The APETALA2 (AP2) domain defines a large family of DNA binding proteins. It has been demonstrated that the AP2 proteins have important functions in the transcriptional regulation of a variety of biologic processes related to growth and development in various responses to drought and other abiotic stresses. In this essay, recent researches on the AP2 transcription factors, such as the molecular characterization, expression patterns in responses to drought and other abiotic stresses, the roles of ABA on drought responding which were mediated by AP2 transcription factors, transcription regulation mechanisms, and the roles of overexpression of AP2 transcription factor on plant drought tolerance, etc. have been overviewed. Deepening the understanding of signaling and the corresponding transduction pathways that are initiated via drought stress stimuli will play crucial roles for providing the theoretical basis for variety breeding with promising drought tolerance in the future.

H⁺ is a root secretion that affects P acquisition and P-use efficiency (PUE) under deficient phosphorus in maize. The secretion of H⁺, difference value of H⁺ between deficient and normal phosphorus (DH), and relative H⁺ (RH) as well as the quantitative trait loci (QTLs) associated with these traits were determined for a F_2:3 population derived from the cross of two contrasting maize (BoldItalic L.) genotypes, 082 and Ye107. By using composite interval mapping (CIM), a total of 14, 8, and 9 distinct QTLs were identified for H⁺, DH, and RH, respectively. Most loci of QTLs for traits H⁺, DH, and RH had different cross environments. It showed that H⁺ secretion possessed an environment-sensitive and multi-gene nature. The gene × environment interaction was actually reflected by H⁺ secretion. One region for QTL of trait H⁺ was detected at the interval of bnlg2228-bnlg100 (bin 1.08) on chromosome 1. Coincident QTLs in the important genomic region reflected the cross phosphorus levels, different cross growth stages, and two different cross environments. The QTL explained 10% to 14% total phenotypic variance of H⁺. Therefore, the above segment (bnlg2228-bnlg100) (bin 1.08) identified on chromosome 1 may be used in the future for MAS to improve the phosphorus efficiency in maize.

The effects of soil drought on soluble protein content and protective enzyme system of cotton leaves at different positions were studied in the transgenic cotton cultivar, Lumianyan28. The results indicated that the soluble protein content in main stem leaves and in middle-fruit branch leaves under drought treatment were higher than that of CK, the normal soil water management treatment. Lower fruit branch leaves under drought treatment had higher protein and enzyme levels than CK treatments. From June 25 to July 22, the activity of superoxide dismutase (SOD) in main stem leaves under drought treatment was lower than that of CK. Other time periods had varying results. The peroxidase (POD) activity in main stem leaves and in fruit branch leaves was lower at early stage and then higher at late stage, showing a trend of descending first, and then ascending obviously under the drought condition. The catalase (CAT) activity showed an increase-decrease trend, higher in main stem leaves under drought treatment than that of CK. However, it was opposite in the lower fruit branch leaves, and there were no significant differences between the two CAT treatments in the middle branch leaves. It is suggested that the soluble protein and cellular protection enzymes, such as superoxide dismutase, peroxidase activity, and catalase in main stem leaves and fruit branching leaves play important physiological functions in the early growth stage under drought stress.

The acclimation of plants to cold, salt and dehydration is involved in the action of the transcription factor (CBF) cold-response pathway. In this paper, nineteen rice CBF genes, including seven previously released and twelve unpublished novels, were identified and characterized. The multi-members of rice CBFs (OsCBF1 to OsCBF12) were divergent at the nucleotide and amino acid level. Expression analysis shows that five novel rice CBF genes (OsCBF1, OsCBF2, OsCBF3, OsCBF8, and OsCBF9) responded to short-term (1 h or 3 h) stresses of low temperature, salt stress and dehydration. The transcripts of OsCBF2, OsCBF8 and OsCBF9 in the roots were rapidly elevated when the plants were exposed to low temperatures, suggesting that they were possibly involved in low temperature responses in rice plants. Meanwhile, the expression level of OsCBF2 in leaves was enhanced when exposed to salt stress of 1–3 h, implying that OsCBF2 functioned as a transduction component in the salt stress signal cascade. Various expression patterns in OsCBF1, OsCBF2, OsCBF3, OsCBF8, and OsCBF9 under low temperature, salt and drought conditions, together with the different expression patterns between roots and leaves for each of these indicated that every rice CBF gene has unique and non-redundant functions in the response to the abiotic stresses.

A sample of soybean accessions (Glycine max (L.) Merr.) from Huanghe Huaihe Haihe and Middle Lower Changjiang Valleys in China was used to identify their tolerance to rhizo-spheric stresses, including drought, aluminum toxin and low phosphorus. A total of 15 accessions highly tolerant to at least one of the abiotic stresses were screened out. The correlation between drought tolerance and the relative values of total root length, root volume and dry root weight (relative to dry plant weight) were all significant at 0.01 level, respectively. So did for the correlation between aluminum toxin tolerance and the stress to non-stress ratios of the number of lateral roots, tap root length, total root length, root volume and dry root weight. The inheritance study on the above three root traits related to drought tolerance under segregation analysis indicated that between the two parents of the recombinant inbred line (RIL) population of (Kefeng 1?Nannong 1138-2), the relative values of dry root weight, total root length and root volume were controlled by two major genes plus polygenes with their major gene heritability values 62.26% 91.81% and polygene heritability values 2.99% 24.75%, respectively, and for the latter two traits, the two major genes linked together with recombination value 4.30% and 1.93%, respectively. The inheritance study on the five root traits related to aluminum toxin tolerance revealed that between the two parents of the recombinant inbred line RIL) population of (Bogao?NG94-156), the stress to non-stress ratios of lateral root number, tap root length, total root length and dry root weight were controlled by three major genes plus polygenes with their major gene heritability values 80.22% 91.81% and polygene heritability values 3.52% 11.39%, while the stress to non-stress ratio of root volume was controlled by three major genes with their major gene heritability value 93.44%. The (Kefeng 1?Nannong 1138-2) RIL population was also used for mapping QTLs of relative dry root weight, total root length and root volume related to drought tolerance. Five, three and five QTLs located on Linkage group N6-C2, N8-D1b+W, N11-E and N18-K for each of the three traits, respectively, were identified. Each of the traits appeared to have one locus (Dw1, Rl1, Rv1) with relatively large effect in comparison with their other loci, and the three loci in above parentheses were located in the same region STAS8_3T-STAS8_6T on N6-C2 with a same distance to the flanking markers. Thus, Dw1, Rl1, and Rv1 even might be a same locus and performed as pleiotropic of a same gene. The results between segregation analysis and QTL mapping appeared relatively consistent, therefore could be used for verification each other.

Seventy-one glandless cotton germplasm resources were firstly evaluated genetically by using nine agronomic traits, 33 simple sequence repeat (SSR) primers and ten amplified fragment length polymorphism (AFLP) primer combinations. Principal component analysis (PCA) of the agronomic traits showed that the first six principal components (PCs) explained a total of 86.352% of the phenotypic variation. A total of 329 alleles were amplified for 33 SSR primers, and 232 polymorphic bands in a total of 389 bands were obtained by using ten AFLP primer combinations. The average polymorphic information content (PIC) value was 0.80 and 0.18 for SSR primers and AFLP primer combinations, respectively. The DIST (average taxonomic distance) and DICE (Nei and Li’s pairwise distance) coefficients ranged from 0.373 to 3.164 and 0.786 to 0.948, respectively, for agronomic traits and SSR&AFLP data based on UPGMA analysis. This suggested that there was a higher diversity in the evaluated population for both agronomic traits and molecular markers. The Mantel’s test showed that the correlation between the dendrograms based on agronomic traits and SSR&AFLP data was non-significant.

The allelopathic influence of aqueous extracts of Thymus kotschyanus on Bromus tomentellus and Trifolium repens germination (%), germination speed, and seedling growth (length, fresh and dry weight) was examined. It was noted that aqueous extracts had a considerable inhibitory effect on target plant germination, and the effect at 50%, 75%, and 100% concentration was found to be significantly higher than that at lower concentrations (5% and 25%) and control treatment (distilled water). Seedling length in addition to fresh and dry weights was also reduced significantly over control. The inhibitory effect was increased as the extract concentration was increased. B. tomentellus showed a higher sensitivity against T. kotschyanus in allelopathic effects compared to T. repens, which indicates that B. tomentellus planted in rangelands with leaf litter of T. kotschyanus will be adversely affected in terms of its germination, growth, and ultimately low forage production.

A RIL population from two Australian wheats, Lang and CSCR6, was employed to evaluate the genetic variation and to detect QTL associated with dough rheological characters based on DArT and SSR markers and two environmental experiments. It was showed that the higher variation existed in the RIL for dough rheological characters, and so did much more abundant selection potentials that lacked in Chinese current commercial varieties. Nine additive QTLs for dough rheological characters were identified. Of which those for water absorption (WA) were located on chromosome 2A and 5A, stability time (ST) on 4B and 1B, breaking time (BT) on 1B, degree of softening (DS) on 1B, band width (BW) on 2B (two loci), evaluation value (EV) on 1B. And seven epistatic QTLs were screened out, and non-significant variance was found for the interaction between these epistatic QTLs and the environment. Correlation analysis indicated that there was a significantly positive relation between WA and development time (DT), and EV, whereas negatively related to BW. A significantly positive relation existed between DT, ST, BT and EV each other. They were negatively related to mixing tolerance index (MTI) and degree of softening (DS), both had a markedly positive relation.

Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Currently, dozens of rice resistance (R) genes against specific races of the blast fungus have been described. Among them, ten were molecularly characterized and some were widely used for breeding for genetic resistance. The Pi-ta gene was one of the best characterized rice R genes. Following the elucidation of its molecular structure, interaction, distribution, and evolution, user friendly DNA markers were developed from portions of the cloned genes to facilitate the incorporations of the Pi-ta mediated resistance into improved rice varieties using marker assisted selection (MAS). However, rice blast is still a major threat for stable rice production because of race change mutations occurring in rice fields, which often overcome added resistance based on single R genes, and these virulent races of M. oryzae pose a continued challenge for blast control. For sheath blight, progress has been made on the exploration of novel sources of resistance from wild rice relatives and indica rice cultivars. A major quantitative trait locus (QTL), named qSB9-2, was recently verified in several mapping populations with different phenotyping methods, including greenhouse methods. The ability to identify qSB9-2 using greenhouse methods should accelerate the efforts on the qSB9-2 fine mapping and positional cloning.

It is necessary to find out the genetic characteristics of malic acid in the course of apple genomic research and breeding. In this study, the SSR marker linked to the acid/low-acid trait in apple fruit was identified from 140 SSR primer pairs, using 91 F₁ population hybrids from the intra-specific cross between apple cultivar ‘Dongguang’ and ‘Fuji’ as the experimental materials. Of 140 SSR primer pairs, only primer SDY085 produced a polymorphic band linked to acid trait, and the linkage distance was 8.89 cM. Also, the titrated acid and malic acid in different developmental stages were determined. The SSR marker analysis, coupled with the change of the total acid and malic acid contents, revealed that the acid/low-acid trait was governed by a major gene and acid trait was completely dominant.

Malate dehydrogenase (MDH) ubiquitously exists in animals, plants and microoganisms, and catalyzes the interconversion from oxaloacetate to malate. Cytosolic NAD-dependent MDH gene (cyMDH) encodes a key enzyme crucial for malic acid synthesis in the cytosol which has not been extensively characterized in plants. In this study, a full-length cDNA of cyMDH was isolated from apple fruits with RT-PCR as well as 3′ and 5′ rapid amplification of cDNA ends, and designated as Mal-cyMDH (GenBank accession No. DQ221207). It contained a 996-bp ORF and its sequence analysis shows a high similarity to other plant cyMDHs. Phylogenetic analysis indicated that almost all the cyMDHs could be clustered into the same group and it was likely to represent the original MDH. A roughly 37-kDa fused protein was obtained by the recombinant prokaryotic expression and its enzyme activity assay showed that it mainly catalyzed oxaloacetate to malate. It was also discovered that the enzyme activity of cyMDH exhibited remarkable difference between the high- and low-acid apple germplasm.

To counter the actual problems of forage shortage and low quality existing in the agriculture–animal husbandry ecotone in North China, a research was conducted to study the effects of plastic-film mulching and nitrogen application on the production of forage-oriented maize with the aim of producing water-saving forage with high-yield and good quality. Field experiments combined with laboratory experimental estimation and analysis was adopted. Plastic-film mulching increased the dry biomass of forage-oriented maize by 23.8% with effectively improving the maize’s nitrogen absorption so that the apparent utilization ratio and output-input ratio of nitrogen were enhanced. The content of crude protein in maize plant was increased and thus, forage nutritive quality was improved. Plastic-film mulching remodeled the maize field water consumption scheduling pattern and increased the water use efficiency by over 10%. Nitrogen application to forage-oriented maize co-improved the biomass and the nutritive quality with the nutritive matter (percentage and yield) several times of the biomass. Nitrogen application increased maize biomass production by 36.1%–39.5% and it increased the contents of crude protein and crude fat in maize plant by 109% and 145%, respectively. The yields of the two nutritive matters increased by 160% and 210%. Nitrogen application at the rate of about 200 kg·hm^-2 to the uncovered field and the rate less than 300 kg·hm^-2 to the field with film mulching were considered as the most proper rates to guarantee high yield and good quality of forage-oriented maize and were the rates to keep the available nitrogen balanced in the soil. Plastic-film mulching and nitrogen fertilizer application to forage-oriented maize was an effective way of producing forage with high yield and good quality, relieving the shortage of animal forage and accelerating ecological recovery and economic development in this ecotone in North China.

Fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) were applied to somatic chromosome preparations of Oryza sativa, O. officinalis/ and O. meyeriana with labeled probes of C₀t-1 DNA and genomic DNA from cultivated rice. The coverage percentage (%) and size (Mb) of C₀t-1 DNA in O. sativa, O. officinalis and O. meyeriana were 47.1±0.16, 38.61±0.13, 44.38±0.13 and 212.33±1.21, 269.42±0.89, 532.56±1.68, respectively. The coverage percentage and size of probe signals with gen omic DNA from O. sativa in O. officinalis and O. meyeriana were 91.0%, 93.6% and 634 Mb, 1 123 Mb respectively, in which there were 365 and 591 Mb in O. officinalis and O. meyeriana which came from O. sativa genomic DNA not from repetitive sequences of O. sativa, and the uncovered genome size in O. officinalis and O. meyeriana was 64 and 78 Mb, respectively. In addition, karyotype analysis was conducted based on the signal bands of C₀t-1 DNA in O. sativa, O. officinalis and O. meyeriana. The results showed that highly and moderately repetitive sequences in Oryza genus were conserved as the functional genes during the evolution process. The repetitive sequence reduplication might be one of the important causes of genome enlargement in O. officinalis and O. meyeriana; the O. officinalis genome enlarged more slowly compared with O. meyeriana. Based on the above results, it is concluded that O. officinalis and O. meyeriana formed by reduplication, rearrangement and gene selective loss during the evolution process.

The essential oil from the leaves of yacon grown in China was isolated by hydrodistillation and distillation-extraction. Chemical constituents of the essential oil were separated and identified by means of gas chromatography/mass spectrometry (GC/MS) for the first time, and the relative content of each constituent was determined by area normalization. Twenty-one chemical constituents were identified, and their amounts accounted for 96.2% of the total composition. The main components of the essential oil were β-phellandrene (26.3%), β-cubebene (17.7%), β-caryophyllene (14.0%) and β-bourbonene (10.2%). Therefore, in the volatile oil from the leaves of yacon, sesquiterpenes are major compounds, accounting for 52.2%.

Effects of salicylic acid (SA), ultraviolet radiation (UV-B and UV-C) on the trans-resveratrol (Res) inducement of the skin of harvested grape berries were studied with three grape cultivars Takasuma, Tano Red and Carigane. Split plot design tests were adopted to compare the effects of UV-B and UV-C radiation on Res inducement of different cultivars. Results showed that spraying 100 mg·L^-1 SA markedly enhanced Res contents in the skins of harvested berries for the three selected cultivars. However, the effect of SA varied with the cultivars, and Res inducement by SA was more effective to Tano Red than Takasuma and Carigane. UV-B or UV-C irradiation significantly increased Res contents in grape skins and UV-C was more effective than UV-B. The effects of UV types and dosages on Res inducement depended upon cultivars. In the range of 0–3.6 kJ·m^-2, the Res contents in the skins of the three grape cultivars were enhanced along with the increase of dosages of UV-B and UV-C.

The wheat × maize system is one of the most effective ways to produce haploids in wheat. Whether and how it could be successfully applied in practical breeding mostly depends upon the efficiency of haploid embryo production. To perfect the protocols of haploid embryo induction, the efficiency of haploid embryo production between in vitro culture of cut plant and intact plant growth for hybrid spikes with two F₁ wheat hybrids and two maize varieties was compared. Effects of different cutting plant times and formulas of nutrient solutions for cut plant culture on haploid embryo formation were also studied. Results indicated that the embryo rate of in vitro culture was 3.29 times that of intact plant growth, with the figures of 31.6% vs 9.6%, respectively. The optimal time for cut plant culture was 24 h after pollination. Formulas of nutrient solutions significantly affected the efficiency of haploid embryo induction. With an embryo rate of 0–35.5%, adding calcium phosphate in the culture solution at 3 g·L^-1 could raise the caryopsis and embryo rates. According to this study, the best medium for cut plant culture was: 100 mgL^-1 2,4-D + 40 gL^-1 sucrose + 10 mgL^-1 silver nitrate + 8 mLL^-1 sulfurous acid + 3 gL^-1 calcium phosphate, with which a caryopsis rate of 95% and an embryo rate of about 30% could be obtained.

Under abiotic stress, the calcium-dependent protein kinases (CDPKs) in plant species are activated by the fluctuated Ca²⁺ levels in cytoplasm and thereby provide a mechanism to decode calcium signals. In this paper, twenty-two rice CDPK genes were identified based on scanning the rice genome released in National Center for Biotechnology Information (NCBI). It was found that there were dramatic differences on the DNA length, cDNA length, open reading frame (ORF) and the translated amino acids among the rice CDPK genes, with the highest diversity on the DNA length. Calculations of the exon/intron numbers and the lengths of exon and intron revealed that all of the rice CDPK genes had the longest exon at the position of exon 1, but the lengths of introns in different genes showed different patterns. The gene structure and phylogenetic analysis indicated that the rice CDPK genes had derived at least from two diffe rent ancestors during the evolution. The expression analysis elucidated that the rice CDPK genes showed different patterns under normal growth (CK) and salt stress condition, including constitutively expression (OsCDPK4, OsCDPK18, OsCDPK19 and OsCDPK24), down- or up-regulated in roots by salt stress (OsCDPK10 and OsCDPK16), up-regulated in leaves by salt stress (OsCDPK6, OsCDPK20 and OsCDPK13), and no detected transcripts under CK and salt stress con dition. Therefore, the members of rice CDPK gene family should be evolutionally divergent and several members could play an important role in transducing the signal of salt stress.

The undisturbed regions along the Qinghai-Tibet Highway crossing the natural zones of montane desert, alpine meadow-steppe, and montane shrub-coniferous forest were chosen as the study areas. Soil samples were collected at 23 sites and the relations between the influencing factors and distribution of soil organic carbon (SOC) content were studied. The results indicated that the order of SOC content for the whole soil profile with different vegetations and in the horizontal direction was shown as below: forest > shrub > meadow > steppe > desert. All the SOC contents of the top 10 cm soil layers of forest, shrub and meadow vegetations, as well as that of the top 20 cm soil layers in steppe, in the vertical direction, were higher than those of corresponding lower soil layers. However, the SOC content in the desert soil was in accordance. The grey correlative analysis between the climatic factors and SOC content in the top soil show that precipitation was the dominant climatic factor affecting the distribution of SOC in the Tibetan Plateau transect. The influence of precipitation on the horizontal distribution of SOC decreased with the increase of precipitation in the horizontal direction. The vertical distribution of SOC along the soil profile was greatly affected by precipitation or the soil clay content in top soil layers, and was clearly influenced by soil silt content or sand content in lower soil layers, as well. The influences of both soil bulk density and soil pH on the vertical distribution of SOC along the soil profile gradually declined. The plant biomass was the most important biotic factors affecting the distribution of the SOC.

The strains capable of resistance against Verticillium dahliae Kleb were isolated and screened from the soils of cotton fields from several different provinces in China. A strain, coded DM-54, with a rather high antagonistic activity was obtained. Its morphological characteristics, physiological and biochemical properties and a 16 S rDNA sequence of this strain were further studied. The DM-54 strain was finally identified as a kind of Bacillusamyloliquefacien. Through a single factor experiment and an orthogonal experiment, the optimal shaking flask fermentation condition of strain DM-54 was found to be: media composed of 5% dextrin, 3% soy peptone, 0.02% MgSO₄, 0.01% CaCl₂, initial pH 7.0 and 10% inoculum volume, media volume 30/250 (mL/mL), fermentation temperature at 32oC, rotating speed 200 r?min^-1, fermentation time of 48 h. Its antagonistic activity was distinguished to be elevated, at about 39.9%. Our research offers an effective means for the massive production of antagonistic proteins.

To inhibit the browning process in fruits of Yali pear, in this paper, antisense gene techniques were used to reduce the expression of BoldItalic gene. A cDNA fragment of 450 bp, which is located at the 3′ terminal of the polyphenol oxidase (BoldItalic) gene, was amplified from Yali pear using the RT-PCR method, then the antisense expression vector was constructed by inserting the fragment of the Yali pear BoldItalic gene between the CaMV promoter and NOS terminator of the expression vector pBI121 in a reverse orientation. After that, with the agrobacterium-mediated method, the BoldItalic antisense gene was transformed into Yali pear shoots. Northern blot analysis and enzyme activity assay showed that the PPO activities in the transgenic Yali pear shoots were significantly decreased, compared with the non-transformed Yali pear shoots. This lays a good foundation for breeding new varieties of pears with browning resistance in the future.

The adaptation of plants to stressed environments depends greatly upon the metabolic level of antioxidant systems within their bodies. Among the enzymatic antioxidant systems, the AsA-GSH cycle occupies a vital place and has become a hot research field in recent years. The AsA-GSH cycle can directly scavenge H₂O₂ produced in plants on one hand, and the antioxidants AsA and GSH produced in the cycle can also scavenge other species of active oxygen by means of additional pathways on the other hand. Environmental conditions and exogenous formulations can alter the oxidative and reductive status in plants and mediate the metabolic level of the AsA-GSH cycle within a certain range, thus regulating the resistance of plants to stresses. The present paper reviews the advances in research on the AsA-GSH cycle with respect to horticultural crops, so as to provide some beneficial reference for further studies.

In this study, analyses of phenotypic characters, SSR molecular markers and pedigrees were done to study the genetic diversity in 186 maize hybrids that were tested in regional trials in Sichuan and Southwest China. The results showed that there were differences in the variation coefficients of different characteristics, but all of the variation coefficients changed within a narrow range. Sixty pairs of simple sequence repeat (SSR) primer distributed on the ten chromosomes of maize produced stable amplified bands and 608 alleles were detected among the hybrids. The average number of alleles per locus was 10.1 ranging from 3 to 23. The values of polymorphism information content (PIC) for each SSR locus varied from 0.5179 to 0.9256 with an average of 0.7826. The genetic similarities of SSR marker pattern among the 186 hybrids ranged from 0.6067 to 0.9162, with an average of 0.7722. There were 16499 pairs of genetic similarity, in which 96.9% were 0.70000 to 0.9256. The cluster analysis showed that the hybrids could be classified into ten clusters, with 88.2% of the hybrids included in Cluster 4, Cluster 8 and Cluster 10. The analysis of pedigree sources of 51 hybrids showed that 36 hybrids had close genetic relationships with the hybrids developed by the Pioneer Company in the late 1980s and early 1990s in the United States, such as Y78599, Y7865 and Y78698, accounting for 70.58%. Meanwhile, 13 hybrids had close genetic relationships with Y78599, accounting for 8.66%. The genetic similarities of SSR marker pattern among the 51 hybrids ranged from 0.66192 to 0.8799, with an average of 0.7686. There were 1196 pairs of genetic similarity ranged between 0.7000 to 0.8796, accounting for 93.80% of all the genetic similarity pairs. The cluster analysis showed that 88.2% of the 51 hybrids were in Cluster 4, Cluster 8 and Cluster 10, which indicated that similarity was high and genetic diversity narrow among the 186 hybrids. This showed that it is necessary to broaden the genetic basis of breeding germplasm in maize.

The present study examined the influence of the different fertilization on the dynamic of soil microbial biomass carbon (SMBC) of red soil in tea gardens. The results showed that straw mulching, intercropping, chemical fertilizer could all improve the amount of the soil microbial biomass C. The annual variation of microbial biomass C showed the tendency of “low–high–low–high”, and the influences were variable with the time. For the annual average of soil microbial biomass C, Treatment 1(T₁) (straw mulching + 100% organic manure), Treatment 2 (T₂) (straw mulching + 75% organic manure + 25% fertilizer), Treatment 3 (T₃) (straw mulching + 50% organic manure + 50% fertilizer), Treatment 4 (T₄) (straw mulching + 25% organic manure + 75% fertilizer), Treatment 5 (T₅) (100% fertilizer),Treatment 6 (T₆) (intercropping white clover) were 17.05%, 32.38%, 32.05%, 24.30%, 26.23%, 24.63% higher, respectively, than CK, and the differences among all the treatments were significant (P < 0.05). The correlation of the SMBC with the active organic matter, the total nitrogen, the microbial biomass N, the microbial biomass P were remarkable, but no significant correlation was found with available nitrogen, total phosphorus, total potassium and moisture. Compared with other treatments, those mixed with organic matter and chemical fertilizer were more advantageous to enhance the soil fertility.

A molecular map of melon (Cucumis melo L.) was constructed with SRAP (Sequence-Related Amplified Polymorphism) markers using a population consisting of 114 F₂ individuals derived from the cross of 4G21 (C. melo var. chinensis) and 3A832 (C. melo var. saccherinus). Twenty-nine primer pairs were used and 187 polymorphic loci were produced. The map consists of 12 linkage groups that include 152 genetic markers and cover 2077.1 cM with an average genetic distance of 13.67 cM. Every linkage group has 6–32 genetic markers with average genetic distance of 9.72–19.19 cM. The length of linkage group is 85.3–496.1 cM.

To elucidate the inheritance of seed coat color in Brassica juncea, Sichuan Yellow inbred (PY) was crossed with the Ziyejie inbred, and their F₁, F₂ and BC₁ and BC₂ progenies, derived from backcrossing to PY, were phenotyped for seed coat color. Results showed that the yellow seed coat was controlled by two independent recessive loci. Seven brown-seeded near-isogenic lines were developed by successive backcrosses to PY and by selfing. One of the BC₆F₂ populations segregated for a single locus controlling seed coat color was used for mapping. Using the 88 primer pairs from sequence-related amplified polymorphism and the 500 random primers, two markers were found to be linked to the gene for brown seed coat, which were designated as SCM57 and SCM1078. The crossover between these markers and the brown seed coat loci was 2.35% and 7.06%, respectively. A sequence characterized amplified region (SCAR) marker according to Negi et al. (2000), designated as SZ1-331, was found to be linked to the gene for brown seed coat, with a cross-over estimate of 2.35%. The markers were located on the same side of the brown seed coat loci and 2.41, 7.51 and 2.41 cM away from the brown seed coat locus. The seven brown-seeded near-isogenic lines were classified into two groups by three DNA markers. They were located at the same linkage group of the marker RA2-A11 previously published by Padmaja et al. (2005).

This article discusses a range of studies on starch changes in tobacco leaves during flue-curing. Important effects resulting from using different flue-curing equipment and techniques on starch content are presented. It concludes that future researches should be focused on the structure and physico-chemical properties of tobacco starch during the curing process.

Tea is the most popular non-alcoholic and healthy beverage worldwide. Tea production contributes greatly to the economy and the job opportunities for many countries in Asia and Africa. Meanwhile, the germplasm of tea, with a huge potential for the future of the whole tea industry, is presently one of the most valuable and fundamental materials for tea breeding and tea biotechnology. DNA molecular markers have been proven to be robust and valuable approaches in the studies of genetic diversity and variation, molecular identification, molecular phylogenetics, genetic stability and integrity of tea germplasm, and the genetic linkage map for breeding of tea. In this paper, a brief prospect on the molecular marker studies of tea has been summarized. The purpose is to provide an effective way for undertaking a massive tea germplasm appraisal and evaluation, to develop new applicable and cheap DNA markers, to establish a high density genetic linkage map and analyze the agronomically important QTLs, and finally, to facilitate the marker assisted early selection and shorten breeding procedures in tea.

In the long run, whether the use of chemical fertilizers could be reduced and soil fertility could be maintained through rice–fish coculture is less well known. At the pilot site of the rice–fish coculture system, which is one of the five “globally important agricultural heritage systems” (GIAHS), we conducted a 4-year study to compare fertilizer use, rice yield, and soil fertility in rice–fish coculture and rice monoculture. Based on the survey data from 21 villages, rice yield did not differ between rice monoculture and rice–fish coculture, but less chemical fertilizers were used in rice–fish coculture than in rice monoculture. Survey data from 145 farms also showed that rice–fish coculture farms with high input of feed for fish used less chemical fertilizers for rice production than farms with low input of feed for fish. In the 4-year field experiment, although less fertilizer was used in rice–fish coculture, rice yield, soil organic matter, soil total nitrogen, and soluble phosphorus did not differ between rice–fish coculture and rice monoculture. Our results suggest that rice–fish coculture can reduce chemical fertilizers application, enhance land productivity, and maintain soil fertility. Our results also suggest that rice–fish coculture could reduce the risk of non-point source pollution by reducing the input of chemical fertilizers.

The development of genomics and bioinformatics offers new tools for comparative gene mapping. In this paper, an integrated QTL map for sugarcane mosaic virus (SCMV) resistance in maize was constructed by compiling a total of 81 QTL loci available, using the Genetic Map IBM2 2005 Neighbors as reference. These 81 QTL loci were scattered on 7 chromosomes of maize, and most of them were clustered on chromosomes 3 and 6. By using the method of meta-analysis, we identified one “consensus QTL” on chromosome 3 covering a genetic distance of 6.44 cM, and two on chromosome 6 covering genetic distances of 16 cM and 27.48 cM, respectively. Four positional candidate resistant genes were identified within the “consensus QTL” on chromosome 3 via the strategy of comparative genomics. These results suggest that application of a combination of meta-analysis within a species with sequence homology comparison in a related model plant is an efficient approach to identify the major QTL and its candidate gene(s) for the target traits. The results of this study provide useful information for identifying and cloning the major gene(s) conferring resistance to SCMV in maize.

The efficient acceptors for maize transgenic engineering are currently insufficient in China. Seed production by male sterility is the best method for advancing the authenticity of maize hybrid. Maize inbred line 18-599 (white) is an antivirus high-quality maize inbred line in China, which has been used for lots of maize hybrid cultivars. The establishment of high efficiency transgenic acceptors is necessary for advancing the transgenic efficiency in maize transformation work. In this study, the efficient transgenic acceptors were optimized and established. 18-599 (white) was studied in state, types of culture mediums, times of callus regeneration and concentration of the screening reagent, Basta. The results showed that N6-4 medium was the best in 8 types of mediums for the immature embryo of 18-599 (white), 1.6 mm length was the feasible length of immature embryos for tissue culture in establishing the transgenic acceptor system, and it was within 5 times for suitable callus subculture. With the optimized transgenic acceptors, barnase gene was translated successfully into 18-599 (white) by a particle gun using bar as a marker gene. Basta was used as the screening reagent, its lethal concentration was 8 mg·L^-1 and its working concentration for screening was 6, 8 and 6 mg·L^-1 in 3 turns for callus regeneration, respectively. In this work, a transgenic plant with male sterility was obtained through molecule detection and observation in the field. The result has an important significance for the creation of new male sterility inbred lines in maize in the future.