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排序方式: 共有295条查询结果,搜索用时 15 毫秒
241.
242.
I. S. A. Tahir N. Nakata A. M. Ali H. M. Mustafa A. S. I. Saad K. Takata N. Ishikawa O. S. Abdalla 《Plant Breeding》2006,125(4):323-330
High temperature influences both grain yield and end‐use quality of wheat. The objectives of this study were to evaluate the performance of selected wheat genotypes under heat stress and to examine the effects of high temperatures during grain filling on grain yield and end‐use quality parameters. Fifteen bread wheat genotypes in 2000/2001 and 18 genotypes in 2002/2003 were evaluated under the optimum and late‐sowing conditions of the irrigated hot environment of the Gezira Research Farm, Wad Medani, Sudan. The genotypes comprised released varieties and elite lines from the Sudanese wheat improvement programme. Data collected included grain yield, grain weight and grain end‐use quality including protein content, protein composition, SDS sedimentation values (SDSS) and gluten strength as determined by mixograph analyses. High temperatures significantly decreased grain yield by decreasing grain weight. Although genotypes exhibited variation in magnitude of response, results indicated that high temperature during grain filling increased both soluble and insoluble protein contents, SDSS, mixograph peak height (MPH) and the descending slope at 2 min past peak (MDS). In contrast, mixograph peak time (MPT) and the curve width at 2 min past peak (MCW) were significantly decreased. Flour protein correlated positively with SDSS, MPH and MDS and negatively with MCW. MPT correlated negatively with MDS and positively with MCW. Results indicate that high temperature increased both soluble and insoluble protein contents, SDSS and MPH, and hence the gluten strength, but decreased flour mixing time and tolerance and hence the dough elasticity. Variation observed among genotypes suggests that grain end‐use quality could be improved under high temperature conditions utilizing the available variability; however, it might require evaluation under various growing conditions. 相似文献
243.
Thirty progenies of mungbean were produced by crossing 10 true-breeding genotypes with three testers (NM 92, 6601, and their
F1) in a Triple Test cross (TTC) fashion and evaluated with parents in the kharif (July-October) and spring/summer (March-June)
seasons. The data on parents and F1s were analysed for pod clusters on main stem, pod clusters on branches, node of the first peduncle, nodes on main stem and
average internode length to detect epistasis and estimate additive and dominance components of genetic variation. Epistasis
was observed for node of the first peduncle and nodes on main stem in the kharif season. Partitioning of total epistasis revealed
that both additive × additive (i type), and additive × dominance, and dominance × dominance (j and l types) interactions were
significant with prevalent influence of i type interactions on these traits. Both additive and dominance components of genetic
variation were significant for all those traits not significantly influenced by epistasis in either or both seasons. The additive
component was predominant for pod clusters on main stem, pod clusters on branches and average internode length in the kharif
season, and for the node of the first peduncle and nodes on main stem in spring/summer season whereas dominance component
was important for pod clusters on main stem, pod clusters on branches, and average internode length in spring/summer season.
These results suggested that particular generation of segregating population and specific breeding method for selection might
be adopted in each season for the improvement of these traits in mungbean.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
244.
Relationship between cold resistance,heading traits and ear primordia development of wheat cultivars
Summary For breeding early heading wheat cultivars with resistance to frost damage which are well adapted to dry areas of West Asia and North Africa, the relationships between winter hardiness, ear primordia development and heading traits, i.e. veernalization requirement, photoperiodic response and narrow-sense earliness, were assessed using a total of 30 genotypes of wheat (Triticum aestivum L.) grown in an experiment in Syria. The results of artificial freezing tests indicated that cultivars with good winter hardiness were to be found only in the winter wheat cultivars which required 50 or more days of vernalization treatment. These winter wheat cultivars did not initiate internode elongation without vernalization even at 95 days after planting. Thus their ear primordia were still underground and were protected from frost injury at this stage. Photoperiodic response and narrow-sense earliness were not associated with winter hardiness and earliness of internode elongation, but were related to the number of days to heading after planting. This indicated the possibility for breeding early heading cultivars with winter hardiness and tiller frost avoidance by combining high vernalization requirement, short narrow-sense earliness and neutral response to photoperiod. 相似文献
245.
Tariq Mahmood Muhammad H. Rahman Gary R. Stringam Francis Yeh Allen Good 《Euphytica》2005,144(1-2):157-167
A population of 112 F1-derived doubled haploid lines was produced from a reciprocal cross of Brassica juncea. The parents differed for seed quality, seed color and many agronomic traits. A detailed RFLP linkage map of this population,
comprising 316 loci, had been constructed, and was used to map quantitative trait loci (QTL) for seed yield and yield components,
viz. siliqua length, number of seeds per siliqua, number of siliques per main raceme and 1000-seed weight. Stable and significant
QTLs were identified for all these yield components except seed yield. For yield components, a selection index based on combined
phenotypic and molecular data (QTL effects) could double up the efficiency of selection compared to the expected genetic advance
by phenotypic selection. Selection indices for high seed yield, based on the phenotypic data of yield and yield components,
could only improve the efficiency of selection by 4% of the genetic advance that can be expected from direct phenotypic selection
for yield alone. Inclusion of molecular data together with the phenotypic data of yield components in the selection indices
did not improve the efficiency of selection for higher seed yield. This is probably due to often negative relationships among
the yield components. Most of the QTLs for yield components were compensating each other, probably due to linkage, pleiotropy
or developmentally induced relationships among them. The breeding strategy for B. juncea and challenges to marker assisted selection are discussed. 相似文献
246.
The effects of NaCl on the growth, ion relations and physiological characteristics at early stages of growth of bread wheat (Triticum aestivum) varieties ‘Chinese Spring’ and ‘Glennson 81’, ‘Chinese Spring’ lines tetrasomic for chromosomes 5A, 2B and 5B, ‘Chinese Spring’ disomic addition lines for chromosomes 2Eb and 5Eb from Thinopyrum bessarabicum (formerly Agropyron junceum), and amphiploids between ‘Chinese Spring’ and Thinopyrum bessarabicum and ‘Chinese Spring’ and Lophopyrum elongatum (formerly Agropyron elongatum) were examined. Plants were grown in a controlled environment cabinet, in nutrient solution with or without addition of 200 mol m?3 NaCl. Growth in terms of leaf area, shoot and root weights was reduced by salt treatment. Salinity conditions gradually reduced the osmotic potential, though there was little effect on water potential. Turgor pressure was not much affected by salt. There was variation between genotypes for all the characteristics studied, especially in the extent of Na accumulation by leaves and roots. The amphiploids and 5Eb addition line accumulated the least Na in comparison with other genotypes. Generally roots accumulated lower quantities of Na than leaves. Genotype K contents were not affected by salt treatment. Stomatal conductance also declined whilst the ABA content increased in the salt treated seedlings. With respect to growth, the amphiploids and 5Eb addition line were most tolerant to salt while ‘Glennson 81’, tetrasomic 2B and tetrasomic 5B lines were most susceptible. The addition of homoeologous group 2 and 5 chromosomes reduced the tolerance to salt relative to ‘Chinese Spring’ euploid. It is concluded that chromosome 5Eb of Thinopyrum bessarabicum carries gene(s) for tolerance to salt and this tolerance may be due to the ability to exclude Na ions from the leaves and roots. 相似文献
247.
248.
John H. Loughrin Arturo I. Quintanar Nanh C. Lovanh Rezaul Mahmood 《Water, air, and soil pollution》2011,216(1-4):463-471
The number of chemical compounds in sewage and consequently their release into the environment is increasing. Some of them are toxic and many of them are considered endocrine disrupters. Here, the capacity of three wastewater treatment plants (WWTPs) to remove caffeine, hormones and bisphenol-A was investigated. Bisphenol-A and caffeine are highly water-soluble compounds, as opposed to hormones (estradiol, estriol, and ethynilestradiol) which are hydrophobic compounds. In the Sewage Treatment Plant (SWT)1 the sewage is treated by activated sludge process, in the second plant, SWT2, sewage is treated by upflow anaerobic sludge blanket reactors followed by dissolved air flotation, and in the third, SWT3 sewage is treated by stabilization lagoons. The first lagoon is 3.5 m deep, thus facultative and polishment processes occur. It was speculated that there was a difference in efficiency between the three plants in removing micropollutants. Small differences were found in the amounts removed, probably accounted for by retention time. The caffeine and bisphenol-A were almost completely removed, higher than 90% for both compounds (bisphenol-A and caffeine) in all WWTPs. The hormones, however, had a smaller rate of removal, between 70% and 87%. It is suspected that retention time is essential for removal efficiency, together with type of treatment. In fact, the hormones, caffeine, and bisphenol-A found in the environment definitely come from untreated sewage. 相似文献
249.
Mahmood R Golzarian Ross A Frick Karthika Rajendran Bettina Berger Stuart Roy Mark Tester Desmond S Lun 《Plant methods》2011,7(1):2
With the establishment of advanced technology facilities for high throughput plant phenotyping, the problem of estimating
plant biomass of individual plants from their two dimensional images is becoming increasingly important. The approach predominantly
cited in literature is to estimate the biomass of a plant as a linear function of the projected shoot area of plants in the
images. However, the estimation error from this model, which is solely a function of projected shoot area, is large, prohibiting
accurate estimation of the biomass of plants, particularly for the salt-stressed plants. In this paper, we propose a method
based on plant specific weight for improving the accuracy of the linear model and reducing the estimation bias (the difference
between actual shoot dry weight and the value of the shoot dry weight estimated with a predictive model). For the proposed
method in this study, we modeled the plant shoot dry weight as a function of plant area and plant age. The data used for developing
our model and comparing the results with the linear model were collected from a completely randomized block design experiment.
A total of 320 plants from two bread wheat varieties were grown in a supported hydroponics system in a greenhouse. The plants
were exposed to two levels of hydroponic salt treatments (NaCl at 0 and 100 mM) for 6 weeks. Five harvests were carried out.
Each time 64 randomly selected plants were imaged and then harvested to measure the shoot fresh weight and shoot dry weight.
The results of statistical analysis showed that with our proposed method, most of the observed variance can be explained,
and moreover only a small difference between actual and estimated shoot dry weight was obtained. The low estimation bias indicates
that our proposed method can be used to estimate biomass of individual plants regardless of what variety the plant is and
what salt treatment has been applied. We validated this model on an independent set of barley data. The technique presented
in this paper may extend to other plants and types of stresses. 相似文献
250.
Muhammad Tahir Khan Nazir Ahmad Khan Melkamu Bezabih Muhammad Subhan Qureshi Altafur Rahman 《Tropical animal health and production》2013,45(3):849-853
The aim of this study was to evaluate the nutritional and feeding value of peanut hay (Arachis hypogaea L.) produced under tropical environment as an alternate forage resource for sheep. Peanut hay was appreciably high in crude protein [CP; 105 g/kg dry matter (DM)] and lower in neutral detergent fiber (NDF; 466 g/kg DM). Moreover, peanut hay was rich in Ca (12 g/kg DM) and P (1.7 g/kg DM). A feeding trial was conducted to investigate the effect of substituting wheat straw with peanut hay on nutrient intake, digestibility, and N utilization. Four adult Ramghani (Kaghani × Rambouillet) wethers (60?±?2.5 kg body weight) were randomly assigned to the four dietary treatments according to a 4?×?4 Latin square design. The four rations were formulated on isonitrogenous and isocaloric bases and differed in the proportion (in grams per kilogram DM) of wheat straw/peanut hay, i.e., 700:0, 460:240, 240:460, and 0:700. The replacement of wheat straw with peanut hay increased the intakes of DM (P?<?0.001), NDF (P?<?0.01), and N (P?<?0.001). Moreover, apparent in vivo digestibility of DM, NDF, and CP increased (P?<?0.001) with the increasing proportion of peanut hay in the ration. Nitrogen retention in the body increased (P?<?0.01; 3.2 to 8.1 g/day) with the replacement of wheat straw with peanut hay. These findings showed that substitution of wheat straw with peanut hay can improve DM and nutrients intake, digestibility, and N retention in sheep. 相似文献