observed for decades and was described as early as the 1930s ( Bliss, 1937 ). This phenomenon, previously described as “cross-cut” or “V-cut,” is expressed as cuts in the fruit stalk, which cause the drying and dropping of fruit bunches. These symptoms have
represent different regions of the image while the background remained the same: cut pericarp surface (the part of the cut pepper in the cross-section that is not damaged or healthy tissue); cut external surface (fruit skin shown on the pepper slice
cross between a pummelo ( C. grandis Osbeck) and a sweet orange [ Citrus sinensis (L.) Osbeck] ( Barrett and Rhodes, 1976 ; Gmitter, 1995 ; Scora, 1975 ; Scora et al., 1982 ). The increasing competition and popularity of grapefruit in international
productivity of progeny families across all crosses ranged from four to 14 cut flowers per plant per year. The cv within progeny families was 3-fold that of cv between families indicating that considerable variation was created through hybridization. This
in horizontal orientation at or near the base of the rotatable cross-arm also allows for easy rotation of the cross-arm which can be performed without causing extensive cane breakage when the RCA trellis and cane training system is used as part of
, 1917 ). Peonies are heritage perennial flowers that hold special cultural value in the United States. They are a traditional Memorial Day cut flower and have become a popular wedding flower (D. Hollingsworth, personal communication). These plants are
. Some of the research tools being used in this germplasm improvement program include embryo/ovule rescue from wide interspecific crosses, polyploid induction, and in vitro propagation. These studies depend on effective tissue culture protocols. There
Abstract
Hybrids from single and 3-way crosses involving gynoecious, hermaphroditic, monoecious, and androecious parent lines of cucumber (Cucumis sativus L.) were grown for 2 summers near East Lansing, Michigan. Frequencies of gynoecious hybrid plants varied significantly between years for most crosses. The femaleness (% gynoecious plants) of most single cross hybrids from gynoecious × androecious crosses was greater than ‘Pioneer’ for 1973 but not as clear-cut in 1974. The same differences were observed for 3-way crosses derived from gynoecious-hermaphroditic F1 seed parents crossed with an androecious pollen parent The differences were more marked for 1973 than 1974. However, when the femaleness of 3-way hybrids derived from the same F1 seed parents crossed with either androecious or monoecious pollen parents were compared, the androecious crosses were consistently more female. Overall, hybrids derived from androecious pollen parents were as highly female, or more so, than hybrids derived from monoecious pollen parents including hybrid ‘Pioneer’.
Efforts to improve postharvest longevity of fresh-cut flowers has only recently turned toward selection and breeding. Conventional methods to extend keeping longevity of cut flowers depend on use of chemical treatment placed in holding solutions. Postharvest longevity studies were initiated with Antirrhinum majus L. (snapdragon) to determine: if natural genetic variation existed for cut-flower longevity, the inheritance of the trait, heritability, and associated physiology. Evaluation of commercial inbreds held in deionized water revealed a range in cut-flower longevity from a couple of days to 2.5 weeks. The shortest- and longestlived inbreds were used as parents in crosses to study the aforementioned areas of interest. Information will be presented on inheritance of cut flower longevity based on populations evaluated from matings for generation means analysis and inbred backcross method. Also presented will be information on stomata, transpiration, carbohydrate, fresh-weight change, and forcing temperature relative to postharvest longevity.
A tissue culture protocol was developed that increased the germination percentage and decreased the lag time to germination for strawberry (Fragaria x ananassa Duch.) achenes. This technique involved cutting surface-sterilized achenes across the embryo axis then placing the shoot apex/radicle-containing sections on semisolid Murashige and Skoog medium lacking hormones. Cut achenes began germinating 5 days after culture and achieved maximum germination (97% to 100%) in less than 2 weeks, compared to whole achenes, which began to germinate 7 to 10 days after sowing and required more than 7 weeks for maximum germination (<50%). Enhanced germination of cut achenes was a general phenomenon since achenes from 231 hybrid crosses responded similarly. Following placement on culture medium, cut achenes could be stored up to 8 weeks at 4C then removed to 27C, where germination and seedling development occurred at percentages and rates comparable to freshly cut achenes. Achenes did not require stratification before cutting to exhibit increased germination. Nearly 100% of the achenes from freshly harvested red-ripe, pink and white strawberries germinated after cutting and culture, although cut achenes from white and pink berries germinated more slowly than those from red-ripe berries. Achenes from green berries, whether whole or cut, did not germinate. This method of “embryo rescue” could be used to generate more seedlings from poorly germinating hybrid crosses, would considerably decrease the time from sowing to seedling production compared to traditional means, and would produce seedlings of uniform age for subsequent field evaluation.