The world market for citrus (Citrus spp.) products has undergone dramatic shifts over the last decade. These shifts are influencing development and planting of new citrus cultivars. Seedlessness and very easy peeling have become paramount in mandarin types (C. reticulata and hybrids), and new cultivars are being developed through plant breeding and selection of new sports. In both sweet orange (C. sinensis) and grapefruit (C. paradisi), essentially all important cultivars are derived from a single original hybrid of each fruit type, and plant improvement has focused on selection of sports with redder color and extended maturity. The existence of many active citrus breeding programs makes it likely that we will continue to see evolution of new citrus cultivars over the foreseeable future.
Ed Stover, William Castle, and Chih-Cheng T. Chao
James N. Moore
Expansion of blueberry culture in North America has occurred during the past decade and is projected to continue into the next century. Thirty-six U.S. states and six Canadian provinces report some blueberry production. The area planted to blueberries has inreased by 19% in 10 years, with the largest increase (47%) in cultivated types and only 11% in wild blueberries. It is projected that the total area will increase by an additional 14% by the year 2000. New cultivars are proving of value and are affecting the composition of plantings. Greater interest is being given to mechanical harvesting, and new cultural and pest control innovations are being employed to enhance the economics of production. The expansion of blueberry production is being undergirded by expanded programs in problem-solving research.
James N. Moore
The blueberry cultivar situation in North America is undergoing rapid change. Attempts to grow blueberries in non-traditional areas, and increased biotic and abiotic challenges in traditional production areas, are fueling the search for superior, adapted cultivars. This survey of all blueberry-producing states/provinces in the United States and Canada provides the current status and projected trends in blueberry cultivar use in North America. Most (86%) of current hectarage is comprised of 25 northern highbush, 10 rabbiteye, and two southern highbush cultivars. `Bluecrop' is the dominant northern highbush cultivar, with 35% of the highbush area, while `Tifblue' occupies 40% of the rabbiteye area. Some historically important cultivars, such as `Jersey', `Weymouth', and `Woodard' are in decline. New cultivars of all blueberry types are beginning to have a positive impact on the blueberry industry.
Kevin M. Crosby, Daniel I. Leskovar, and Kil Sun Yoo
At the Vegetable and Fruit Improvement Center, plant breeding has produced pepper lines with enhanced beneficial phytochemical levels. TAM `Dulcito' is a new jalapeño cultivar with no detectable levels of capsaicin, but increased levels of lutein. In greenhouse cultivation, it contained 122 ppm of this important human health-related compound, which aids in prevention of macular degeneration. This is a significant improvement over popular cultivars, such as `Grande', which contained 25 ppm or less. In addition to improved lutein levels, `Dulcito' also possesses resistance to three important potyviruses: TEV, PepMoV, and PVY. In field trials at Weslaco, Texas, `Dulcito' outyielded both TAM `Mild Jalapeño 2', and `Mitla'. This new cultivar produces a concentrated set of large, thick-fleshed fruit with few cuticular cracks. Because of its lack of pungency, it should be useful for the processing industry. TAM `Tropic Bell' is a medium-sized, blocky bell with enhanced levels of both ascorbic acid and lutein compared to other cultivars. Grown under greenhouse conditions, it contained 100 ppm lutein compared to 6 ppm in `Jupiter'. It also contained 660 ppm ascorbic acid at the green stage, compared to less than 100 ppm for three commercial bell cultivars tested. `Tropic Bell' produced yields equal to both `Valiant' and `Summer Sweet' commercial hybrids at Weslaco. Fruit of `Tropic Bell' were slightly smaller than the hybrid cultivars. TAM `Tropic Bell' possesses resistance to the same three potyviruses as `Dulcito' and demonstrated excellent tolerance to Phytophthora capsici in a controlled inoculation. These two new cultivars will be useful for production in locations with high potyvirus pressure or as specialty market items for health-conscious consumers.
Robert R. Shortell, William A. Meyer, and Stacy A. Bonos
The apomictic breeding behavior of Kentucky bluegrass (Poa pratensis L.) results in many unique cultivars. A classification system was previously developed to characterize the large number of Kentucky bluegrass cultivars into different types. However, many new cultivars have been released since the last refinement of the classification system. The objectives of this study were to determine differences in morphological and agronomic characteristics among select Kentucky bluegrass cultivars representing the major classification types and to determine broad-sense heritability estimates for important morphological (plant height, panicle length, flag leaf height, and flag leaf length and width) and agronomic (rhizome spread) traits in Kentucky bluegrass. A spaced-plant nursery trial was established in the spring of 2003 at Adelphia, NJ. One hundred seventy-three cultivars and selections were planted in a randomized complete block design with three replications. The morphological and agronomic traits listed were measured on spaced plants. High Density type cultivars (formerly the Aggressive type cultivars) had the most prostrate growth habit with plant heights of 33 and 43 cm in 2004 and 2005, respectively. Mid-Atlantic and Texas × Kentucky bluegrass hybrids had the widest rhizome spread (Mid-Atlantic = 73 and 121 cm; Texas × Kentucky bluegrass hybrids = 72 and 122 cm) in 2004 and 2005, respectively. Broad-sense heritability estimates were high for plant height (H = 0.84), panicle length (H = 0.88), flag leaf height (H = 0.85), and rhizome spread (H = 0.85); moderate for flag leaf length (H = 0.71); and low for flag leaf width (H = 0.11). This study characterizes new cultivars into respective groups and identifies the genetic inheritance of important morphological and agronomic traits in Kentucky bluegrass.
Feng-yang Yu, Yue-e Xiao, Lin Cheng, Shu-cheng Feng, and Lei-lei Zhang
( Goldblatt and Manning, 2008 ). There are ≈70,000 known Iris cultivars, and more than 1000 new cultivars are produced by selection and hybridization every year ( Hu and Xiao, 2012 ). Few of those cultivars bloom in early spring (late March to mid-April in
James A. Schrader, Diana R. Cochran, Paul A. Domoto, and Gail R. Nonnecke
Increasing interest in grape (Vitis sp.) and wine production in the upper midwest region of the United States has created a need for science-based information that characterizes the potential of cold-climate cultivars to produce quality grapes with acceptable yields. We evaluated the yield and quality (composition) of grapes from 12 cold-climate, interspecific-hybrid grape cultivars (northern hybrids) grown in a randomized and replicated field plot in central Iowa. The grape trial was planted in 2008, and crop performance of cultivars was evaluated from 2012 through 2017 (yield) and 2014 through 2017 (berry composition). The trial included two established cultivars, five newer cultivars, and five advanced selections. The established cultivars included in the study as controls were Frontenac and St. Croix. The newer cultivars evaluated in this study were Arandell, Corot Noir, La Crescent, Marquette, and Petit Ami, and the advanced selections were MN 1189, MN 1200, MN 1220, MN 1235, and MN 1258. Yield and productivity were characterized by measuring yield per vine, number of clusters per vine, average cluster weight, and pruning weight. The fruit composition indices were soluble solids concentration (SSC), pH, titratable acidity (TA), and sugar:acid ratio (SSC ÷ TA). On the basis of their strong results for both yield and fruit composition measures, ‘Marquette’, MN 1235, and MN 1220 ranked as the top-performing cultivars in Iowa’s climate, followed by Petit Ami and St. Croix. ‘Petit Ami’ had slightly lower yield consistency and slightly lower results for SSC than did the top performing cultivars, and St. Croix had among the highest and most consistent yields of the trial but showed lower results for SSC and sugar:acid ratio than many of the other cultivars. ‘La Crescent’ had midrange yields and high SSC, but the high TA of ‘La Crescent’ fruit resulted in a low sugar:acid ratio at harvest. Two cultivars (MN 1258 and MN 1200) had relatively low yields in Iowa’s climate but achieved good results for composition indices. ‘Frontenac’ had high, consistent yields and achieved high SSC, but the very high TA of ‘Frontenac’ fruit resulted in a very low sugar:acid ratio compared with most other cultivars. The remaining three cultivars (Corot Noir, MN 1189, and Arandell) performed poorly in Iowa’s climate, showing both low yield and undesirable fruit composition indices compared with the other cultivars in the trial. An itemized summary of the relative ratings for yield and fruit composition is provided to aid growers in selection and management of grape cultivars for use in Iowa and other areas of similar climate.
Craig A. Ledbetter
‘Goshen Gold’ is the most recent apricot ( Prunus armeniaca L.) developed by the Agricultural Research Service Prunus breeding program in Parlier, CA. The new cultivar is self-compatible and capable of setting full crops without the presence of
R. L. Fery and P. D. Dukes
The Agricultural Research Service of the United States Department of Agriculture announced the release of Carolina Crowder southernpea on 12 October 1990. The new cultivar is well adapted for production throughout the southern U.S., where it can be expected to produce excellent yields of high quality, crowder-type peas. Carolina Crowder is resistant to the cowpea curculio, the major insect pest of the southernpea in southeastern production areas; blackeye cowpea mosaic virus, an important virus pathogen of southernpea in the United States; and root-knot, a severe root disease incited by several species of the root-knot nematode. Canned samples of fresh Carolina Crowder peas scored well in three years of quality evaluation tests. Pod color is a brilliant red at early green-shell maturity and a brilliant red heavily shaded with cranberry colored pigment at optimum green-shell maturity. The attractive pod color should make Carolina Crowder an excellent candidate for fresh market use. Carolina Crowder plants have a greater tendency to produce a second crop than plants of most southernpea cultivars.
David A. Evans
For many branded food products, the raw material is purchased as a commodity. Food companies provide added-value based on processing technology or marketing. The tools of plant biotechnology, which shorten the time for crop improvement and permit development of novel germplasm, offer the food industry the opportunity to modify raw materials and develop proprietary branded products. Such modifications will permit development of plant cultivars specifically selected for traits with added-value for the processor or the consumer. Biotechnology-developed cultivars offer the opportunity to develop produce that can be branded. The cell genetics tools of clonal propagation, somaclonal variation, gametoclonal variation, and protoplast fusion permit new cultivar development in an intermediate time scale, making them attractive for market introduction of proprietary products. When integrated with conventional breeding, these intermediate-term technologies will permit modification of fruits and vegetables over the course of the next several years. The longer-term technologies of plant genetic engineering will continue to have an impact on manipulation of specific traits, resulting in second-generation products specifically designed for consumers.