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The density inversion of gravity gradiometry data has attracted considerable attention; however, in large datasets, the multiplicity and low depth resolution as well as efficiency are constrained by time and computer memory requirements. To solve these problems, we improve the reweighting focusing inversion and probability tomography inversion with joint multiple tensors and prior information constraints, and assess the inversion results, computing efficiency, and dataset size. A Message Passing Interface (MPI)-Open Multi-Processing (OpenMP)-Computed Unified Device Architecture (CUDA) multilevel hybrid parallel inversion, named Hybrinv for short, is proposed. Using model and real data from the Vinton Dome, we confirm that Hybrinv can be used to compute the density distribution. For data size of 100×100×20, the hybrid parallel algorithm is fast and based on the run time and scalability we infer that it can be used to process the large-scale data.

This research proposes a novel three-dimensional gravity inversion based on sparse recovery in compress sensing. Zero norm is selected as the objective function, which is then iteratively solved by the approximate zero norm solution. The inversion approach mainly employs forward modeling; a depth weight function is introduced into the objective function of the zero norms. Sparse inversion results are obtained by the corresponding optimal mathematical method. To achieve the practical geophysical and geological significance of the results, penalty function is applied to constrain the density values. Results obtained by proposed provide clear boundary depth and density contrast distribution information. The method’s accuracy, validity, and reliability are verified by comparing its results with those of synthetic models. To further explain its reliability, a practical gravity data is obtained for a region in Texas, USA is applied. Inversion results for this region are compared with those of previous studies, including a research of logging data in the same area. The depth of salt dome obtained by the inversion method is 4.2 km, which is in good agreement with the 4.4 km value from the logging data. From this, the practicality of the inversion method is also validated.

Based-on the previous study on the theory of the sequential pyramid wavefront sensor (SPWFS), in this paper, the SPWFS is first applied to the coherent free space optical communications (FSOC) with more flexible spatial resolution and higher sensitivity than the Shack-Hartmann wavefront sensor, and with higher uniformity of intensity distribution and much simpler than the pyramid wavefront sensor. Then, the mixing efficiency (ME) and the bit error rate (BER) of the coherent FSOC are analyzed during the aberrations correction through numerical simulation with binary phase shift keying (BPSK) modulation. Finally, an experimental AO system based-on SPWFS is setup, and the experimental data is used to analyze the ME and BER of homodyne detection with BPSK modulation. The results show that the AO system based-on SPWFS can increase ME and decrease BER effectively. The conclusions of this paper provide a new method of wavefront sensing for designing the AO system for a coherent FSOC system.

In this paper, we make a study on the inversion of probability tomography (IPT) with gravity gradiometry data at first. The space resolution of the results is improved by multi-tensor joint inversion, depth weighting matrix and the other methods. Aiming at solving the problems brought by the big data in the exploration, we present the parallel algorithm and the performance analysis combining Compute Unified Device Architecture (CUDA) with Open Multi-Processing (OpenMP) based on Graphics Processing Unit (GPU) accelerating. In the test of the synthetic model and real data from Vinton Dome, we get the improved results. It is also proved that the improved inversion algorithm is effective and feasible. The performance of parallel algorithm we designed is better than the other ones with CUDA. The maximum speedup could be more than 200. In the performance analysis, multi-GPU speedup and multi-GPU efficiency are applied to analyze the scalability of the multi-GPU programs. The designed parallel algorithm is demonstrated to be able to process larger scale of data and the new analysis method is practical.

The subsurface three-dimensional (3D) model of density distribution is obtained by solving an under-determined linear equation that is established by gravity data. Here, we describe a new fast gravity inversion method to recover a 3D density model from gravity data. The subsurface will be divided into a large number of rectangular blocks, each with an unknown constant density. The gravity inversion method introduces a stabiliser model norm with a depth weighting function to produce smooth models. The depth weighting function is combined with the model norm to counteract the skin effect of the gravity potential field. As the numbers of density model parameters is NZ (the number of layers in the vertical subsurface domain) times greater than the observed gravity data parameters, the inverse density parameter is larger than the observed gravity data parameters. Solving the full set of gravity inversion equations is very time-consuming, and applying a new algorithm to estimate gravity inversion can significan...

The mechanical configuration of an independent pitch control system (IPCS) for coaxial dual-rotor compound helicopter (CDCH) was presented, which is mainly constituted by parallel mechanism, spatial orientation, lower rotor and upper rotor. The solving path and model division for the IPCS based on the working principle can be explained to achieve azimuth attitude precise control of upper and lower propeller for the CDCH. The completely mathematical model of attitude control system for the CDCH was obtained by using lumped parameters method and sub-total solution model which the forward and reverse positional attitude solution were deducted by the coordinate space transformation and kinematic analysis method. The co-simulation analysis which based on the MATLAB and Recurdyn software was done and the numerical comparative results show that the theoretical analysis of the mathematical model for attitude control system was reasonable and applicable by means of comparison with semi-physical model in the various boundary conditions and parameters of parallel mechanism, spatial orientation, lower rotor and upper rotor, respectively.

Borehole gravity is increasingly used in mineral exploration due to the advent of slim-hole gravimeters. Given the full-tensor gradiometry data available nowadays, joint inversion of surface and borehole data is a logical next step. Here, we base our inversions on cokriging, which is a geostatistical method of estimation where the error variance is minimised by applying cross-correlation between several variables. In this study, the density estimates are derived using gravity-gradient data, borehole gravity and known densities along the borehole as a secondary variable and the density as the primary variable. Cokriging is non-iterative and therefore is computationally efficient. In addition, cokriging inversion provides estimates of the error variance for each model, which allows direct assessment of the inverse model. Examples are shown involving data from a single borehole, from multiple boreholes, and combinations of borehole gravity and gravity-gradient data. The results clearly show that the depth resolution of gravity-gradient inversion can be improved significantly by including borehole data in addition to gravity-gradient data. However, the resolution of borehole data falls off rapidly as the distance between the borehole and the feature of interest increases. In the case where the borehole is far away from the target of interest, the inverted result can be improved by incorporating gravity-gradient data, especially all five independent components for inversion.

Degradation of bit-error-rate (BER), caused by atmospheric turbulence, seriously hinders the performance of coherent Free Space Optical (FSO) communication systems. An adaptive optics system proves to be effective in suppressing the atmospheric turbulence. The holographic modal wavefront sensor (HMWFS) proposed in our previous work, noted for its fast detecting rates and insensitivity to beam scintillation, is applied to the coherent FSO communication systems. In this paper, based on our previous work, we first introduce the principle of the HMWFS in brief and give the BER of the coherent FSO with homodyne detection in theory, and then analyze the improvement of BER for a coherent FSO system based on our previous simulation works. The results show that the wavefront sensor we propose is better for weak atmospheric turbulence. The most obvious advantages of HMWFS are fast detecting rates and insensitivity to beam scintillation.

For a coherent lidar, the efficiency of homodyne detection is a significant factor. Adaptive optics (AO) is an effective way to correct the turbulence-induced wavefront distortions. Based on our previous works, an expression for the homodyne detection efficiency is given. The results of the numerical simulation show that the atmospheric coherent length has an influence on the homodyne detection efficiency for a fixed atmospheric Greenwood frequency and a closed-loop control bandwidth. In addition, an experimental AO system is employed to verify the effect of the AO on the coherent lidar. The results show that the homodyne detection efficiency is obviously improved after aberrations are corrected. The conclusion of this paper provides a reference for designing an AO system for a coherent lidar.

Full tensor gradient (FTG) data is highly useful in hydrocarbon exploration and the detection of some geological targets with small size as its higher detailed information abundance and finer resolution. At the same time, there are some high-frequency Gaussian white noise mixed in the target signal and which has closer frequency range than the conventional gravity data. Thus, one key step before inversion is to remove as much Gaussian white noise as possible and reserve the subtle details. For this pre-processing step, several effective methods have been used, including low-pass filters, least square fitting methods based on Laplace equation and wavelet filtering methods. In this paper, we would utilize the translation invariant wavelet for the reason that it can suppress Gaussian white noise through multi-resolution analysis and at the same time can avoid pseudo-Gibbs phenomenon. The other point different from wavelet method used before is that we applied a mixed threshold constructed according to the curve of both soft threshold and hard threshold. Compared to soft and hard threshold, mixed threshold can keep more details and remove more noise respectively in terms of the energy distribution of signal and noise. Then we process wavelet coefficients with mixed threshold and do inverse transform to recover the data. The results demonstrate that translation invariant wavelet can not only remove the major part of Gaussian white noise, but also reserves high-frequency detailed information of FTG data. Obviously, translation invariant wavelet with mixed thresholding has preferable application effect in filtering FTG data.

This paper proposes a new semi-automatic inversion method for magnetic anomaly data interpretation that uses the combination of analytic signals of the anomaly at different heights to determine the depth and the structural index N of the sources. The new method utilizes analytic signals of the original anomaly at different height to effectively suppress the noise contained in the anomaly. Compared with the other high-order derivative calculation methods based on analytic signals, our method only computes first-order derivatives of the anomaly, which can be used to obtain more stable and accurate results. Tests on synthetic noise-free and noise-corrupted magnetic data indicate that the new method can estimate the depth and N efficiently. The technique is applied to a real measured magnetic anomaly in Southern Illinois caused by a known dike, and the result is in agreement with the drilling information and inversion results within acceptable calculation error.

Gravity data, which are critical in mineral, oil, and gas exploration, are obtained from the vertical component of the gravity field, while gravity gradient data are measured from changes in the gravity field in three directions. However, few studies have sought to improve exploration techniques by integrating gravity and gravity gradient data using inversion methods. In this study, we developed a new method to integrate gravity and gravity gradient data in a 3D density inversion using the non-linear conjugate gradient (NLCG) method and the minimum gradient support (MGS) functional to regularize the 3D inverse problem and to obtain a clear and accurate image of the anomalous body. The NLCG algorithm, which is suitable for solving large-scale nonlinear optimization problems and requires no memory storage, was compared to the Broyden–Fletcher–Goldfarb–Shanno (BFGS) quasi-Newton algorithm and the results indicated that the convergence rate of NLCG is slower, but that the storage requirement and computation time is lower. To counteract the decay in kernel function, we introduced a depth weighting function for anomalous bodies at the same depth, with information about anomalous body depth obtained from well log and seismic exploration data. For anomalous bodies at different depths, we introduced a spatial gradient weighting function to incorporate additional information obtained in the inversion. We concluded that the spatial gradient weighting function enhanced the spatial resolution of the recovered model. Furthermore, our results showed that including multiple components for inversion increased the resolution of the recovered model. We validated our model by applying our inversion method to survey data from Vinton salt dome, Louisiana, USA. The results showed good agreement with known geologic information; thus confirming the accuracy of this approach.

Geophysical exploration generates a very large amount of data, which require special techniques to process meaningfully. This paper presents a modification of the inversion method of probability tomography and a practical application of the method for the joint inversion with multiple gravity gradiometry tensors. The depth-weighting matrix is introduced to increase the vertical resolution. The problems associated with choosing tensors are discussed. We combine the high-performance computing techniques, Message Passing Interface with Compute Unified Device Architecture, for hybrid programming to build a faster parallel program. In the synthetic model tests, it is found that the joint inversion with multiple tensors is superior to the classical algorithm with a single tensor for delineating the boundary of the adjacent geological bodies. The hybrid parallel program has a speedup of far more than 100, which is higher than the program using one parallel technique alone; thus, the program could be used for large-scale data. The parallel algorithm is applied to real geophysical exploration data from Vinton Dome and we obtained a good density result. Our algorithm is demonstrated to be reliable and feasible.

Magnetic exploration plays a significant role in regional geological investigation and detection of underground geological bodies with magnetic anomaly. At the moment, aeromagnetic survey is widely applied for its high efficiency, low cost and less subject to terrain restrict. Magnetic compensation is a key step in pre-processing survey data and several methods have been used. In this paper, we would use partial least square method to complete aeromagnetic compensation. Partial least square regression is frequently used to find the fundamental relations between two matrices. It combines linear regression analysis, canonical correlation analysis and principal components analysis. It can be applied into data with multicollinearity among independent variables and the number of variables is larger than that of observations. Before compensation, we should have several pre-processing steps such as parallax correction, diurnal variations correction, geomagnetic field correction and high-frequency noise removal. This will provide us magnetic data with higher quality and make compensation process more accurate. We set synthetic aeromagnetic data with interference of aircraft’s maneuvers and used partial least square method to do compensation. From the results of simulation, we can see that the interference signal is reduced to a low degree and satisfied compensation effect is obtained. Partial least square regression is a stable and effective method in the application of aeromagnetic compensation.

We modify the classical preconditioned conjugate gradient method for full tensor gravity gradiometry data. The resulting parallelized algorithm is implemented on a cluster to achieve rapid density inversions for various scenarios, overcoming the problems of computation time and memory requirements caused by too many iterations. The proposed approach is mainly based on parallel programming using the Message Passing Interface, supplemented by Open Multi-Processing. Our implementation is efficient and scalable, enabling its use with large-scale data. We consider two synthetic models and real survey data from Vinton Dome, US, and demonstrate that our solutions are reliable and feasible.

Cytoplasmic male sterile (CMS) lines varied at pollen abortive phenotypes (PAP) have been used effectively for production of hybrid seeds in rice. To investigate the relationship between PAP of CMS lines and CMS-specific mitochondrial genes or structures in rice, CMS lines varied at PAP developed on 18 cytoplasmic sources were examined with seven PCR primers specific to three CMS-specific mitochondrial regions. The 18 CMS lines were classified into stained abortive (SA) and typical abortive (TA) types according to their PAP. Two CMS cytoplasms-specific PCR fragments, by which genotypes between the CMS lines and their maintainers were distinguished, were identified with primer LD29 or LD30. Furthermore, it was discovered that phenotypes of SA-CMS and TA-CMS were related to CMS-specific mitochondrial genes or structures, LD-orf310, atp6-orf79-like, and orf288-like structures. The results suggested that CMS phenotypes were mainly controlled by cytoplasmic genes, and it could be speculated that the SA-CMS phenotype was related to LD-orf310 and atp6-orf79-like structure, while TA-CMS phenotype was related to WA352.

In this study, Chinese upland rice cultivars including Handao297 and Handao502 were transformed with the anti-herbicide bar gene in order to achieve efficient weed control. PCR amplification, Southern blot analysis and field Basta resistance identification in early T0, T1, and late generation T6 and T11–T13 illustrated that the exogenous bar gene had been integrated into the genome of the upland rice varieties with stable expression in successive generations. Different transformants had a different gene copy numbers, which was not related to Basta resistance. Some of the transgenic lines showed gene silencing, whereas multiple copies of the bar gene were observed in other late generation transgenic lines. Basta resistance can thus be inherited stably among generations, and an optimal Basta concentration and selective pressure are suitable for resistance segregation and breeding of homozygous progenies with high resistance. After three generations of successive Basta resistance selection in 207 T0 plants, we obtained 555 T3 lines. Comprehensive identification and selection for Basta resistance, drought resistance, yield, and other agronomic traits in nine generations yielded two promising transgenic lines, HD297T-31 and HD297T-523. Although both varieties were resistant to 0.1 % Basta, HD297T-31 possessed high (100 %) resistance to Basta while HD297T-523 showed moderate (95 %) resistance. Moreover, during the reproductive stage, the stems, sheaths, leaves, and panicles of HD297T-31 were immune-highly resistant to highly-moderately resistant to 0.5 % Basta, whereas, they were highly resistant–moderately resistant to 1 % Basta. HD297T-523 was immune-highly resistant and immune-highly resistant to 0.5 and 1 % Basta respectively. The plant and stem percentage sensitive to 0.5 % Basta was lower than 1 and 3 % respectively. Since HD297T-31 showed isozygosity, it could be used as a new variety in production.

A derivative formula for interface inversion using gravity anomalies, combining the Parker–Oldenburg method for calculating and inverting gravity anomalies with Xu’s iteration method for continuing potential fields, leads to a convergent inversion algorithm and an optimally located density interface geometry. In this algorithm, no filtering or any other convergence control techniques are needed during iteration. The method readily iterates the variable depth of the gravity interface by means of upward continuation in a form equivalent to inversion iteration in the Fourier domain instead of the divergent, downward continuation term. This iteration algorithm not only efficiently solves the divergence problem in the inversion iteration procedure but also validly obtains an excellent result for the density interface. A numerical example is presented to illustrate perfect execution of this approach in gravity exploration, and a real geophysical example of inversion of the Moho depth by means of this approach using a set of measured gravity anomalies over the Qinghai–Tibet Plateau in China is offered.

Edge detection is a useful tool in the interpretation of potential field data, and the existing edge detection filters are almost functions of first-order horizontal and vertical derivatives. We propose step-edge detection filters to improve the resolution of edge detection results, which use the functions of different-order derivatives to accomplish the edge detection task. We demonstrate the proposed filters on synthetic potential field data, and the results show that the new methods can recognize the edges of the sources more precisely and clearly. We also discuss the application effect of different step-edge detection filters. Lastly, we apply the proposed filters to real potential field data, and the recognized edges of the stratigraphic markers are more precise and clear.

Many of the existing balanced edge detection filters of potential field data only use the feature that the vertical derivative is zero above the source edges to recognise the source edges. This will produce spurious edges in the interpretation of potential field data. In order to solve this disadvantage, a new format of the edge detection filter is presented, which produces maximum values only when the horizontal derivative is a maximum and the vertical derivative is zero, so the new filters will not produce spurious edges, and will provide more accurate results. The proposed filters are tested on synthetic potential field data. The recognised edges are shown to be consistent with the true edges, and do not produce additional edges. Moreover, the proposed filter suppresses the effect of noise, and displays the edges more clearly compared to previous edge detection filters. It is also applied to real magnetic data to obtain the horizontal locations of iron ore.

We developed a new method for interpretation of airborne gravity gradiometry data, based on cokriging inversion. The cokriging method that we evaluated minimized the theoretical estimation error variance by using auto- and crosscorrelations of several variables. It does not require iterations and can easily include complex a priori information. Moreover, the smoothing effects in the inverted density structure model can be reduced to a certain extent due to the anisotropy constrain in the covariance model. We compared the recovered models obtained by inverting the different combinations of gravity-gradient components to understand how different component combinations contributed to the resolution of the recovered model. The results indicated that including multiple components for inversion increased the resolution of the recovered density model and improved the structure delineation. Moreover, in the case in which the parameters of the variogram model are not well chosen, cokriging with multicomponent combinations can still correctly recover the geometry of the targeted sources. The survey data of the Vinton dome were considered as a case study. The results of the inversion were in good agreement with the known formation in the region. This supports the validity of our method.

Balanced edge detection filters can recognize the edges of the shallow and deep bodies simultaneously, and are commonly used in the edge detection of potential field data. In this paper, we present using the balanced edge detection filters to estimate source locations, and derive two linear equations based on the balanced edge detection filters that can estimate the locations of the source without any priori information about the nature (structural index) of the source. The proposed methods are demonstrated on synthetic gravity anomalies, and the inversion results show that the proposed methods can successfully estimate location parameters of the sources. I also apply the proposed methods to real magnetic data, and the inversion results estimated by the proposed methods are consistent with the results estimated by the other similar method.

Downward continuation is a useful tool in the processing of potential field data, which can effectively enhance weak anomalies and identify overlap anomalies, but we all know that the computation of downward continuation is unstable, and easily distorts the true feature of potential field data. Because the computation of upward continuation and horizontal derivatives is stable, we proposed using the combination of upward continuation and horizontal derivative to accomplish the downward continuation of potential field data. The proposed method is demonstrated on synthetic potential field data, and the results show that the proposed method can finish the downward continuation of the data stably and precisely, and the precision of the proposed method is higher than the traditional method. We also apply it to real potential field data, and the results show that the proposed method accomplishes the downward continuation of the real data stably.

The Greenwood frequency (GF) is influential in performance improvement for the coherent free space optical communications (CFSOC) system with a closed-loop adaptive optics (AO) unit. We analyze the impact of tilt and high-order aberrations on the mixing efficiency (ME) and bit-error-rate (BER) under different GF. The root-mean-square value (RMS) of the ME related to the RMS of the tilt aberrations, and the GF is derived to estimate the volatility of the ME. Furthermore, a numerical simulation is applied to verify the theoretical analysis, and an experimental correction system is designed with a double-stage fast-steering-mirror and a 97-element continuous surface deformable mirror. The conclusions of this paper provide a reference for designing the AO system for the CFSOC system.

Recent studies have shown that molecular control of inner floral organ identity appears to be largely conserved between monocots and dicots, but little is known regarding the molecular mechanism underlying development of the monocot outer floral organ, a unique floral structure in grasses. In this study, we report the cloning of the rice EXTRA GLUME1 (EG1) gene, a putative lipase gene that specifies empty-glume fate and floral meristem determinacy. In addition to affecting the identity and number of empty glumes, mutations in EG1 caused ectopic floral organs to be formed at each organ whorl or in extra ectopic whorls. Iterative glume-like structures or new floral organ primordia were formed in the presumptive region of the carpel, resulting in an indeterminate floral meristem. EG1 is expressed strongly in inflorescence primordia and weakly in developing floral primordia. We also found that the floral meristem and organ identity gene OsLHS1 showed altered expression with respect to both pattern and levels in the eg1 mutant, and is probably responsible for the pleiotropic floral defects in eg1. As a putative class III lipase that functionally differs from any known plant lipase, EG1 reveals a novel pathway that regulates rice empty-glume fate and spikelet development.

The presence of resistant selectable marker genes and other added DNAs such as the vector backbone sequence in transgenic plant might be an unpredictable hazard to the ecosystem as well as to human health, which have affected the safe assessment of transgenic plants seriously. Using minimal gene expression cassette (containing the promoter, coding region, and terminator) without vector backbone sequence for particle bombardment is the new trend of plant genetic transformation. In the present paper, we co-transformed the selectable marker bar gene cassette and non-selected cecropinB gene cassette into rice (Oryza sativa L.) by particle bombardment, then eliminated the selectable marker bar gene in R1 generation applying the hereditary segregation strategy and attained two safe transgenic plants only harboring cecropinB gene cassettes without any superfluous DNA. This is the fist report indicating that the combination of minimal gene cassettes transformation with the co-transformation and segregation strategy can generate selectable marker-free transgenic plants, which will promote the advancement in plant genetic engineering greatly.

Photosynthesis is the primary source ofdry matter production and grain yield inrice. Study on genetics of photosynthesisand related physiological characters isvery important to rice physiologicalbreeding. In this study, a double haploid(DH) population derived from anther cultureof ZYQ8/JX17, a typical indica and japonicahybrid was used as genetic material. Netphotosynthetic rate, chlorophyll content,stomatal resistance and transpiration rateof the parents and DH lines wereinvestigated in flourishing tilleringperiod. The quantitative trait loci (QTLs)for each trait were analyzed based on theconstructed molecular linkage map of thispopulation. A total of 8 QTLs forphotosynthesis and related physiologicalcharacters were detected. Two putative QTLsfor net photosynthetic rate (qNPR-4 andqNPR-6) were mapped on chromosome 4 and 6,respectively. Three QTLs (qCC-1, qCC-3 andqCC-8) for chlorophyll content weredetected on chromosome 1, 3 and 8,respectively. One QTL for stomatalresistance (qSR-4) was identified onchromosome 4. Two QTLs for transpirationrate (qTR-4 and qTR-7) were detected onchromosome 4 and 7, respectively. TheseQTLs should accelerate the process ofbreeding new rice varieties with higherphotosynthetic capacity and higher yield.

Gravity gradiometry has come to be a useful tool for both the mining and hydrocarbon exploration areas. Given borehole gravity has recently been used in mineral exploration with the advent of slim-hole gravimeters, it is logical to perform joint inversion to fully utilize the information in the newly acquired data. The inversions were carried out using cokriging that is a geostatistical method of estimation that minimizes the error variance by applying cross-correlation between several variables. The example presented demonstrates that the ability of the method to include the geological information and physical property from borehole measurements in the inversion. The results also show that the depth resolution of gravity gradient inversion can be significantly improved by including borehole data. Moreover, compared with inversion using only borehole data, incorporating gravity gradient data increases the lateral resolution of the recovered density model.

A double haploid population, derived from anther culture of F1 hybrid between a typicalindica and ajaponica (ZYQ8/JX17), has been used to investigate the low temperature germinability (LTG) at 15°C. The low temperature germinability of two parents was significantly different. In 6–11 d, the germination percentage of ZYQ8 was higher than that of JX17. In 12–16 d, the germination percentage of JX17 was higher than that of ZYQ8. The quantitative trait loci (QTLs) of every day for low temperature germinability have been mapped based on a molecular linkage map constructed from this population. In 8–11 d, qLTG-9 was identified in C397B-RZ617B on chromosome 9, the additive effect was positive, showing that the allele from JX17 could increase low temperature germinability. In 12–16 d, qLTG-4 was mapped between RG908 and CT563 on chromosome 4, the additive effect was negative, showing that the allele from ZYQ8 could increase low temperature germinability. These two QTLs were detected at different stages, showing the complexity of the mechanism of low temperature germinability.

Southern blot analysis indicated thatmtlD gene (encoding mannitol-1-phosphate dehydrogenase) andgutD gene (encoding glucitol-6-phosphate dehydrogenase) had been integrated into the rice genome mediated byAgrobacterium tumefaciens LBA4404(pBIGM). The expression of the above two genes in transgenic rice plants was demonstrated by Northern blot analysis and enzymatic activity assay. Analysis of sugar alcohol showed that transgenic rice plants could produce and accumulate mannitol and sorbitol. The salt tolerance of transgenic plants was much higher than that of their controls.

The herbicide resistant bar gene has been widely used as selectable marker genes in the study on plant genetic transformation. Owing to the integration of the gene into rice genome, transgenic rice was resistant to the herbicide Basta. Therefore, selection of transgenic plant and genetic analysis became easier. In the studies, bar gene was introduced as a genetic marker gene into rice restore line variety of two-line or three-line. Combined with conventional breeding method, the good herbicide resistant individual plant was derived as the new restore line for hybrid combination. After sprayed with Basta at seedling phase, the real hybrid rice that had herbicide resistance could grow normally, while the fake hybrid rice and weeds, having no bar gene, were killed by herbicide. The method described above helped rapidly to examine and improve the purity of hybrid rice.

Four transgenic rice lines TR 5, TR 6, Ming B and Jingyin 119 obtained via particle bombardment were used as transgene donors to create hybrids. The integration and expression stability of exotic bar and cecropin B gene in conventional hybriding transmission were investigated by Southern and Northern blotting analyses. The selection marker bar gene was transferred to all hybrids under selection of Basta herbicide. Loss or gain of small hybridization bands (no more than 2.0 kb) of bar gene occurred in some hybrids, but the difference in integration sites of bar gene copies did not influence their stable expression. The non-selection gene cecropin B was stably transferred from the four transgene donors to their resulting hybrids, but expression level was very different. Silencing of cecropin B gene occurred in some hybrids from TR 5, TR 6 and Ming B. In the transgene donor Jingyin 119 and all its resulting hybrids, cecropin B and bar gene were stably expressed. We concluded that the stability of transgene during crossbreeding transmission is mainly determined by the primary transgenic donors and may be affected by recombination.

Particle bombardment transformation using minimal gene cassette (containing the promoter, open reading frame and terminator) is the novel trend in plant genetic transformation, and its use helps to alleviate the undesirable effects of plasmid vector backbone sequences on transgenic plants. In the present article, studies related to the hereditary behavior of bar gene cassette in T(1) to T(3) generations of the transgenic rice (Oryza sativa L.) lines transformed by particle bombardment have been discussed. The selectable marker bar gene cassette that integrated with the rice genome had multiple copies and showed complex segregation behaviors including the presence of 'false homozygotes', with abnormal segregation ratios ranging from 35:1 to 144:1 (Basta-resistant: sensitive plants) in their progenies. In five out of ten original transgenic lines, bar gene can be stably transmitted as a dominant gene to self-pollinated T(2) progeny. The homozygotes were obtained in three transgenic lines in T(1) generation regardless of the multiple-copy integration patterns of bar gene. Southern blotting analysis showed that multiple copies of bar gene cassette were linked, which formed transgene arrays in the host rice genome. The authors also observed stable transmission of integration patterns of bar gene cassette, as obtained from Southern blotting analysis, in the regularly segregated transgenic rice lines and loss of gene in an irregularly segregated transgenic line. The segregation behavior varied among the transgenic progenies that exhibited similar Southern hybridization patterns of bar gene. On the basis of these results, the multiple-copy integration, gene lost, and gene expression interaction were the major reasons for the complex segregation behaviors of bar gene cassette in transgenic rice plants.

Gelatinization temperature (GT) is an important parameter for evaluating the cooking and eating quality of rice besides amylose content (AC). The inheritance of the genes affecting GT has been widely studied and is considered to be controlled by a major gene. Here, we report the map-based cloning of rice ALK that encodes the soluble starch synthase II (SSSII). Comparison between the DNA sequences from different rice varieties, together with the results obtained with digestion of the rice seeds in alkali solution, indicates that the base substitutions in coding sequence of ALK may cause the alteration in GT.