidence of this problem can be exacerbated by stresses such low or high temperature or drought. Skin set and quality were good, although all cultivars needed to be dried prior to storage. Yellow onions grown during the 2006 growing season were held at 0 C and 60% RH from October, 2006 to May, Storage quality of these onions was exceptional. There was only limited mold growth after four months of storage and losses to decay or dehydration were still limited after 8 months. Sprouting was also minimal in most lines. Of the forty-four cultivars evaluated, fifteen were recommended as excellent storage cultivars. Three plantings of leaf lettuce were tested in Stand establishment was poor in the spring planting and no yield data were taken. However, the cultivars were evaluated for taste, and some of the lines had excellent flavor. By contrast, the mid summer and fall plantings grew very well, producing a full stand of healthy plants. However, the quality and flavor of the both of these crops was poor quite by comparison with the early planting. This may reflect the sensitivity of leaf lettuce to heat. 5

10 Quality in the Nantes carrot trial was compromised by high levels of infection with the aster yellows pathogen. Although we attempted to grade out all roots with obvious infection, we suspect that some roots included in the quality assessments were actually infected - this may have lowered ratings for flavor and sweetness. In the later harvests a good portion of the carrots had become excessively large and woody. Of the thirty-two cultivars tested, only two were recommended for their yields and quality at all three harvest dates. Yields and quality in the green bean trial were generally excellent. Little or no disease was observed, and many cultivars yielded for four weeks or longer. Cultivars that received low ratings were generally more difficult and time consuming to harvest. Lodging, dense canopies, and/or pods held low in the canopy contributed to difficult harvests. Zucchini and specialty summer squash grew well in Fruit were harvested biweekly, and all cultivars produced consistent yields for eight weeks or longer. A heavy fertilizer application in late July kept the crop producing vigorously until frost. Because yields of most cultivars were excellent, fruit quality was particularly important in assigning ratings. The specialty summer squash cultivars were Mediterranean-type (light green, tear-shaped) unless specified. Several herb crops were evaluated in the 2007 growing season. Basil, oregano, cilantro, mint, and one cultivar each of stevia and pennyroyal were tested. All crops except cilantro were harvested several times by cutting all growth at 5cm above the ground and allowing the plant to regrow. Cilantro responded to this method of harvesting by immediately bolting. Cilantro was seeded sequentially throughout the season, and harvested by cutting the entire plant at ground level. Basil quality was variable depending on cultivar, but generally quality declined with each successive harvest because of the tendency to bolt. Basil cultivars were also evaluated for their potential as ornamental landscape plants. Similarly, oregano quality declined during the season. Mint, stevia, and pennyroyal quality remained through the season. 6