Nineteen cultivars of muscadine grape (Vitis rotundifoli a Michx.) were divided into three classes based on the mean number of shoots developed during micropropagation. The cultivars in each class were then compared for pedigree similarities and common ancestors were identified. It was determined that the difficult to propagate class always had close direct lineage to either `White Male' or `Scuppernong', both selections from the wild. The intermediate class tended to be composed of newer cultivars which were more distantly related to `White Male' and `Scuppernong'. The easy to propagate class had diverse family histories and none of them included either `White Male' or `Scuppernong' for three or more generations. It is hypothesized that some factor, yet undetermined, has an influence on the ability of muscadine grape to be micropropagated.
R. P. Lane and C. D. Robacker
Andrew R. Jamieson and Katherine Sanford
Twelve clones of `Blomidon' strawberry (Fragaria xananassa) exhibiting a range of severity of June Yellows symptoms were grown in field plots to measure effects on productivity. Field plot layout was a randomized block design with four blocks. Plots were matted rows developed from five plants spaced at 45 cm inrow. Fruit samples were frozen and later analyzed for soluble solids concentration, total acidity, and pH. In the greenhouse, self-pollinated seedlings grown from these clones were rated for symptom expression as an additional measure of severity of June Yellows. Large differences in marketable yields were recorded, ranging from 1.94 t·ha–1 to 14.67 t·ha–1. Clones with severe symptoms produced smaller fruit. Small clonal differences were measured in total acidity and pH. A strong correlation was observed between the percentage of symptomless seedlings and the yield of the parental clone. This may lead to a test to predict whether a new cultivar will succumb to June Yellows.
Henry M. Donselman
Tissue culture labs based in countries with high labor costs are becoming more dependent on proprietary plants. This has increased the necessity of high profile plant breeding programs. Foliage and flowering plant breeding programs have evolved rapidly to take advantage of the benefits associated with tissue culture labs.
Breeding strategies and methods will be discussed on existing flowering and foliage programs for Anthuriums, Euphorbia, Aloe, Spathiphyllum, Homalomena, and Dieffenbachia. Embryo rescue in the lab has increased the survival of wide crosses from different species within a genera. Rapid multiplication of selected clones has increased the efficiency of screening for disease and insect resistance in the selection of new cultivars. Marketing, along with improved horticultural characteristics, determine the success of new releases.
F. Kappel, P. Toivonen, D.-L. McKenzie, and S. Stan
Several sweet cherry (Prunus avium L.) cultivars were stored in air or modified-atmosphere packages (MAP) at 1 °C for 2 or 4 weeks, respectively. The new cultivars included `Santina', `Sumpaca Celeste', `Sumnue Cristalina', `Sumste Samba', `Sandra Rose', `Sumleta Sonata', and `Skeena', and the standards were `Lapins', `Sweetheart', and `Bing'. Fruit were rated for defects (stem browning, stem shrivel and fruit surface pitting), and fruit quality at harvest and after storage. Weight loss during storage was influenced by year, storage treatment, and cultivar. Stem shrivel, stem browning, and fruit surface pitting varied among cultivars and years. Generally, fruit stored in MAP had higher fruit firmness than at harvest or when stored in air. The respiration rate of fruit was lower in later than in earlier maturing cultivars, but respiration rate at harvest was not related to any of the quality measurements taken after storage.
James N. Moore
Blackberries have long been a popular fruit in the southern U.S., and they are widely grown there, with excellent potential for expanded production. Raspberries are also well-liked, but not widely grown, due to lack of adapted cultivars. Great progress has been made, particularly in the past four decades, in improving blackberry cultivars for the South, but little effort has been given to raspberry improvement. Germplasm exists within Rubus to provide great advances in conventional cultivar improvement in both subgenera and for creating new types of fruits through interspecific hybridization. Germplasm and breeding strategies will be discussed that would result in new cultivars to serve as the foundation on which to build much expanded blackberry and raspberry industries in the southern United States.
The Louisiana Agricultural Experiment Station has released a new pinkeye purple hull-type southernpea cultivar for the fresh market. The new cultivar, Quickpick, originated from a cross between breeding lines LA 88-74 and LA 88-9. `Quickpick' has a bush-type plant habit with synchronous pod set and is suitable for either machine- or hand-harvest. Pods of `Quickpick' are straight, ≈20 cm long, and about 8 mm in diameter. Fresh peas are green with a light-pink eye. Yield of `Quickpick' equaled or surpassed yield of `Texas Pinkeye Purple Hull' in machine-harvested replicated tests. In hand-harvested replicated tests, yield of `Quickpick' was comparable to `Texas Pinkeye Purple Hull', `Coronet', `Pinkeye Purple Hull-BVR', `Mississippi Pinkeye', and `Santee Early Pinkeye'. `Quickpick' is immune to a Georgia isolate of blackeye cowpea mosaic virus, a major virus of southernpea in the United States.
Margaret J. Makinde, Adenike O. Olufolahji, and Olanrewaju A. Denton
A total of 45 varieties of okra (Abelmoschus esculentus) were evaluated for earliness in fruiting and high fruit yield. In Nigeria selection in okra is for large, spiny fruit with high drawing ability. So far the variety (cultivar) NHAC 47-4 has been well-accepted by both the Nigerian farmers and consumers. It fruit within 42 days and draws and retains fresh color when boiled. These new cultivars, NHAC147 and NHAC 148, were found to fruit within 38 to 40 days and they are of comparable yield of up to 40 fruit per plants. They were found to be drought-tolerant and carry fruit of up to five of same age and size-high degree of uniformity. They are therefore being recommended because they have short stems and NHAC148 has fewer spines than NHAC47-4 AND NHAC 147.
Creighton L. Gupton and Barbara J. Smith
Eight cultivars, including five recent releases, five selections from the Florida AES, and 16 selections from the Georgia AES were planted in the muscadine germplasm working collection at McNeil, Miss., in 1992. All cultivars and one replication of the selections were evaluated in 1997. None of the new cultivars yielded as much as `Fry', the standard fresh fruit cultivar. The percent dry picking scar of `Dixie' and `Fry' was low. `Tara', `Polyanna', and `Fry' produced the largest berries. Percent soluble solids was lowest in `Fry', `Nesbitt', and `Alachua' but highest in `Dixie' berries. `Fry', `Alachua', and `Polyanna' had the lowest and the other cultivars did not differ in number of seed per berry. One selection, 33-1-4, appeared to have the qualities of a potential cultivar. Incidence and severity of berry rots were generally low.
Richard L. Fery
The USDA has released a new, pinkeye-type southernpea cultivar that is homozygous for the gc gene conditioning the green cotyledon trait. The new cultivar, `Charleston Greenpack', can be harvested at the near-dry stage of pod maturity without loss of the pea's fresh green color. `Charleston Greenpack' originated as a bulk of an F8 [`Kiawah' × (`Kiawah' × `Bettergreen')] population grown in 1994. Except for the green seed color, a tendency for a slightly greener foliage, and a slightly smaller pea size, the phenotype of `Charleston Greenpack' is quite similar to those of `Coronet' and `Pinkeye Purple Hull-BVR'. The results of replicated field tests indicate that `Charleston Greenpack' yields are comparable to those of `Coronet' and `Pinkeye Purple Hull-BVR'. Results of raw product evaluations conducted at a commercial freezing facility indicate that `Charleston Greenpack' produces an excellent processed product. `Charleston Greenpack' has excellent field resistance to blackeye cowpea mosaic virus, the major pathogen of southernpea in the United States.
Kimberly J Walters, George L. Hosfield, and James D. Kelly
Ninety-eight percent of the navy beans (Phaseolus vulgaris) grown in the US are processed. Thus, new cultivars considered for release must meet industry standards. Canning quality behaves as a classical QTL which precludes its selection and evaluation in early generations. Such delays add a measure of inefficiency to a breeding program. Indirect selection for canning quality using molecular markers could increase efficiency. RAPD markers are more useful than RFLP's, in Phaseolus, due to a simpler protocol and a higher level of polymorphism within genetically related cultivars. Three populations of RIL's, derived from crosses between cultivars with standard and sub-standard canning quality, were screened to identify markers associated with canning quality. Material for evaluation was grown at two locations, in three replications and processed, in the Food Science Processing Lab, following industry standards. Quality traits measured were: processed texture, color and appearance. Associations of putative markers with canning quality were identified using ANOVA and Mapmaker programs