千粒重(TGW)、穗粒数(GNS)和穗粒重(GWS)是小麦产量的重要组成部分。为了解析其遗传学基础，我们构建了一个由8762/Keyi5214衍生的198个系组成的DH群体，利用基因芯片对该DH群体进行基因型鉴定，并将产量相关性状千粒重、穗粒数和穗粒重表型整合并进行QTL定位。最后，我们共获得18,942个多态性SNP标记，并鉴定出41个与这些性状相关的关键QTL。我们在染色体2D和6A上鉴定出三个稳定的千粒重QTL (QTgw-2D.3, QTgw-2D.4, QTgw-6A.1)，其增效等位基因均来自亲本8762，解释了4.81%-18.67%的表型变异。在染色体3D、5B、5D和6A上鉴定出5个稳定的穗粒数QTL，其中QGns-5D.1来自亲本8762，其余4个来自亲本Keyi5214的QTL解释了5.89-7.08%的表型变异。此外，还发现了一个稳定的小麦穗粒重遗传位点QGws-4A.3，该位点来自亲本8762，可解释6.08-6.14%的表型变异。为了应用鉴定到的QTL，我们为四个重要的QTL (Tgw2D.3-2, Tgw2D.4-1, Tgw6A.1 和 Gns3D.1)开发了STARP标记。本研究结果可为后期小麦千粒重、穗粒数和单穗重相关基因的鉴定和克隆奠定基础。

本研究利用华北平原2年的田间定位试验，研究了条带深旋耕和控释尿素耦合对玉米产量和氮素利用效率的影响，及其氮素积累和产量形成的相关生理过程。与常规旋耕（RT）和免耕（NT）比，由于条带深旋耕（ST）使0-40 cm土层的土壤容重分别降低了10.5%和13.7%，从而显著提高了20-40 cm土层的土壤含水量和土壤矿质氮含量。与普通尿素（CU）比，控释尿素（CR）使开花期和成熟期0-40 cm土层的土壤矿质氮含量分别提高了12.4%和10.3%。因此，ST和CR显著提高了玉米根长和氮素总积累量，从而促进了叶片面积和干物质积累（特别是花后干物质积累）的增加，最终提高了玉米千粒重。ST处理产量比RT和NT处理分别提高了8.3%和11.0%，CR处理产量比CU处理提高8.9%。由于ST和CR耦合处理产量和氮素积累量的增加，显著提高了玉米氮素利用效率。综述可知，ST与CR结合可以通过改善土壤理化特性和氮素供应，进一步提高玉米产量和氮素利用效率，该措施可作为华北平原以及世界上其他类似地区的促进玉米可持续生产发展的有效措施。

本研究调查了香味和抗寒无核品种选育中不同浓度的多效唑及胚采集时期对胚形成、萌发和成苗率的影响。结果显示，不同浓度的多效唑对不同葡萄品种子房和胚的发育影响不一致。红无籽露×北冰红和昆香无核×泰山-2组合在1.5 mg L^-1多效唑处理下胚形成率最高。红无籽露×北冰红组合在1.0 μmol L^-1多效唑处理下萌芽率和成苗率最高，但红无籽露×昆香无核组合在0.2 μmol L^-1多效唑处理下萌芽率最好。不同的杂交组合取胚时间也不同。火焰无核×玫瑰香最佳取胚时间为授粉后39 d，昆香无核×北冰红为授粉后46 d，红宝石无核×北冰红及奇妙无核×双优为授粉后41 d。另外，向培养基中补充0.5 mg L^-1吲哚丁酸可以帮助畸形苗恢复为正常幼苗并获得生长健壮的子代。研究结果将为利用胚挽救技术选育无核葡萄新品种奠定基础。

Hexanol is a major compound contributing to the off-flavors (the bean-like odor) of soybean derived soymilk. The most effective way to reduce the off-flavors of soymilk is the screening and utilization of soybean cultivars with improved hexanol content. However, no genome-wide genetic analysis for this particular trait has been conducted to date. The objective of the present study was to dissect the genetic basis of hexanol content in soybean seed through genome-wide association analysis (GWAS). A total of 105 soybean accessions were analyzed for hexanol content in a three-year experiments and genotyped by sequencing using the specific locus amplified fragment sequencing (SLAF-seq) approach. A total of 25 724 single nucleotide polymorphisms (SNPs) were obtained with minor allele frequencies (MAF)>5%. GWAS showed that 25 quantitative trait nucleotides (QTNs) were significantly associated with the hexanol concentration in soybean seed. These identified QTNs distributed on different genomic regions of the 15 chromosomes. A total of 91 genes were predicted as candidate genes underlying the seed hexanol level and six candidates were predicted possibly underlying the seed hexanol by gene based association. In this study, GWAS has been proven to be an effective way to dissect the genetic basis of the hexanol concentration in multiple genetic backgrounds. The identified beneficial alleles and candidate genes might be valuable for the improvement of marker-assisted breeding efficiency for low hexanol level and help to explore possible molecular mechanisms underlying hexanol content in soybean seed.

Theileria luwenshuni and Theileria uilenbergi are important tick-borne pathogens and cause substantial losses to the sheep industry in China.  The improvement in detection techniques has allowed the identification of multi-homing parasitism in Theileria parasites.  Herein we evaluated the experimental infectivity of T. luwenshuni and T. uilenbergi in Chinese Kunming mice by screening blood samples of experimentally inoculated mice by microscopic examination (ME) and PCR.  T. luwenshuni infected Chinese Kunming mice and 20 mice inoculated with this parasite were positive by ME and PCR.  In addition, T. uilenbergi infected mice and 20 mice inoculated with this species were positive by ME and PCR.  However, the number of red blood cells and the levels of hemoglobin of 40 infected mice had no obvious changes in the course of infection.  Our results demonstrated the multi-homing parasitism of T. luwenshuni and T. uilenbergi, which were believed to be parasites of sheep and goats.  This study was the first to demonstrate the infection of T. luwenshuni and T. uilenbergi in Kunming mice. 

The present study reports the sublethal effects of the entomopathogenic fungus, Aschersonia aleyrodis (Webber) on Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae).  A fungal suspension of A. aleyrodis isolate Aa005 containing 1×10⁷ conidia mL^–1 was sprayed against B. tabaci on eggplant leaves under greenhouse conditions.  The effects of fungal application on survival as well as life table parameters of the whitefly were observed at different post inoculation periods.  The results indicated that A. aleyrodis can significantly affect the survival of 1st, 2nd, and 3rd nymphal instars of B. tabaci.  Developmental periods of different instar nymphs were not affected by fungal application.  A. aleyrodis spores persisted well and significantly affected the survivorship of young instar nymphs of B. tabaci at different post incubation periods.  Life table results suggested that A. aleyrodis has no impact on general fecundity and longevity of B. tabaci.  When the pathogen was exposed to the open environment and maintained for a relatively longer period, a reduction in the reproductive rate and intrinsic rate of increase was caused by the fungal spores, though the sublethal effects were not as good as the control treatment.  The results suggest that the ability of spores to suppress an increase in whitefly population persists well after incubation of spores to the external environment (up to 9 days).  

Received  8 September, 2017    Accepted  13 March, 2018

Bacillus thuringiensis Bt185 and its insecticidal spectrum-expanded engineering strains are considered as potential biocontrol agents to soil insect Holotrichia parallela, Holotrichia oblita or Anomala corpulenta.  Here we reported the complete genome of strain Bt185, it harbors eight plasmids, and plasmid pBT1850294 carries three cry8 genes.

Sewage sludge amendment (SSA) is an alternative waste disposal technique and a potential way to increase fertility of mudflats for crop growth. The present study aimed to assess the suitability of SSA by assessing the nitrogen (N) and phosphorous (P) uptakes, heavy metal accumulation, growth, biomass, and yield response of ryegrass (Lolium perenne L.) at 0, 30, 75, 150, and 300 t ha-1 SSA rates at various growth stages. The results showed that the highest biomass of ryegrass at seedling and vegetative stages were at 300 and 150 t ha-1 SSA rate, respectively. The increments of ryegrass yield at reproductive stage at 30, 75, 150, and 300 t ha-1 SSA rates were 98.0, 122.6, 88.1, and 61.2%, compared to unamended soil. N and P concentrations in ryegrass increased with increasing SSA rates at all stages except N and P in roots dropped significantly at 300 t ha-1 rate at vegetative stage. The metal concentration for Mn, Cu, Zn, Ni, Cd, Cr, and Pb in shoot of ryegrass at 300 t ha-1 SSA rate increased by 0.63-, 2.34-, 15.02-, 0.97-, 10.00-, 0.01- and 1.13-fold, respectively, compared to unamended soil. However, heavy metal concentrations in shoot of ryegrass were lower than the standard for forage products in China. The study suggested that sewage sludge amendment in mudflat soils might be feasible. However, the impacts of sludge application on edible crop plants and soil environment need further investigations.

In this study, nano-capsules of lansiumamide B (NCLB) was prepared by the microemulsion polymerization method to improve the nematicidal efficacy of lansiumamide B (LB). An optimal formulation was gained by orthogonal experiment design based on the encapsulation efficiency (En, %) value. The optimized NCLB were spherical and uniform under transmission electron microscopy (TEM). The mean particle size, zeta potential and En were (38.50±0.64) nm, (-70.5±0.76) mV and (95.13±1.16)%, respectively. The release profile indicated that the accumulated release of LB in NCLB reached up to 82% within 96 h. Effects of NCLB against Bursaphelenehus xylophilus and J2 of Meloidogyne incognita were reported in this paper. The nematicidal activity of NCLB has been remarkably increased, with LC50 values of 2.1407 mg L-1 and 19.3608 mg L-1, respectively, at 24 h after treatment. The disease progression and the average number of root knots of Ipomoea aquatica were 1.50 and 7.25, respectively, in the treatment of NCLB, at concentration of 200 mg L-1, significantly lower than the treatment of LB and ethoprophos. Compared to control, the treatments of NCLB, LB and ethoprophos leaded the disease progression to drop 68.42, 36.84 and 26.32%, respectively, and caused the average number of root knots to fall 83.94, 78.03 and 63.66%. These results suggested that NCLB, as a novel nematicides formulation, performed more efficient and longer effective maintenance against plant parasitic nematodes.

Transgenic Bt rice has been shown to be an effective means of controlling Lepidoptera pests of rice. However, the potential roles of transgenic rice on planthoppers and their predators need to be investigated before its commercialization. Population density, species dominance and population dynamics are important parameters of arthropods populations in field. So the impacts of three transgenic Bt rice strains expressing cry1Ab/cry1Ac, cry1C and cry2A on population density, species dominance and population dynamics of three species of planthoppers (Nilaparvata lugens, Sogatella furcifera and Laodelphax striatellus) and their three main predators (Cyrtorhinus lividipennis, Pirata subpiraticus and Theridium octomaculatum) were evaluated at three sites in Hubei Province, China, in the current study. The results showed that among three species of planthoppers, both in transgenic and non-transgenic rice field, the predominant species of planthoppers within phytophagous guild was S. furcifera at any site either growing season (46-50%). Significantly higher population density of N. lugens was observed in T2A-1 field relative to Minghui 63 field at Wuxue in 2010. The species dominance of predator, P. subpiraticus, in TT51 field was significantly higher than that in T1C-19 and T2A-1 fields in 2009 at Xiaogan site. Sampling date significantly influenced six arthropods except for P. subpiraticus in 2010. The interaction between rice strain×sampling date had no significant adverse effects on the population dynamics of three species of planthoppers and their predators, except for several individual species in 2009. The interaction among rice strain×sampling date×sampling site also had no significant effect on six arthropods except for S. furcifera in 2009. The results indicated that transgenic Bt rice expressing cry1Ab/cry1Ac, cry2A and cry1C had no significant adverse effects on the population dynamics of three planthoppers and their predators in most investigated data and sampling site.

Plants need to be efficient in nutrient management, especially when they face the temporal nutrient defficiencies. Understanding how crops respond to nitrogen (N) starvation would help in the selection of crop cultivars more tolerant to N deficiency. In the present work, the physiological responses of two wheat cultivars, Yannong 19 (YN) and Qinmai 11 (QM), to N starvation conditions were investigated. The two cultivars differed in biomass and N rearrangement between shoots and roots during N starvation. QM allocated more N to roots and exhibited higher root/shoot biomass ratio than YN. However, tissue measurement indicated that both cultivars had similar nitrate content in leaves and roots and similar remobilization rate in roots. Microelectrode measurement showed that vacuolar nitrate activity (concentration) in roots of QM was lower than that in roots of YN, especially in epidermal cells. Nitrate remobilization rates from root vacuoles of two cultivars were also identical. Moreover, vacuolar nitrate remobilization rate was proportional to vacuolar nitrate activity. During N starvation, nitrate reductase activity (NRA) was decreased but there were no significant differences between the two cultivars. Nitrate efflux from roots reduced after external N removal and QM seemed to have higher nitrate efflux rate.