Genetic diversity of diploid Japanese strawberry species based on microsatellite markers     

Wambui Njuguna  Kim E. Hummer  Christopher M. Richards  Thomas M. Davis  Nahla V. Bassil 《Genetic Resources and Crop Evolution》2011,58(8):1187-1198

The United States Department of Agriculture (USDA)—Agricultural Research Service (ARS)—National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon, is a genebank that preserves strawberry genetic resources. Representatives of two Japanese diploid species, Fragaria iinumae Makino and F. nipponica Makino were collected for conservation by the NCGR during an expedition to Hokkaido, Japan. Fragaria iinumae may be a genome contributor to the cultivated octoploid strawberries. The objective of this study was to evaluate the genetic diversity of these two species by using simple sequence repeat (SSR) markers. Twenty of 82 Fragaria-derived SSRs, polymorphic among and within the two species, were selected for genetic analysis of 137 accessions. Genetic diversity, based on the proportion of shared alleles between the two species, in F. nipponica (0.4542) and F. iinumae (0.1808) was significantly different. Three wild interspecific hybrids were identified from intermediate memberships in the two diploid species groups revealed by using the clustering program, Structure. Principal coordinate analysis followed by non-parametric modal clustering (PCO-MC) grouped accessions into two clusters representing the two diploid species. Further clustering within the species groups generated with the program, STRUCTURAMA^TM, resulted in seven subclusters in F. iinumae and three in F. nipponica, which may represent breeding populations appropriate for clonal conservation. Long-term preservation of the species populations and the limited number of hybrids on the island is discussed relative to their geographical distribution and the geological history of Hokkaido Island.  相似文献   

Report of potato nutrition (fertilization) committee     

Arthur Hawkins  O. A. Lorenz  N. R. Richards  L. M. Ware  G. V. C. Houghland 《American Journal of Potato Research》1959,36(2):73-75

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Analysis of genetic diversity in a collection of Plantago species: application of ISSR markers     

Bagheri  Motahareh  Heidari  Bahram  Dadkhodaie  Ali  Heidari  Zahra  Daneshnia  Negar  Richards  Christopher M. 《Journal of Crop Science and Biotechnology》2022,25(1):1-8

Journal of Crop Science and Biotechnology - The analysis of genetic diversity in medicinal plant species can greatly facilitate germplasm conservation and selection for use in breeding schemes. The...  相似文献   

Integrating new soybean varieties for soil fertility management in smallholder systems through participatory research: Lessons from western Kenya     

M. Misiko  P. Tittonell  J.J. Ramisch  P. Richards  K.E. Giller 《Agricultural Systems》2008,97(1-2):1-12

The aim of this paper was to understand the process of selecting soybean (Glycine max [L.] Merr.) promiscuous varieties by smallholders for soil fertility management in western Kenya. Eight varieties were screened on 2.5 m × 3 m plots that were managed according to farmers’ practices and evaluated through participatory monitoring and evaluation approaches. Farmers selected preferred varieties and explained their reasons (criteria) for making the selections. Seven promiscuous varieties had better yields than a local one. Farmers’ selection criteria fell into three broad categories relating to yield, appearance and labour. Selection criteria were not primarily aimed to improve soil fertility. This created a challenge to embed the new varieties within the local farming systems for soil fertility improvement. This study shows that farmer criteria for selecting varieties overlapped with scientific procedures. We propose co-research activities targeted to strengthen farmer experimentation skills, their understanding on N addition, and the role of P.  相似文献   

Inoculation of pines with mycorrhizal fungi in natural soils—III: Effect of soil fumigation on rate of infection and response to inoculum density     

R.J. Lamb  B.N. Richards 《Soil biology & biochemistry》1978,10(4):273-276

Pinus radiata seedlings were inoculated with basidiospores of Rhizopogon roseolas and Suillus granulatus, and with chlamylospores of two unidentified but highly effective mycorrhizal fungi in undisturbed cores of natural soil fumigated with methyl bromide. Fumigation stimulated mycorrhizal infection rate and enhanced the response of seedlings to increasing concentrations of both inoculum types, but the effect of chlamydospore inoculum was more favoured by fumigation than that of basidio-spores. Chlamydospore inocula appear more sensitive to competitive and antagonistic soil microorganisms than basidiospores. Soil fumigation appears a necessary adjunct to the use of chlamydospores as inoculants in nurseries and is discussed in relation to nursery culture of pines.  相似文献   

Studies on Herpesvirus scophthalmi infection of turbot Scophthalmus maximus (L.): Histopathological observations     

R. H. Richards  J. S. Buchanan 《Journal of fish diseases》1978,1(3):251-258

Abstract. The histological features of the disease caused by infection of turbot by Herpesvirus scophthalmi are described. Infection of epidermal cells of skin and gill resulted in the formation of giant cells showing a variety of nuclear and cytoplasmic changes associated with the replication of the virus. The effects of the condition together with possible control measures are discussed.  相似文献   

Effect of reforestation on turnover of ¹⁵N-labelled nitrate and ammonium in relation to changes in soil microflora     

J.M. Jones  B.N. Richards 《Soil biology & biochemistry》1977,9(6):383-392

The effects of incubation time, vegetation type (represented by a pine plantation, a protected and a periodically burnt eucalypt forest), lime and finely ground pine needles on the transformation of (¹⁵NH₄)₂SO₄ and K¹⁵NO₃ were studied in incubation experiments with a sandy lateritic podzolic soil from south-east Queensland. Microorganisms were counted so as to relate N transformations to particular groups of microorganisms.The heterotrophic miroflora utilized NH⁺₄ as a source of N in preference to NO^?₃, and autotrophic nitrifiers seemed to be weak competitors for NH⁺₄. Lime caused a slight loss of NO^?₃ and this was accompanied by an increase in the population of denitrifying bacteria.Lime promoted immobilization of NH⁺₄ by heterotrophic bacteria and subsequent mineralization by nitrifying bacteria, but when pine needles were also added the nitrifiers were suppressed and immobilization by heterotrophic bacteria dominated. Pine needles alone stimulated fungi to immobilize NH⁺₄.While reforestation with exotic pines caused a loss of total-N there was evidence of increased turnover, i.e. more rapid immobilization and nitrification, in pine plantation soils. Prescribed burning also promoted nitrification while reducing total-N.  相似文献   

Inoculation of pines with mycorrhizal fungi in natural soils—I.: Effects of density and time of application of inoculum and phosphorus amendment on mycorrhizal infection     

R.J. Lamb  B.N. Richards 《Soil biology & biochemistry》1974,6(3):167-171

On two soils lacking fungi capable of forming mycorrhizas with Pinus, the addition of superphosphate at 40 kgP/ha greatly increased mycorrhiza formation in Pinus radiata D. Don and P. elliottii Little and Dorman. Phosphorus could be partially replaced by increasing inoculum density or avoiding delay in inoculation after sowing. Chlamydospores were less effective than basidiospores as inoculum except at the highest density and in the presence of added P. At low available P concn such as are common in Australian soils, the normal pattern of infection of new short roots is interrupted and re-infection from the soil is of greater importance. Survival of mycorrhizal fungi in the soil in the absence of the host may therefore be a critical factor in inoculation programs.  相似文献   

Identification of B-cell epitopes on the betanodavirus capsid protein   总被引：1，自引：0，他引：1  

Costa JZ  Adams A  Bron JE  Thompson KD  Starkey WG  Richards RH 《Journal of fish diseases》2007,30(7):419-426

The pepscan procedure was used to identify betanodavirus B-cell epitopes recognized by neutralizing mouse monoclonal antibodies (MAbs) and serum samples obtained from sea bass, Dicentrarchus labrax, naturally infected with betanodavirus. Pepscan was performed with a panel of thirty-four 12-mer synthetic peptides that mimicked the entire betanodavirus capsid protein. Sea bass serum samples reacted strongly with three regions of the capsid protein comprising amino acid residues 1-32, 91-162 and 181-212. The latter region was also recognized by neutralizing MAbs and coincided with a region of high antigenic propensity identified by an antigen prediction algorithm. These data suggest that a region of the betanodavirus capsid protein spanning amino acid residues 181-212 may represent a neutralization domain that could potentially be used to inform the development of nodavirus vaccines and immunodiagnostic reagents.  相似文献   

THE AMERICAN SOCIETY OF BIOLOGICAL CHEMISTS     

Richards AN 《Science (New York, N.Y.)》1912,35(892):195-197

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