CONTRAST PARANASAL SINUSOGRAPHY FOR EVALUATION OF DISEASE OF THE PARANASAL SINUSES OF FIVE HORSES

Positive-contrast paranasal sinusography was employed to evaluate 5 horses with disease of the paranasal sinuses. Diseases of the paranasal sinuses of these horses were progressive ethmoidal hematoma, bacterial sinusitis secondary to dental disease, and neoplasia. Positive-contrast sinusography allowed more complete evaluation of disease of the paranasal sinus of the horse than did survey radiographs.     

Classification of some indigenous maize collections from Southern and Southeastern Europe

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.     

Potato notes

American Journal of Potato Research -     

关于北美阔叶材行业优先研究项目的调查研究

美国林产品杂志58卷37期发表了David Brinberg等人的论文,报道了一项关于如何确定北美阔叶材行业优先研究项目的调查研究,论文指出了过去所用方法的缺点,报道了一种谋求改进的新方法。     

Development of the components of a cytoplasmic male sterility hybrid system in rye through anther culture

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.     

Developing Strategies for Spatially Variable Nitrogen Application in Cereals, Part I: Winter Barley

For precision agriculture to provide both economic and environmental benefits over conventional farm practice, management strategies must be developed to accommodate the spatial variability in crop performance that occurs within fields. Experiments were established in crops of winter barley (Hordeum vulgare L.) over three seasons. The aim of which was to evaluate a set of variable rate nitrogen strategies and examining the spatial variation in crop response to applied N. The optimum N application rate varied from 90 to in excess of 160 kg [N] ha⁻¹ in different parts of the field, which supports the case for applying spatially variable rates of N. This, however, is highly dependent on seasonal variations, e.g. the quantity and distribution of rainfall and the effect that this has on soil moisture deficits and crop growth. Estimates of yield potential, produced from either historic yield data or shoot density maps derived from airborne digital photographic images, were used to divide experimental strips into management zones. These zones were then managed according to two N application strategies. The results from the historic yield approach, based on 3 yr of yield data, were inconsistent, and it was concluded that that this approach, which is currently the most practical commercial system, does not provide a suitable basis for varying N rates. The shoot density approach, however, offered considerably greater potential as it takes account of variation in the current crop. Using this approach, it was found that applying additional N to areas with a low shoot population and reducing N to areas with a high shoot population resulted in an average strategy benefit of up to 0·36 t ha⁻¹ compared with standard farm practice.