Gordon Johnson, Extension Vegetable & Fruit Specialist;gcjohn@udel.edu
Seed companies and propagators offer new vegetable varieties each year and favorite varieties are sometimes discontinued to the “chagrin” of growers. Some varieties retain favor for many years, whereas others might be used only a few seasons if some special situation, such as plant disease or marketing change, develops. Companies seek to place varieties in the marketplace that will have good adaptation to major growing areas and significant sales potential. Decisions to discontinue a variety are made due to lack of sales, difficulty of producing the seeds, narrow adaptation, pest susceptibility, introduction of improved varieties (higher yielding, better quality, wider adaptation, better disease packages, with added traits, or other improvement) or other market factors.
The ultimate value of a variety is determined by the grower (or processor in the case of processing vegetables): performance under his or her management, adaptation to environmental conditions specific to the area or farm, and having desired horticultural and market characteristics.
The following are some selection criteria for varieties taken from the Commercial Vegetable Production Recommendations extension publication for our Mid-Atlantic states (DE, MD, NJ, PA, WV, VA) online at http://extension.udel.edu/ag/vegetable-fruit-resources/commercial-vegetable-production-recommendations/.
Yield – The variety should have the potential to produce crops at the same or better yield and quality to those already grown. Is should be noted that harvested yield may be much less than potential yield depending on markets and quality factors.
Days to Harvest/Maturity – Choose varieties that meet grower or processor requirements based on days to harvest. Earliness is a major selection factor for first spring plantings and days to harvest is a critical selection factor for late summer and fall maturing crops, especially in shorter season areas of the region. Days to harvest in seed guides are based on the most common planting date and may be considerably longer in cooler periods or shorter in warmer periods. A more accurate guide to maturity will be Growing Degree Days which are calculated for a specific crop using daily highs and lows and a base temperature.
Disease and Insect Resistance – The most economical and effective means of pest management is through the use of varieties that are resistant or tolerant to diseases including those caused by fungi, bacteria, viruses, or nematodes. When all other factors are equal, select a variety with needed disease resistance or tolerance. In some vegetables, such as sweet corn, insect resistant varieties are also available and should be considered where they fit grower requirements.
Resistance to Adverse Environmental Conditions – Choose varieties that are resistant to environmental conditions that are likely to be encountered. This includes heat or cold tolerance; low levels of heat induced defects such a tuber heat necrosis in potato; drought tolerance; resistance to cracking, edema, and other wet weather disorders; low occurrence of nutrient disorders such as blossom end rot, leaf tip burn, or hollow stem; and low occurrence of hollow heart in watermelon.
Adaptability – Successful varieties must perform well under the range of environmental conditions and production practices usually encountered on the individual farm. Seasonal adaptation is another selection consideration (Spring vs Fall; early, main season, late).
Horticultural Quality – Choose varieties that meet grower or processor quality requirements. Quality attributes such as taste, texture, size, shape, color, uniformity, and amount of defects will often dictate variety selection. Grades, percentage by grade, or pack-outs are key quality attributes for some markets or processors. Variety test data such as soluble solids (sugars or sweetness), acidity, pungency, fiber content and consumer taste panel information can assist in variety selection where available. Processing performance is of major concern for frozen, canned or pickled vegetables. Other considerations include the ability to handle mechanical harvest or the ability to be packed and shipped distances with minimum damage in contrast to vegetables that are adapted only to hand harvest and local sales or short distance shipping. Other quality characteristics to consider include holding or storage ability, ripening characteristics, nutritional content, and culinary qualities.
Plant Characteristics – Plant characteristics that may be considered in variety selection include plant form such as bush, upright, or vining; plant height; plant size; location of harvested part on the plant; and ease of harvest.
Market Acceptability – The harvested plant product must have characteristics desired by both the grower and the buyer. Consider the requirements or desires of the consumer, packer, shipper, wholesaler, retailer, or processor. Included among these qualities are flavor, pack out, size, shape, color, culinary qualities, nutritional quality or processing quality. Specialty markets such as ethnic buyers, restaurants, or gourmet sales will have very specific variety requirements. Many vegetable seed companies offer varieties that are “transgenic” or “GMO” (genetically modified organism). GMO products in the food chain can be controversial, and some efforts are ongoing to regulate and label them at the state level. The grower is urged to be aware of current actions regarding GMO vegetables and potential effects on marketing.
There are many sources of information for growers to aid in choosing a variety. University trials offer unbiased comparisons of varieties from multiple sources. Commercial trials from seed distributors also offer multiple source comparisons. Seed company test results offer information about that company’s varieties. Look for results from replicated trials and multiple sites if available. Trials conducted in similar soils and growing environments and local trials are the most reliable indicators of what will have potential to perform well on a grower’s farm. Visits to local trials can provide good visual information for making decisions. Where quality is a prime concern, look for trials with quality data. Small trial plantings for 2 to 3 years are suggested for any variety or strain not previously grown. For a true comparison, always include a standard variety, one with proven consistent performance in the same field or planting.
We revised our format for variety recommendations for several vegetables in the Commercial Vegetable Production Recommendations. An example for snap beans follows. They are in table form with use, maturity, quality and pest reaction information.
