Abstract
Doublefile viburnum, the common name of Viburnum plicatum Thunb. f. tomentosum (Thunb.) Rend., is derived from the unique arrangement of the parallel, flat-topped inflorescences along the length of the horizontal branches. A plant in flower rivals that of flowering dogwood, Cornus florida L. Heretofore, chance seedlings have been selected and designated as cultivars, the most commonly cultivated being ‘Mariesii’, ‘Lanarth’, ‘Rowallane’, and ‘Roseum’. ‘Shasta’, a new cultivar introduction, is the first V. plicatum f. tomentosum cultivar to result from a breeding program, and the twelfth Viburnum introduction by the U. S. National Arboretum (1, 2, 3).
1 Research Entomologist. 2 Research Plant Pathologist. 3 Research Geneticist. 4 Research Horticulturist. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore
Abstract
A pilot study, of eight weeks duration, investigated the effects of flowering plants upon the behavior of hospitalized psychiatric patients. The introduction of flowering plants in the dining room setting was followed by a significant increase in vocalization, time spent in the dining room, and amount of food consumed. A transient, though not statistically significant increase in the number of social gazes occured during the first week the flowers were present.
Tobira Pittosporum (Pittosporum tobira) is an evergreen and broadleaf shrub with fragrant flowers. The introduction began in 1978. The plants blossomed and bore fruits in 1981. The seedlings grew up from seeding in 1982, then the freeze resistances of seedling were experimented with the Spartan Training System according to follow proper sequence and make steading progress rule. Some excellent plants were sifted out progressively. In order to enrich the afforestation materials in Jinan, it offers a new species.
Abstract
Fifty plant introduction lines of pepper were screened for resistance to curly top virus using the vector Circulifer tenellus Baker and a strain of virus known to be pathogenic on peppers Inoculations were done by caging either 3 or 15 viruliferous leafhoppers onto a leaf at the 4-true-leaf stage of growth. Four lines (PI 257053, PI 281297, PI 288938, and PI 357522) showed apparent resistance when inoculated by 3 leafhoppers, but non appeared resistant for more than a few days when inoculated by 15 leafhoppers. No correlation was found between leafhopper longevity on a plant and that plant’s resistance to the virus.
Field evaluations for resistance against downy mildew, incited by Pseudoperonospora cubensis (Berk. & M.A. Curtis) Rostovzev were conducted on 1076 U.S. Plant Introductions (PI) of Cucumis melo L. (melon). A disease index (DI) was calculated for each entry that had one or more resistant plants. Based on DI, PIs 271329 and 401644 were the most resistant overall (DI = 2.6 and 2.8, respectively). However, resistant plants exhibiting reaction type (RT) 3 were identified in 68 accessions, and 110 accessions had moderately resistant (RT 2) plants.
1 Research Plant Pathologist. 2 Horticulturist. Mention of a trade name or a proprietary product does not constitute a guarantee or warranty of the product by the U.S. Dept. of Agriculture, and does not imply approval of it to the exclusion
Abstract
Strategies for reducing bacterially induced frost damage to tender plants were examined. Introduction of the competitive bacterium, Erwinia herbicola M232A (not active in ice nucleation) did not lower the temperature at which freeze injury of tomato shoots occurred. Streptomycin was effective in reducing freeze damage of tomato shoots only when mixed with the Pseudomonas syringae suspension prior to plant inoculation. Spectinomycin, another aminoglycoside, was effective in reducing frost damage to tomato plants due to P. syringae. Bacteria present intercellularly (within the plant) may play a significant role in bacterial ice nucleation.
Abstract
A procedure using nutrient culture media was developed to screen bean seedlings on an individual plant basis for reaction to Fusarium solani (Mart.) Appel & Wr. f. sp. phaseoli (Burk.) Snyd. & Hans. From over 800 accessions, 18 plant introductions and several cultivars of Phaseolus vulgaris were found to be either resistant or tolerant. Susceptible plants, grown with ammonium nitrate as the nitrogen source (210 ppm N) showed reduced symptoms compared to plants grown on nitrate-N only. Ammonium as the sole nitrogen source was toxic to bean seedlings at identical nitrogen concentrations. Results based on the nutrient culture technique were generally consistent with field reactions.
Abstract
Inheritance of resistance to Colletotrichum lagenarium (Pass.) Ell. & Halst. race 2 in watermelon (Citrullus lanatus (Thunb.) Matsum & Nakai) was determined in progeny from crosses between resistant plant introductions (PIs) 189225, 271778, and 326515 and susceptible cultivars ‘Charleston Gray’, ‘Jubilee’, ‘Crimson Sweet’ and AWB-10 advanced line. Parents and progenies were screened for resistance in field and greenhouse plantings. Resistance of F1 plants indicated resistance was dominant. The F2 plants segregated 3 resistant: 1 susceptible. The backcross of the F1 to the susceptible parent segregated 1:1. Resistance in all Pis tested was controlled by a single dominate gene pair.