Estimation of the potential geographical distribution of a new potato pest(Schrankia costaestrigalis) in China under climate change

Global food security is threatened by the impacts of the spread of crop pests and changes in the complex interactions between crops and pests under climate change.Schrankia costaestrigalis is a newly-reported potato pest in southern China.Early-warning monitoring of this insect pest could protect domestic agriculture as it has already caused regional yield reduction and/or quality decline in potato production.Our research aimed to confirm the potential geographical distributions(PGDs)of S.costaestrigalis in China under different climate scenarios using an optimal MaxEnt model,and to provide baseline data for preventing agricultural damage by S.costaestrigalis.Our findings indicated that the accuracy of the optimal MaxEnt model was better than the default-setting model,and the minimum temperature of the coldest month,precipitation of the driest month,precipitation of the coldest quarter,and the human influence index were the variables significantly affecting the PGDs of S.costaestrigalis.The highly-and moderately-suitable habitats of S.costaestrigalis were mainly located in eastern and southern China.The PGDs of S.costaestrigalis in China will decrease under climate change.The conversion of the highly-to moderately-suitable habitat will also be significant under climate change.The centroid of the suitable habitat area of S.costaestrigalis under the current climate showed a general tendency to move northeast and to the middle-high latitudes in the 2030s.The agricultural practice of plastic film mulching in potato fields will provide a favorable microclimate for S.costaestrigalis in the suitable areas.More attention should be paid to the early warning and monitoring of S.costaestrigalis in order to prevent its further spread in the main areas in China’s winter potato planting regions.

Relationship Among Yield Components and Selection Criteria for Yield Improvement in Early Rapeseed (Brassica napus L.)

The objective of this study was to determine the relationship between seed yield and other important agronomic traits of early-maturing rapeseed as a rotation crop in a double-cropping rice area using Pearson＇s correlation coefficient as well as to estimate direct and indirect effects of specific yield component traits on seed yield via path analysis. Nineteen rapeseed genotypes were grown at ten environments in South China during 2008-2009 and 12 characters were evaluated. Analysis of variance showed that environment had a significant impact on all characters. For most characters the genotype by environment interaction was weak and not statistically significant. Simple correlation analysis indicated that the number of primary branches （PB）, number of pods on the main raceme （PR）, and number of seeds per pod made significant contributions to seed yield per plant （SYP）, while 1 000-seed weight was negatively correlated with SYP （r=-0.485, P0.05）. Furthermore, number of pods per plant （PP）, PB, and PR had the greatest direct effects on SYP. In addition, PP and PB were the best indicators to predict seed yield in stepwise regression analysis. Finally, yield component differences between early- and medium-maturity varieties were compared; this showed that to improve the seed yield of early varieties, more emphasis should be given to increase PP, PB, and PR, and reduce plant height and shortening of growth duration in breeding practice.

First record of the golden potato nematode Globodera rostochiensis in Yunnan and Sichuan provinces of China

The potato cyst nematodes(PCN) Globodera rostochiensis(Wollenweber) Skarbilovich,1959 is considered the most damaging nematode pest of potato worldwide that causes significant yield losses,and this nematode is recognized and listed as a quarantine nematode in many countries(EPPO 2017).China is currently the largest producer of potato in the world.

Identification of Heterodera schachtii on sugar beet in Xinjiang Uygur Autonomous Region of China

The sugar beet cyst nematode,Heterodera schachtii,is a major parasite of sugar beet which has been recognized and listed as a quarantine nematode in China and more than 20 countries and regions worldwide.A survey for important nematodes was undertaken in the sugar beet planting area of China during 2015-2018,and numerous cysts were collected from sugar beet fields in Xinyuan County,Xinjiang Uygur Autonomous Region of China.The observations of morphological and morphometric characteristics revealed that cysts,vulval cones and second-stage juveniles of the Xinjiang population were in the same range of each other and within those of other reported H.schachtii populations.Molecular analysis of rDNA-ITS,28S-D2/D3 and mtDNA cytochrome c oxidase subunit 1(COI)gene sequences suggested that the Xinjiang population clustered in a branch with those foreign populations,and the sequence similarity was as high as 99.81-100%.Moreover,this result was confirmed by PCR assay with species-specific primer SHF6 and rDNA2 of H.schachtii,and the pathogenicity test confirmed successful Xinjiang population reproduction in both plant hosts.In conclusion,based on morphological and molecular characterization,this study confirmed that the cyst nematode population collected from sugar beet fields in Xinjiang is H.schachtii.As far as we know,this is the first report of H.schachtii on sugar beets in Xinjiang,China.

Assessment of the contribution percentage of inherent soil productivity of cultivated land in China

The contribution percentage of inherent soil productivity(CPISP)refers to the ratio of crop yields under no-fertilization versus under conventional fertilization with the same field management.CPISP is a comprehensive measure of soil fertility.This study used 1086 on-farm trials(from 1984-2013)and 27 long-term field experiments(from 1979-2013)to quantify changes in CPISP.Here,we present CPISP3 values,which reflect the CPISP states during the first three years after site establishment,for a series of sites at different locations in China collected in 1984-1990(the 1980s),1996-2000(the 1990s),and 2004-2013(the 2000s).The results showed that the average CPISP3 value for three crops(wheat,rice,and maize)was 53.8%.Historically,the CPISP3 in the 1990s(57.5%)was much higher than those in the 1980s(50.3%),and the 2000s(52.0%)(P≤0.05).Long-term no-fertilization caused CPISP levels to gradually decline and then stabilize;for example,in a mono-cropping system with irrigation,the CPISP values in Northwest and Northeast China declined by 4.5 and 4.0%,respectively,each year for the first ten years,but subsequently,the CPISP values stabilized.In contrast,the CPISP for upland crops in double-cropping systems continued to decrease at a rate of 1.1%per year.The CPISP for upland-paddy cropping decreased very slowly(0.07%per year),whereas the CPISP for paddy cropping decreased sharply(3.1%per year,on average)for the first two years and then remained steady during the following years.Therefore,upland crops in double-cropping systems consume the most inherent soil productivity,whereas paddy fields are favourable for maintaining a high level of CPISP.Overall,our results demonstrate a need to further improve China’s CPISP3 values to meet growing productivity demands.

A review: status and prospect of heterosis prediction in rapeseed(Brassica napus L.)

Heterosis has been widely exploited and utilized in rapeseed breeding. Reliable and precise prediction techniques of heterosis contributed in accelerating the crossbreeding and reducing the cost of large-scale field evaluation. Combined with our work in last decades, this review summarized the progress on heterosis prediction of rapeseed (Brassica napus L.), compared the efficiency of different methods, and proposed its prospect.

Effect of aerial spray adjuvant applying on the efficiency of small unmanned aerial vehicle for wheat aphids control

Small unmanned aerial vehicles(UAVs)have been widely used in different aspects of modern farming management,including pest and disease control in China in recent years.In this study,the spray performance of a small plant protection UAV at low volume spray was evaluated by adjusting the pesticide dosage and adding aerial spraying adjuvants.Droplet deposition,droplet density,coverage,control effect and pesticide residue from field trials were assessed.In addition,the residue and control effect of UAV spray were compared to manual knapsack at high volume spray.The results showed that,the adjuvant applying improved the efficiency of UAV spray.Also,the adjuvant applying reduced the dosage of imidacloprid by 20%.However,there was no significant difference on initial residue between UAV spray and knapsack spray.Thus,plant protection UAV spraying pesticide by adding appropriate adjuvant showed the ability of improving the pesticide effectiveness by improving the control efficiency,reducing the pesticide dosage and residue.