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51.
Anther culture was applied as a method to develop the essential components of a cytoplasmic male sterility hybrid system in
rye (Secale cereale L.). These components are the male sterile seed parent (A line), its isogenic maintainer counterpart (B
line) and the restorer pollen parent (R line). Australian rye cultivars were crossed reciprocally to the cultivar ‘Luchs’
which carries the Pampa male sterile cytoplasm (cms-P). Anthers of the F1s in the cms-P cytoplasm (primary cross) and their
reciprocals in the normal cytoplasm (reciprocal cross) were cultured in a modified C17 medium. Male sterile and male fertile
doubled haploids were obtained from the anther culture of the F1s in the cms-P cytoplasm. Testcrosses indicated that the male
sterile doubled haploids were A lines and the male fertile doubled haploids were R lines (restorers). The anther culture of
genotypes in the normal cytoplasm (reciprocal cross) gave all male fertile doubled haploids. Testcrosses indicated that the
male fertile doubled haploids were R lines (restorers) in the normal cytoplasm. The expected maintainer B lines were not identified
because of the limited number of doubled haploids obtained from the anther culture of reciprocal crosses. Experimental single
cross hybrids between male sterile and restorer male fertile doubled haploids showed high levels of heterosis. The results
of this study have significant economic implications especially in the production of hybrids in several species.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
52.
Classification of some indigenous maize collections from Southern and Southeastern Europe 总被引:1,自引:0,他引:1
A race classification, based on multiple variate analysis using 23 morphological characteristics, was applied to 42 indigenous maize strains from Southeastern Europe, 20 race collections from Spain and 2 Corn Belt Dent hybrids from the United States. Based on the evidence obtained and on comparisons with other studies, the Southeastern European strains were assigned to one of seven races or race groups, of which at least five appear on historical evidence to be derived directly or by recent hybridization from importations originating in North America. In contrast, the majority of the Spanish collections appeared to have their origins in importations from Central America or the West Indies. Very little similarity was observed between the Spanish and Southeastern European collections, when considered overall.Detailed classification and study of European maize appears highly desirable as an aid to utilization of this potentially valuable germ plasm in world maize breeding programs. 相似文献
53.
A national and interregional programming model is analyzing the effects of banning Chlordane and Heptachlor from U.S. agriculture. The model has sectors for land and water resources, crop and livestock production, commodity transportation and domestic and foreign demand. The central Corn Belt would be put at some disadvantage and lose production to other regions. Soybeans and small grains would replace corn on low lands and the imputed values of this land would decline. Crop rotations would include somewhat less corn. 相似文献
54.
Fleshman MK Lester GE Riedl KM Kopec RE Narayanasamy S Curley RW Schwartz SJ Harrison EH 《Journal of agricultural and food chemistry》2011,59(9):4448-4454
Muskmelons, both cantaloupe (Cucumis melo Reticulatus Group) and orange-fleshed honeydew (C. melo Inodorus Group), a cross between orange-fleshed cantaloupe and green-fleshed honeydew, are excellent sources of β-carotene. Although β-carotene from melon is an important dietary antioxidant and precursor of vitamin A, its bioaccessibility/bioavailability is unknown. We compared β-carotene concentrations from previously frozen orange-fleshed honeydew and cantaloupe melons grown under the same glasshouse conditions, and from freshly harvested field-grown, orange-fleshed honeydew melon to determine β-carotene bioaccessibility/bioavailability, concentrations of novel β-apocarotenals, and chromoplast structure of orange-fleshed honeydew melon. β-Carotene and β-apocarotenal concentrations were determined by HPLC and/or HPLC-MS, β-carotene bioaccessibility/bioavailability was determined by in vitro digestion and Caco-2 cell uptake, and chromoplast structure was determined by electron microscopy. The average β-carotene concentrations (μg/g dry weight) for the orange-fleshed honeydew and cantaloupe were 242.8 and 176.3 respectively. The average dry weights per gram of wet weight of orange-fleshed honeydew and cantaloupe were 0.094 g and 0.071 g, respectively. The bioaccessibility of field-grown orange-fleshed honeydew melons was determined to be 3.2 ± 0.3%, bioavailability in Caco-2 cells was about 11%, and chromoplast structure from orange-fleshed honeydew melons was globular (as opposed to crystalline) in nature. We detected β-apo-8'-, β-apo-10', β-apo-12'-, and β-apo-14'-carotenals and β-apo-13-carotenone in orange-fleshed melons (at a level of 1-2% of total β-carotene). Orange-fleshed honeydew melon fruit had higher amounts of β-carotene than cantaloupe. The bioaccessibility/bioavailability of β-carotene from orange-fleshed melons was comparable to that from carrot (Daucus carota). 相似文献
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Paul M. Mehrle Mack T. Finley J.Larry Ludke Foster L. Mayer T.Earl Kaiser 《Pesticide biochemistry and physiology》1979,10(2):168-173
Black ducks, Anas rubripes, were exposed to dietary toxaphene concentrations of 0, 10, or 50 μg/g of food for 90 days prior to laying and through the reproductive season. Toxaphene did not affect reproduction or survival, but reduced growth and impaired backbone development in ducklings. Collagen, the organic matrix of bone, was decreased significantly in cervical vertebrae of ducklings fed 50 μg/g, and calcium conentrations increased in vertebrae of ducklings fed 10 or 50 μg/g. The effects of toxaphene were observed only in female ducklings. In contrast to effects on vertebrae, toxaphene exposure did not alter tibia development. Toxaphene residues in carcasses of these ducklings averaged slightly less than the dietary levels. 相似文献
58.
Deriving the quantity of items is an abstract form of categorization. To explore it, monkeys were trained to judge whether successive visual displays contained the same quantity of items. Many neurons in the lateral prefrontal cortex were tuned for quantity irrespective of the exact physical appearance of the displays. Their tuning curves formed overlapping filters, which may explain why behavioral discrimination improves with increasing numerical distance and why discrimination of two quantities with equal numerical distance worsens as their numerical size increases. A mechanism that extracts the quantity of visual field items could contribute to general numerical ability. 相似文献
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