Wheat grain yield and stability assessed through regional trials in the Eastern Gangetic Plains of South Asia     

Ram C. Sharma  G. Ortiz-Ferrara  J. Crossa  M. R. Bhatta  M. A. Sufian  J. Shoran  A. K. Joshi  R. Chand  Gyanendra Singh  R. Ortiz 《Euphytica》2007,157(3):457-464

Improving the level and stability of grain yield is the primary objective of wheat breeding programs in the Eastern Gangetic Plains (EGP) of South Asia. A regional wheat trial, the Eastern Gangetic Plains Yield Trial (EGPYT), was initiated by CIMMYT in collaboration with national wheat research programs in Bangladesh, Nepal, and India in 1999–2000 to identify wheat genotypes with high and stable grain yield, disease resistance, and superior agronomic traits for the EGP region. A set of 21 wheat experimental genotypes selected from a regional wheat screening nursery in South Asia, three improved widely grown cultivars (Kanchan, PBW343 and Bhrikuti), and one long-term cultivar (Sonalika) were tested at 9–11 sites in six wheat growing seasons (2000–2005) in the EGP. The 21 experimental genotypes were different in each year, whereas the four check cultivars were common. In each year, one or more of the experimental genotypes showed high and stable grain yield and acceptable maturity, plant height, and disease resistance compared to the check cultivars. Three improved cultivars have already been commercially released in the region through EGPYT and many germplasm lines have been used in the breeding programs as parents. Identification of wheat genotypes with high-grain yield in individual sites and high and stable yield across the EGP region underlines their value for regional wheat breeding programs attempting to improve grain yield and agronomic performance.  相似文献   

The origin of polyploids via 2n gametes in Vaccinium section Cyanococcus     

Rodomiro Ortiz  Leo P. Bruederle  Timothy Laverty  Nicholi Vorsa 《Euphytica》1991,61(3):241-246

Summary The production of 2n pollen (pollen with the sporophytic chromosome number) was evaluated in 4x and 6x taxa of Vaccinium section Cyanococcus. Mean frequencies of 2n pollen producers were 17.1% and 8.3% in natural 4x and 6x populations, respectively. The frequency of 2n pollen producers in the 4x species ranged from 8.6% (V. angustifolium) to 23.8% (V. pallidum). Level of 2n pollen production was genotypically variable (1% to 37.4%). The widespread occurrence of 2n pollen in 2x, 4x and 6x taxa suggests that sexual polyploidization was widespread and responsible for the origin of the polyploid species found in this genus. The frequency of 2n pollen producers was not significantly different between the 4x species and their putative 2x ancestors. These results support the origin of 4x and 6x taxa as a consequence of sexual polyploidization. Polyploids derived from sexual polyploidization would be expected to have increased fitness and flexibility due to the mode of 2n pollen formation. In blueberry species the predominant mode of 2n pollen formation is genetically equivalent to a first division restitution mechanism (FDR). FDR 2n pollen transmits a high percentage of the heterozygosity and a large fraction of the epistasis from the 2x parent to the 4x offspring.  相似文献   

Improvement of durum wheat-plant type,yield potential,and adaptation     

Dietrich E. Leihner  Guillermo Ortiz F. 《Euphytica》1978,27(3):785-799

Summary Improvement of durum wheat at the International Maize and Wheat Improvement Center (CIMMYT) was achieved by exploiting the variability of the tetraploid species in large numbers of combinations, and multi-location testing of germplasm on a world wide base. High yielding, widely adapted durums with short straw, good fertility, and adequate earliness were selected for distribution to major durum growing countries. Present attempts to improve durum wheat are directed at adjusting agronomic traits such as leaf angle and straw strength, and increasing spike fertility and spike size, thereby reaching higher grain numbers per unit area and higher yield potential. Diversification of the developmental pattern and incorporation of drought tolerance aim at further widening adaptation.  相似文献   

Breeding gains and changes in morphotype of Nordic spring wheat (1901–1993) under contrasting environments     

Rodomiro Ortiz  Birgitte Lund  Sven-Bode Andersen 《Genetic Resources and Crop Evolution》2003,50(5):455-459

Phenotypic diversity among 75 Nordic spring wheat cultivars was assessed in a glasshouse experiment, in which plots had no fertilizer or received 14-3-23 NPK plus Mg. On average, the fertilizer application delayed flowering by one day, shortened plant height (PH), as well as enhanced the number of fertile tillers (NFT), fresh and dry straw weight (FSW and DSW, respectively), but influenced negatively the dry matter content in the straw (DMCS) and the number of kernels per spike (K/S). The cultivar-by-fertilizer interaction did not affect significantly days to flowering (DF), PH, FSW, DSW, DMCS, thousand kernel weight, and K/S. Only NFT was significantly affected by this interaction. There were significant differences among cultivars for all characteristics, and the breeding gains were significant for improving earliness (as determined by DF), shortening PH, as well as for reducing DSW and DMCS irrespective of the environment. On average, FSW was low in newer cultivars grown in high inputs, while NFT was low in newer cultivars when grown in low inputs. The country of origin affected significantly DF, PH, DMCS, K/S, and 1000-kernel weight. On average, cultivars developed for Finland and Norway were significantly taller, and had higher DMCS. Finnish cultivars also flowered 1 or 2 days earlier and showed higher K/S than cultivars adopted in southern Scandinavia or Norway.  相似文献   

Accurate determination of 2,4,6-trichloroanisole in wines at low parts per trillion by solid-phase microextraction followed by GC-ECD   总被引：1，自引：0，他引：1  

Alzaga R  Ortiz L  Sánchez-Baeza F  Marco MP  Bayona JM 《Journal of agricultural and food chemistry》2003,51(12):3509-3514

A headspace solid-phase microextraction (HS-SPME) procedure at 30 degrees C with a 100 microm PDMS fiber of a saturated NaCl solution stirred at 1100 rpm combined to GC-ECD for the 2,4,6-trichloroanisol (TCA) determination in wines has been developed. Due to the matrix complexity and ethanol absorption into the fiber, the internal standard selection was crucial to obtain unbiased results. Thus, matrix effects were observed when analyzing different types of Spanish wines (white, early, and vintage red wines) spiked with TCA at low concentration levels (i.e., <40 ng L(-)(1)). In contrast, the use of 2,4,6-tribromoanisole (TBA) as internal standard overcame these matrix effects, whereas the use of 2,4,6-trichlorophenyl ethyl ether led to inconsistent results. The developed HS-SPME-GC-ECD methodology reaches a limit of quantitation for TCA in wine within 2.9-18 ng L(-)(1), with a relative standard deviation of 2.5-13.4%, depending on the TCA concentration level and wine characteristics. This analytical method is comparable to the existing methodologies based on HS-SPME followed by GC-MS in terms of accuracy, precision, length of determination, and length of quantification; however, analysis cost is reduced.  相似文献   

Ciliates in a waste stabilization pond system in Mexico     

Fermin Rivera  M. Rosario Sanchez  Alfonso Lugo  Pedro Ramirez  Ricardo Ortiz  Arturo Calderon 《Water, air, and soil pollution》1987,34(3):245-262

A protozoological survey was performed on a waste-stabilization pond to isolate, identify, and determine the incidence of ciliates present in these waters. The correlation between the species found and the physicochemical parameters was investigated. One hundred and eighty samples were analyzed from February 1983 to February 1984. Free-living ciliates isolated include:Carchesium polypinum Linnaeus,Vorticella microstoma Ehrenberg,Vorticella convallaria Linnaeus,Didinium balbiani Fabré-Domergue,Amphileptus claparedei Stein,Spathidium spathula Müller,Litonotus fasciola Ehrenberg,Paramecium caudatum Müller,Paramecium aurelia Ehrenberg,Tetrahymena vorax Kidder,Tetrahymena pyriformis Ehrenberg,Cyclidium glaucoma Müller,Aspidisca costata Ehrenberg, andStylonychia putrina Stokes. The performance of the pond was predominantly anaerobic. The temperature, total alkalinity, and nitrate concentration were the most variable parameters in the system studied.  相似文献   

Effect of source germplasm and season on the in vivo haploid induction rate in tropical maize     

Aida Z. Kebede  Baldev S. Dhillon  Wolfgang Schipprack  Jose L. Araus  Marianne Bänziger  Kassa Semagn  Gregorio Alvarado  Albrecht E. Melchinger 《Euphytica》2011,180(2):219-226

For in vivo production of doubled haploid (DH) lines in maize, the rate of haploid induction is of crucial importance. Maternal haploid induction depends primarily on the inducer used as a pollinator. However, the source germplasm used as a maternal parent and the environmental conditions for induction may also influence haploid induction and these aspects have not been examined in tropical maize so far. The objectives of our study were to (i) monitor the variation for haploid induction rate (HIR) among diverse source germplasm in tropical maize, (ii) determine the relative importance of general (GCA) and specific (SCA) combining abilities for HIR, and (iii) investigate the influence of summer and winter seasons and genotype × season interactions on this trait. Ten inbreds were mated in a half diallel design. The resulting 45 F₁ single crosses were pollinated with the haploid inducer hybrid RWS × UH400 during the summer 2008 and winter 2009 seasons in a lowland tropical environment in Mexico. HIR of the single crosses averaged over seasons ranged from 2.90 to 9.66% with an overall mean of 6.74%. Mean HIR was significantly (P < 0.01) higher during the winter (7.37%) than summer season (6.11%). Significant (P < 0.01) variation was observed due to GCA effects of parental inbreds of single crosses but not for SCA, GCA × season and SCA × season interactions. Our study underpins that a higher HIR in tropical maize can be obtained by selecting appropriate source germplasm and undertaking pollination under favorable environmental conditions.  相似文献   

A rubberlike stretchable active matrix using elastic conductors     

Sekitani T  Noguchi Y  Hata K  Fukushima T  Aida T  Someya T 《Science (New York, N.Y.)》2008,321(5895):1468-1472

By using an ionic liquid of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, we uniformly dispersed single-walled carbon nanotubes (SWNTs) as chemically stable dopants in a vinylidene fluoride-hexafluoropropylene copolymer matrix to form a composite film. We found that the SWNT content can be increased up to 20 weight percent without reducing the mechanical flexibility or softness of the copolymer. The SWNT composite film was coated with dimethyl-siloxane-based rubber, which exhibited a conductivity of 57 siemens per centimeter and a stretchability of 134%. Further, the elastic conductor was integrated with printed organic transistors to fabricate a rubberlike active matrix with an effective area of 20 by 20 square centimeters. The active matrix sheet can be uniaxially and biaxially stretched by 70% without mechanical or electrical damage. The elastic conductor allows for the construction of electronic integrated circuits, which can be mounted anywhere, including arbitrary curved surfaces and movable parts, such as the joints of a robot's arm.  相似文献   

Varietal discrimination and genetic relationships of Vitis vinifera L. cultivars from two major Controlled Appellation (DOC) regions in Portugal     

Isaura Castro  Juan Pedro Martín  Jesús Maria Ortiz  Olinda Pinto-Carnide 《Scientia Horticulturae》2011

Thirty-nine grapevine cultivars widely grown in Portugal, especially in Vinhos Verdes and Douro regions, and two well known international cultivars as standards, were genotyped at 12 microsatellite loci. The number of alleles per locus ranged from 6 to 12, and the number of allelic combinations per locus from 13 to 26. The total number of unique genotypes in the 12 analysed loci was 120, having most of the cultivars (38 out of 41) at least one unique genotype in any of the loci. The microsatellite profiles were adequate to discriminate 41 cultivars. The level of observed heterozygosity at each locus varied from 70.7% to 95.1%. VVMD28 has been revealed as one of the most informative markers. Several synonymies between Spanish and Portuguese cultivars were confirmed, and some homonymies are discussed. The genetic profiles of all 41 cultivars were searched for possible parent-offspring groups. The data obtained revealed the possible descendence of Touriga Franca from Touriga Nacional and Marufo.  相似文献   

Effect of differently post-treated dewatered sewage sludge on β-glucosidase activity,microbial biomass carbon,basal respiration and carbohydrates contents of soils from limestone quarries     

P. Jiménez  O. Ortiz  D. Tarrasón  M. Ginovart  M. Bonmatí 《Biology and Fertility of Soils》2007,44(2):393-398

This work has evaluated the effects of thermally dried (TDS) or composted (CDS) dewatered sewage sludge on β-glucosidase activity, total (TCH) and extractable (ECH) carbohydrate content, microbial biomass carbon and basal respiration of soils from limestone quarries under laboratory conditions. Two doses (low and high) of the dewatered sludge (DS) or of the respective TDS or CDS were applied to a clayey and a sandy soil, both coming from working quarries. The soil mixtures and the controls (soils with no added sludge) were incubated for 9 months at 25°C and 30% of field capacity. The addition of sludge increased all the studied soil parameters, and the increase depended on the amount of sludge. Except in the case of TCH and ECH, the enhancing effect decreased with time, but at the end of incubation, parameters of the treated soils were higher than those of the control. The rank order of the initial stimulating effect was soil–TDS ≥ soil–DS ≥ soil–CDS, and probably, this order depended on the proportion of stable organic matter, which was the lowest in the TDS. Values of metabolic quotient (qCO₂) were higher at the lower dose, and they did not change during incubation in the CDS-treated soils. Both TCH and ECH were the parameters with the greatest significant sludge and dose effects. Basal respiration, microbial biomass carbon and β-glucosidase activity were the best measured parameters in distinguishing the long-term effects of the three sludge types over the soils.  相似文献