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41.
水稻株高QTL分析及其与产量QTL的关系   总被引:18,自引:6,他引:18  
分别应用具有112和160个标记位点的两个籼/籼交组合的F2群体的连锁图,对控制水稻株高的数量性状基因(QTL)进行了研究.各定位了4个和3个株高QTL,每个QTL的贡献率在5.6%~22.9%之间.在一个群体中,4个QTL都表现为完全显性或超显性;在另一个群体中,3个QTL均表现为部分显性.分别检测到7对和5对影响株高的双基因互作,其中一个群体以  相似文献   
42.
We evaluated stereotactic volume modulated arc radiotherapy (VMAT) for canine gliomas, alone (radiotherapy [RT]) and in combination with temozolomide (RT + TMZ), compared with palliation. Overall and disease‐specific survival times were estimated. Thirty dogs were palliated, 22 dogs were treated with RT and 20 with RT + TMZ. Complete and partial responses were observed in 63.2% and 90.9% of patients in the RT and RT + TMZ arms, respectively, that were alive at 1 year. Median survival in the palliation arm was 94 days (95% conformity index [CI] 87÷101). Median survivals of the RT arm (383 days, 95% CI 276÷490) and RT+TMZ arm (420 days, 95% CI 280÷560) were not significantly different (P = .61). Positive correlation with survival was found both for the ratio between target and brain (relative) volume of the tumour of <5% (P = .013) and for a clinical presentation with normal mentation (P = .032). VMAT is feasible and effective for canine brain gliomas. Combining this therapy with TMZ did not elicit any additional improvement in survival time.  相似文献   
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Pregnant sow nutrition has potential effects on the muscle fiber development of progeny in utero. A total of 199 Landrace x Large White sows from parities 0 to 6 and their offspring were used to evaluate the effects of increasing the feeding amount during midpregnancy on the muscle tissue, growth performance, and meat quality of the progeny. The experiment was divided into 2 study replicates, and in each replicate, sows were assigned to 1 of the 2 treatments: 1) sows in the control group (C sows) were fed 2.5 to 3.0 kg/d (feed: 12.1 MJ of ME/kg and 0.62% lysine) throughout gestation; and 2) sows in the high group (H sows) received an extra feed allowance of 1.5 kg/d for gilts and 2.0 kg/d for multiparous sows above the C amount from d 45 to 85 of gestation (period of secondary muscle fiber formation). Sow backfat was recorded on d 40 and 85 of gestation. Sow performance (litter size and piglet BW) at farrowing and on d 18 of lactation was measured. At weaning, pigs were divided into 5 BW groups/treatment, and progeny growth performance was measured during the nursery (n = 958) and the growing-finishing (n = 636) periods. At slaughter, carcass and meat quality traits (lean content, main cut weight, pH, Minolta color, and drip loss) were recorded from the second lightest group at weaning (BW group 4; n = 90), and samples from the longissimus thoracis muscle were taken to study muscle fiber characteristics (n = 70). The extra nutrition from d 45 to 85 of gestation did not lead to differences in litter size or piglet BW at farrowing and on d 18 of lactation. Pigs born to H mothers had fewer muscle fibers and fewer estimated primary and secondary fibers than did pigs born to C mothers (P < 0.05). However, postnatal growth performance was not consistently affected by the maternal treatment. The smaller number of muscle fibers found in the H group of pigs was associated with fewer type IIB fibers (P < 0.05) with greater cross-sectional areas (P < 0.10), which might be related to the significantly greater meat pH at 24 h postmortem and the smaller L* (lightness) values recorded in the H group of pigs. Results from the present study confirm the existence of effects of maternal nutrition on fetal development, at least in terms of muscle tissue development and meat quality, although with no beneficial effects were found for the postnatal growth performance of the progeny.  相似文献   
46.
The concept that superconductivity competes with other orders in cuprate superconductors has become increasingly apparent, but obtaining direct evidence with bulk-sensitive probes is challenging. We have used resonant soft x-ray scattering to identify two-dimensional charge fluctuations with an incommensurate periodicity of ~3.2 lattice units in the copper-oxide planes of the superconductors (Y,Nd)Ba(2)Cu(3)O(6+)(x), with hole concentrations of 0.09 to 0.13 per planar Cu ion. The intensity and correlation length of the fluctuation signal increase strongly upon cooling down to the superconducting transition temperature (T(c)); further cooling below T(c) abruptly reverses the divergence of the charge correlations. In combination with earlier observations of a large gap in the spin excitation spectrum, these data indicate an incipient charge density wave instability that competes with superconductivity.  相似文献   
47.
E. R. Carmona    A. D. Arencibia    J. Lopez    J. Simpson    D. Vargas  F. Sala 《Plant Breeding》2005,124(1):33-38
Three transgenic sugarcane populations produced by Agrobacterium tumefaciens infection were analysed for the presence of genomic variability. Plants of the original cultivar, plants regenerated without transformation, as well as transformed and untransformed calli were used as control treatments. Amplified fragment length polymorphism (AFLP) of DNA extracted from leaves or calli assessed genomic profiling. The average DNA polymorphism within each population was determined by calculating the polymorphism index, while the extent of genomic dissimilarity among individual plants within transgenic populations was verified in unweighted pair group method using arithmetic averages dendrograms. The results showed that the production of transgenic sugarcane plants by A. tumefaciens infection is accompanied by limited but detectable genomic changes and that, on average, these occur at the same rate in plant populations carrying different transgenes. Main factors contributing to somaclonal variation in transgenic sugarcane plants have been verified by pre-existing DNA polymorphism into the donor genotype and in vitro culture steps during the transformation procedure. The relevant practical conclusion from this finding is that the AFLP analysis may be effectively used to identify individual transgenic plants with the least genomic deviation from the parental ones. The selected genotype would be conserved as cultivated sugarcane is asexually propagated.  相似文献   
48.
T. Fossati    G. Patrignani    I. Zapelli    M. Sabatti    F. Sala  S. Castiglione 《Plant Breeding》2004,123(4):382-385
Morphological traits traditionally adopted to discriminate between Populus alba L. and P. tremula L. have frequently led to misclassifi‐cation of their spontaneous hybrid P. × canescens Sm. Moreover, they may not be of any help in cases of spontaneous backcross phenomena. These limitations can be overcome by molecular markers, which are not environmentally influenced nor subjectively assessed. In this study, the effectiveness of amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers in species and hybrid discrimination was evaluated by analysing a set of reference samples of P. alba, P. tremula and P. × canescens. Species‐specific and species‐indicative AFLPs, as well as diagnostic SSR alleles, were recorded in both P. alba and P. tremula reference samples. The results allowed a clear distinction between the two poplar species and their hybrid. Using these diagnostic markers, a natural population of P. alba trees sampled along the Ticino river basin in northern Italy was analysed, and P. × canescens individuals, intermingled with P. alba trees, were detected.  相似文献   
49.
Management of N fertilization depends not only on the mineral N measured at the beginning of the growing season but also on the status of the low-molecular-weight organic-N fraction. Our study was conducted to analyze how much of the 15N applied in labeled cornshoot tissue would be recovered in 0.01 M CaCl2-extractable 15N fractions and wheter a decrease in the CaCl2-extractable 15N fraction quantitatively followed the trend in net mineralization of the 15N applied in corn-shoot tissue during an incubation period. The effects of adding 15N-labeled young corn-shoot tissue to a sandy soil and a clay soil were investigated for 46 days in an aerobic incubation experiment at 25°C. The application of 80 mg N kg-1 soil in the form of labeled corn-shoot tissue (24.62 mg 15N kg-1 soil) resulted in a significant initial increase, followed by a decrease the labeled organic-N fraction in comparison with the untreated soils during the incubation. The labeled organic-N fraction was significantly higher in the sandy soil than in the clay soil until the 4th day of incubation. The decrease in labeled organic N in the sandy soil resulted in a subsequent increase in 15NO inf3 sup- during the incubation. Ammonification of applied plant N resulted in a significant increase in the 1 M HCl-extractable non-exchangeable 15NH inf4 sup+ fraction in the clay soik, owing to the vermiculite content. The 15N recovery was analyzed by the 0.01 M CaCl2 extraction method; at the beginning of the incubation experiment, recovery was 37.0% in the sandy soil and 36.7% in the clay soil. After 46 days of incubation, recovery increased to 47.2 and 43.8% in the sandy and clay soils, respectively. Net mineralization of the 15N applied in corn-shoot tissue determined after the 46-day incubation was 6.60 mg 15N kg-1 soil (=34.9% of the applied organic 15N) and 4.37 mg 15N kg-1 soil (=23.1% of the applied organic 15N) in the sandy and the clay soils, respectively. The decrease in the labeled organic-N fraction extracted by 0.01 M CaCl2 over the whole incubation period was 3.14 and 2.33 mg 15N kg-1 soil in the sandy and clay soil, respectively. These results indicate that net mineralization of 15N was not consistent with the decrease in the labeled organic-N fraction. This may have been due to the inability of 0.01 M CaCl2 to extract or desorb all of the applied organic 15N that was mineralized during the incubation period.  相似文献   
50.
The objective of this experiment was to assess the features and extent of follicular apoptosis in the water buffalo (Bubalus bubalis) ovary using classical histology and nick end labelling technique. Ovaries (n = 40) procured from the slaughterhouse were used for the study. The sections (5 μm) were used for detection of terminal deoxynucleotidyl transferase‐mediated dUTP‐biotin nick end labelling (TUNEL) and classical histology (H&E). Those follicles showing ≥ 5% TUNEL positivity (TUNEL assay) and pyknotic nuclei (histology) in granulosa cells were classified as atretic. Based on histology, the atretic primary and secondary follicles (%) were 93.82 and 95.62 respectively. The histology study reveals that the rates (%) of atresia in <1, 1–3, 3–5 mm and >5 mm were 36.90, 40.50, 62.84 and 74.5 respectively. Further the atretic tertiary follicles (%) were significantly lower than the primary and secondary classes of follicles. TUNEL assay reveals that the atretic rate (%) of tertiary follicles in <1, 1–3, 3–5 and ≥ 5 mm class follicles were 50.88, 53.84, 81.81 and 36.36 respectively. The percentage of atresia in >5 mm diameter follicles were significantly lower in TUNEL than histology. Percentages of granulosa and thecal cells positive for atresia by TUNEL were 30.7 ± 0.53 and 13.82 ± 0.18 respectively per follicle. The initial structural changes in atretic follicles were seen primarily in the granulosa cells. In severely atretic follicles TUNEL positive granulosa cells along with theca cells have to be considered in assessing the rate and extent of atresia.  相似文献   
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