The results of recently completed genetic studies indicate that the green cotyledon trait exhibited by the southernpea [Vigna unguiculata (L.) Walp.] cultivar Bettergreen is conditioned by a single recessive gene. This gene, designated green cotyledon and symbolized gc, is neither allelic to nor linked with the gt gene that conditions the green testa trait exhibited by the cultivar Freezegreen. The color of seeds harvested from plants homozygous for both the gc and gt genes is superior and more uniform than the color of seeds harvested from either Better-green or Freezegreen plants. This observation suggests that efforts should be initiated to study the feasibility of using both the gc and gt genes to develop cultivars that produce seed with an enhanced, persistent green color. The selection methodology for both seed traits is rapid and reliable. The green cotyledon trait can be selected in the seed stage.
R. L. Fery and P. D. Dukes
Melike Cirak and James R. Myers
quality standards are not as stringent, may have colored seeds. Another seedcoat color type being used in snap bean is persistent color ( pc ), with ≈40% of snap bean acreage in the United States planted to cultivars with this trait (Myers et al
R.L. Fery and J.A. Thies
The development of southernpea cultivars with a persistent green seed color has been the subject of much interest in the U.S. horticultural industry for more than two decades because seeds of such cultivars can be harvested at the dry seed stage of maturity without loss of their fresh green color. Two genes, gt (green testa) and gc (green cotyledon), are known that condition a persistent green seed color in southernpea. The gt gene was identified more than 25 years ago, but cultivars containing this gene have not been well-accepted by the industry because of the frequent occurrence of discolored (brown stains) seeds. Cultivars containing the more recently discovered gc gene, however, do not produce the discolored seeds and are used extensively in the frozen food industry. Efforts to develop cream-, blackeye-, and pinkeye-types of cultivars containing both the gt and gc genes are nearing completion. The dry seeds harvested from candidate cultivars homozygous for both the gt and gc genes are stain free and exhibit a deeper and more uniform green color than seeds harvested from cultivars homozygous for just one of the genes. It is anticipated that newer cultivars containing both of the genes that condition a persistent green seed color will not only have an enhanced value to the frozen food industry, but will also have great potential for use in the dry pack industry.
The development of southernpea (Vigna unguiculata) cultivars with a persistent green seed color has been the subject of much interest for more than two decades because seeds of such cultivars can potentially be harvested at the near-dry seed stage of maturity without loss of their fresh green color. The success of the cream-type cultivar Bettergreen, which is homozygous for the gc gene conditioning green cotyledons, demonstrated that the development of cultivars with persistent green seed color is feasible. In 1990, an effort was initiated to develop a pinkeye-type southern pea cultivar homozygous for the gc gene. The pinkeye is the major cultivar class of southernpea utilized for processing in the United States. Seeds containing embryos homozygous for the gc gene are easily identified, and this ability to select in the seed stage greatly facilitated the rapid development of advanced breeding lines. More than two dozen advanced generation pinkeye lines with green cotyledons were ready for preliminary field testing in 1995, and seven were selected for detailed evaluation in 1996. Results of the 1996 tests indicate that the gc gene has been successfully incorporated into elite pinkeye germplasm.
Richard L. Fery
The USDA–ARS has released a new pinkeye-type southernpea cultivar named GreenPack-DG. GreenPack-DG is the first pinkeye-type southernpea to be released that has a persistent green seed phenotype conditioned by both the green cotyledon gene (gc) and the green testa (gt) gene. The new cultivar was developed from a cross between Charleston Greenpack (green cotyledon phenotype) and the breeding line USVL 97-296 (green testa phenotype). Except for longer pods, GreenPack-DG is similar in appearance and maturity to Charleston Greenpack. Dry GreenPack-DG seeds have a richer and more-uniform green seed color than dry seeds of Charleston Greenpack. GreenPack-DG seeds are much less susceptible to color loss due to blanching when harvest is delayed than are seeds of green-cotyledon cultivars such as Charleston Greenpack. Color loss is a critical problem in production systems where preharvest desiccants are used to facilitate mechanical harvesting operations. The 7-day delay between application of the desiccant and initiation of harvesting operations can result in serious color degradation. Results of 3 years of replicated field tests at Charleston, S.C., indicate that GreenPack-DG yields are comparable to Charleston Greenpack yields. The new cultivar has excellent field resistance to blackeye cowpea mosaic virus and does not produce hard seeds. GreenPack-DG is recommended for trial by the frozen food industry as a replacement for Charleston Greenpack. Protection for GreenPack-DG is being sought under the Plant Variety Protection Act.
Richard L. Fery
The USDA has developed four pinkeye-type southernpea candidate cultivars (Experimental designations: US-1090, US-1092, US-1094, and US-1096) that have a persistent green seed phenotype conditioned by both the green cotyledon gene (gc) and the green testa (gt) gene. Each of the candidate cultivars produces dry seeds that have a richer and more uniform green color than seeds of either green cotyledon or green testa phenotype cultivars. Seeds of these candidate cultivars are much less susceptible to color loss due to blanching when harvest is delayed than are seeds of green cotyledon phenotype cultivars. Color loss is a critical problem in production systems where pre-harvest chemical desiccants are used to facilitate mechanical harvesting operations. The 7-day delay between application of the desiccant and initiation of harvesting operations can result in serious color degradation. The results of four 6-replicate field trials indicate that the yield potential of each of the four candidate cultivars is equal to that of the green cotyledon pinkeye-type cultivar Charleston Greenpack. Additionally, each of the candidate cultivars is resistant to blackeye cowpea mosaic virus and do not produce hard seeds that are troublesome to frozen food processors. The seed shape, seed size, and seed eye pattern traits of the candidate cultivars are similar to those of Charleston Greenpack.
Tara E. Paranick and N. Suzanne Lang
Shaded environments present major obstacles for establishing high quality, persistent, and resistant turfs. Exogenous fructose applications are being examined as a potential method to counteract the effects of shade on turf. This work examines the effectiveness of fructose applications under different light levels on two fine leaf fescue cultivars: chewings fescue (Festucarubra var. commutata) `SR5100' and creeping red fescue (Festucarubra var. rubra) `Dawson'. The experiment was conducted at Michigan State University, East Lansing, inside a simulated dome environment. The experiment was a randomized complete-block design that began 21 Oct. 2004 with two main factors: light and fructose. There were three light treatments: ambient light (shaded); supplemental high light; and supplemental low light. Fructose (0% or 1.25% weight/volume), dissolved in water with an organosilicone adjuvant, was applied once per week. Quality and color ratings, clippings, core samples, density, and leaf reflectance were recorded. In addition, light response curves (LRC) were taken inside an Econoair®
growth chamber using a LI-COR-6400® on the fine fescues, kentucky bluegrass (Poa pratensis) `Cynthia', and bermudagrass (Cyondon dactylon) `Princess'. Preliminary results show that fructose had no significant effect in each light treatment for turf quality and color. However, fructose had a significant impact on clipping weights and density. The LRC specified the required and potential carbon needs as well as indicated the threshold levels, respectively, by species. The impact of fructose alone and in combination with supplemental light on photosynthesis efficiency will be presented.
Charles E. Johnson, Ed O'Rourke, and James E. Boudreaux
. Plots were replicated three times with one tree per plot. Fruit were immediately taken to the laboratory for evaluation. Each replicate was weighed and divided into two lots for measuring soluble solids and color. Fruit from one lot of each cultivar were
Richard L. Fery
‘WhiteAcre-DG’ is a new southernpea [ Vigna unguiculata (L.) Walp.] cultivar released in 2008 by the Agricultural Research Service of the U.S. Department of Agriculture. The major attribute of the new cultivar is its persistent green seed
Charles E. Johnson, Ed O'Rourke, and James E. Boudreaux
the laboratory for evaluation. Each replicate was weighted and divided into two lots for measuring soluble solids and color. Fruit from one lot of each cultivar were peeled and macerated. Approximately 3 mL of pulp was used to determine percent soluble