Control of ovule development in Vitis vinifera by VvMADS28 and interacting genes

Seedless grapes are increasingly popular throughout the world,and the development of seedless varieties is a major breeding goal.In this study,we demonstrate an essential role for the grapevine MADS-box gene VvMADS28 in morphogenesis of the ovule.We found that VvMADS28 mRNA accumulated in the ovules of a seeded cultivar,‘Red Globe’,throughout the course of ovule and seed development,especially within the integument/seed coat.In contrast,in the seedless cultivar‘Thompson Seedless’,VvMADS28 was expressed only weakly in ovules,and this was associated with increased levels of histone H3 lysine 27 trimethylation(H3K27me3)within the VvMADS28 promoter region.RNAi-mediated transient suppression of VvMADS28 expression in‘Red Globe’led to reduced seed size associated with inhibition of episperm and endosperm cell development.Heterologous overexpression of VvMADS28 in transgenic tomatoes interfered with sepal development and resulted in smaller fruit but did not obviously affect seed size.Assays in yeast cells showed that VvMADS28 is subject to regulation by the transcription factor VvERF98,and that VvMADS28 could interact with the Type I/MβMADS-domain protein VvMADS5.Moreover,through DNA-affinity purification-sequencing(DAP-seq),we found that VvMADS28 protein specifically binds to the promoter of the grapevine WUSCHEL(VvWUS)gene,suggesting that maintenance of the VvMADS28–VvMADS5 dimer and VvWUS expression homeostasis influences seed development.Taken together,our results provide insight into regulatory mechanisms of ovule and seed development associated with VvMADS28.

Key indicators affecting maize stalk lodging resistance of different growth periods under different sowing dates

The accurate evaluation of maize stalk lodging resistance in different growth periods enables timely management of lodging risks and ensures stable and high maize yields.Here,we established five diferent sowing dates to create diferent conditions for maize growth.We evaluated the effects of the different growth conditions on lodging resistance by determining stalk morphology,moisture content,mechanical strength and dry matter,and the relationship between stalk breaking force and these indicators during the silking stage(R1),milk stage(R3),physiological maturity stage(R6),and 20 days after R6.Plant height at R1 positively affected stalk breaking force.At R3,the cofficient of ear height and the dry weight per unit length of basal internodes were key indicators of stalk lodging resistance.At R6,the key indicators were the coefficient of the center of gravity height and plant fresh weight.After R6,the key indicator was the coefficient of the center of gravity height.The crushing strength of the fourth internode correlated significanty and positively with the stalk breaking force from R1 to R6,which indicates that crushing strength is a reliable indicator of stalk mechanical strength.These results suggest that high stalk strength and low ear height beneft lodging resistance prior to R6.During and after R6,the cofficient of the center of gravity height and the mechanical strength of basal internodes can be used to evaluate plant lodging resistance and the appropriate time for harvesting in fields with a high lodging risk.

Pesticides Could Alleviate the Symptoms of Sweet Potato Virus Disease(SPVD)

In recent years,sweet potato virus disease( SPVD) has severely affected the production of sweet potato in China. In order to select chemical agents to prevent sweet potato from being infected with SPVD,14 pesticides were sprayed on the plants of sweet potato infected with SPVD,and the relative mRNA level of the viruses in the leaves and physiological indicators of sweet potato plants were detected. The results showed that after the application of most of the pesticides,the relative mRNA level of the two viruses that caused SPVD decreased,and the chlorophyll content and biomass of sweet potato infected with SPVD increased significantly or extremely significantly. Among the pesticides,BASF virus liquid,0. 1% physcion and Aolike powder for cucumber virus were proved to be the best,as the chlorophyll content and stem length of sweet potato increased significantly. The experiment indicated that the pesticides could reduce the harm of SPVD to sweet potato.

Screening and Genetic Characteristics of Breeding Materials of Silage Corn

[Objective] To analyze the effects of major agronomic traits on yield in maize inbred lines. [Method] Incomplete diallel cross between three single-cross hybrids and 19 parent materials of corn silage were performed, and the agronomic traits of the obtained 57 cross combinations were identified. [Result] The regression equations between biomass and four important indicators (grain yield, rows per ear, plant height and straw yield) affecting biomass of corn silage were established. The broad heritability of straw yield, plant height, rows per ear and ear length was higher than 50%. Genetic effects had a greater impact, while environmental factors had a smaller impact. Thus, it had great potential to improve these traits by genetic breeding. In addition, the broad heritability of biomass and grain yield was lower than 50%. [Conclusion] Biomass and grain yield have greater interaction effects on environment, and the environmental impact should be considered for selection.

Mining of candidate genes for grape berry cracking using a genome-wide association study

Fruit cracking is a common phenomenon during the growth and development of horticultural crops that seriously affects fruit yield and quality.However,there are few studies on the mining of candidate genes related to berry cracking.To better understand the genetic basis of grape berry cracking,we conducted a genome-wide association study(GWAS)of grape varieties.Based on the mixed linear model(MLM),we detected five single nucleotide polymorphism(SNP)loci associated with berry-cracking index and two SNP loci associated with berry-cracking type in two years.These loci were mainly distributed on four chromosomes,namely 1,2,3,and 18,and were associated with ten unique candidate berry-cracking genes.The gene expression patterns indicated that the candidate genes in the susceptible berrycracking variety were more abundant than in the resistant berry-cracking variety.Grape berry-cracking is a complex trait controlled by multiple genes,mainly including genes involved in polygalacturonase,copper transporter,and receptor-like proteins.The high expression of the candidate berry-cracking genes may promote the occurrence of berry cracking,so the present study helps to further elucidate the genetic mechanism of berry cracking.

Morphology of somatic embryogenesis and plantlet formation in tissue cultures of lantern tree (Koelreuteria bipinnata var.integrifoliola)

Somatic embryogenesis of Koelreuteria bipinnata var.integrifoliola was observed,plantlet formation in different types of somatic embryos was studied and the effect of abnormal embryos on plantlet formation was identified.Results show that somatic embryos of K.bipinnata var.integrifoliola include normal embryos,embryos with abnormal cotyledons,vitrified embryos,albino embryos,secondary embryos,linked embryos,embryos with abnormal growing points and embryos with expanding hypocotyl.After 40 d of callus culture,the response of normal somatic embryos from K.bipinnata var.integrifoliola was 26.7%,embryos with abnormal cotyledon 30.3% while other types of somatic embryos were below the 20% level.Most of normal embryos developed into plantlets and plantlet formation reached 94.9%.But the percentage of plantlet formation decreased apparently in abnormal embryos: the number of embryos with abnormal cotyledon declined to 76.1%,that of linked embryos to 47.4% and other types of abnormal embryos to below the 20% level.Albino embryos and embryos with abnormal growing point did not develop at all into plantlets.Embryos with abnormal cotyledons,linked embryos and embryos with abnormal growing points were observed during early stages of somatic embryogenesis,but vitrified,secondary and albino embryos and calli of embryos were observed at later stages.Increasing sucrose concentrations can decrease the occurrence of vitrified embryos,but the number of albino embryos decreased with an increasing in sucrose concentration.

Genetic Variation and Correlation Analysis on Seed Oil Content and Protein Content of Brassica campestris L.Germplasm Resources

The content of oil and protein in 84 germplasm materials of Brassica campestris L. from all over the country was tested. In Guiyang environment,the oil content and protein content of these materials showed abundant variation,and were divided into three groups. Correlation analysis showed that there was a significant negative correlation between oil content and protein content of B. campestris L. seeds,and the application and formation mechanism of the negative correlation were also discussed.

Physiological Response to High Temperature and Evaluation of Heat Tolerance of Different Grape Cultivars

[Objectives]This study was conducted to investigate the differences in the physiological responses of different grape cultivars to high temperature.[Methods]The 19 tested cultivars were selected from the grape germplasm resources pool of Turpan Research Institute of Xinjiang Academy of Agricultural Sciences.Twelve physiological indexes including gas exchange parameters,chlorophyll content,antioxidant enzyme activity and proline content were determined in grape leaves under field conditions during the middle period of local natural high temperature period(July,daily maximum air temperature>35℃).The heat tolerance of different cultivars was evaluated by fuzzy membership function analysis and optimum partitioning clustering of ordered samples.[Results](1)Under natural high temperature conditions in Turpan,the 19 tested grape cultivars responded differently to high temperature.‘Red Globe’,‘Fujiminori’,‘Beta’,‘Hetianhuang’had strong heat tolerance,while‘Thompson Seedless’,‘Hongqi Tezaomeigui’,‘Shuijing Wuhe’,‘Victoria’,‘Yatomi Rosa’and‘Crimson Seedless’had weak heat tolerance.(2)Among the 12 physiological indexes,malondialdehyde content and antioxidant enzyme activity were mostly different among various grape cultivars.The grape cultivars with strong heat tolerance,‘Red Globe’and‘Fujiminori’,had relatively lower malondialdehyde contents,while‘Beta’and‘Hetianhuang’had relatively higher malondialdehyde contents.But they had higher activity of antioxidant enzymes.(3)The results of fuzzy membership function analysis showed that the cumulative membership value(AR)of each physiological index was consistent with its apparent heat tolerance performance,suggesting that AR can be a potential index for the evaluation of heat tolerance of grape cultivars.Further cluster analysis classified the tested cultivars as strong,medium and weak.‘Red Globe’,‘Fujiminori’,‘Beta’and‘Hetianhuang’had strong heat tolerance.[Conclusions]This study provides a reference for grape cultivation under high temperature and stress and breeding of heat-tolerant varieties.

Effect of nitrogen and phosphorus application on soil nitrogen morphological characteristics and grain yield of oil flax

In order to identify effects of nitrogen(N)and phosphorus(P)on soil nitrogen morphological characteristics and grain yield of oil flax,a two-factor experiment was conducted in a randomized complete block design in typical semi-arid and hilly-gully area of Loess Plateau with 3 replicates in 2013 and 2014.Two levels of N application included 150 kg/hm2(N2)and 75 kg/hm2(N1).P application included 150 kg P2 O5/hm2(P2)and 75 kg P2 O5/hm2(P1).Temporal and spatial variation of soil nitrate nitrogen(NO3-N)and ammonium nitrogen(NH4+-N)contents in 0-60 cm soil layer,and relationship between soil NO3-N accumulation(SNA)and grain yield of oil flax were analyzed.Results showed that SNA increased with evaluated N application rate in different soil layers(0-20 cm,20-40 cm and 40-60 cm).With the increased P application,SNA increased at N1 level but decreased at N2 level.SNA under N2 P1 treatment increased by 73.33%in 2013 and 74.97%in 2014 respectively,compared with control treatment(CK)at maturity stage.Grain yield of oil flax also increased by 44.27%in 2013 and56.55%in 2014,compared with CK under the same treatment.Correlation analysis showed that SNA in different soil layers were respectively positively correlated with grain yield.In conclusion,this research suggested that the optimal fertilizer application rate was 150 kg N/hm2 and 75 kg P2 O5/hm2 in the Northwest of China.

Effects of plastic film mulching on flax(Linum usitatissimum L.) root distribution and water use efficiency

To evaluate effects of plastic film mulching on soil moisture, majority root distribution and water use efficiency (WUE), experiment was designed in flax field of Gansu,China. Three treatments including flat drill without mulching (CK), whole field soil plastic film mulched which covered with soil and bunch seeded (T1), and ridges mulched with plastic film and row-seeding in furrows (T2) were tested. Results indicated that mulching practice increased soil water storage compared to CK treatment in general. In both topsoil (0-30 cm) and underlying soil (30-100 cm) layer, T1 treatment had significantly greater (P<0.05) water storage than that in CK and T2 treatment. T1 treatment increased most significantly of soil water storage in 0-100 cm soil layer after rain, and also maintained high soil moisture at flax mature stage. Compared to CK, T1 and T2 produced obviously larger (P<0.05) taproot diameter and greater dry weight at both juvenile growth stage and first flowering stage, but had shorter lateral root length at all three stages. Consequently, seed yields and WUE with mulching treatment were increased by 22.3%-38.8% for T1 and 35.4%-56.2% for T2 compared to CK respectively. Film mulching is an effective cropping system for flax production in semiarid areas for improved root growth and enhanced soil moisture at different soil depths.

Using irrigation intervals to optimize water-use efficiency and maize yield in Xinjiang,northwest China

Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency(WUE) of high-yield maize under conditions of mulching and drip irrigation.A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days(labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days(D3, D6, D9, D12, and D15).In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize.The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha^-1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m-3, respectively.Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments.These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soilwater evaporation and evapotranspiration, and produce the highest yield and WUE.In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.

Adsorption and desorption of herbicide monosulfuron-ester in Chinese soils

Monosulfuron-ester is a new,low rate,sulfonylurea herbicide that is being promoted for annual broadleaf and gramineal weed control;however,there is a lack of published information on its behavior in soils.The adsorption and desorption of monosulfuronester by seven type soils were measured using a batch equilibrium technique.The results showed that the Freundlich equation fitted its adsorption and desorption well,and the Freundlich constant values (K f-ads ) ranged from 0.88 to 5.66.Adsorption isotherms were nonlinear with 1/n f-ads values < 1.Soil pH,organic matter (OM),and clay content were the main factors influencing its adsorption and desorption.Adsorption and desorption were negatively correlated with pH 4.0–8.0 while positively correlated with OM and clay content.The adsorption of monosulfuron-ester was mainly a physical process,because its free energy (?G) in seven soils was less than 40 kJ/mol.Monosulfuron-ester adsorption by three soils increased with increasing CaCl 2 concentration using CaCl 2 as a background electrolyte.Monosulfuron-ester desorption was hysteretic in all tested soils.

多酚控制茶树叶片短期分解过程的研究（英文）

目的:通过测定茶树叶片的分解速率及养分释放规律,研究茶多酚在茶树叶片分解过程中的作用。创新点:测定了茶树叶片在茶园地表的分解速率和养分释放规律,并确定了茶多酚/氮素比值在茶树叶片短期分解过程中的主导作用。首次利用高效液相色谱法监测了分解过程中儿茶素的变化规律。方法:采集成熟的茶树叶片,在室内风干后利用分解袋法测定其分解速率。分解袋放置于茶园地表用于模拟田间条件,逐月收集分解样品。实验结束后,测定各月份叶片的干重残留量、月均干重损失率、多酚等有机组分含量以及各元素含量。结论:茶树叶片的干物质损失规律可以"两相分解模型"进行描述,茶多酚/氮素比值是调控分解速率的主要因素。分解过程中,茶多酚的转换十分迅速,同时儿茶素单体的结构影响其分解速率:大部分的儿茶素单体在分解初始两个月内迅速消失,没食子酸(GA)、儿茶素没食子酸酯(CG)、儿茶素(GC)在分解后期少量检出,而其他儿茶素已不在检测限内。茶树叶片中大量多酚的存在及其特有性质可能影响着叶片中的养分释放过程。