Identification and evaluation of high nitrogen nutrition efficiency in rapeseed(Brassica napus L.)germplasm

To establish identification and evaluation methods of N(nitrogen)absorption and utilization of rapeseed(Brassica napus L.),difference of N nutrition efficiency(NNE)among rapeseed germplasms and relationship between NNE and plant traits under various N application rates were analyzed in this research.Pot cultivating experiments were conducted to investigate NNE with 3 N application rates in soil(0.05,0.2 and 0.3 g/kg).A total of 12 rapeseed germplasms were planted,nitrogen absorption efficiency(NAE)and nitrogen utilization efficiency(NUE)in seedling stage,bolting stage,initial flowering stage,final flowering stage,and maturity stage were obtained.Results showed that bolting stage was the best period for NAE identification and evaluation.Low N application rate in soil(0.05 g/kg)was the best for NAE,and the indirect indexes were basal stem diameter,plant root dry weight and above ground plant dry weight.Maturity stage was the best period for NUE identification and evaluation.High N application rate in soil(0.3 g/kg)was the best for NUE,and indirect indexes were above ground plant dry weight and basal stem diameter.N application rates of 0.05 g/kg in soil was the best for nitrogen harvest index at maturity stage,and indirect indexes was number of pods per plant.Plant traits of rapeseed germplasms affected NNE.Higher basal stem diameter,plant root dry weight and above ground plant dry weight at bolting stage under low N application rate were important characteristics of N absorption in rapeseed.Higher above ground plant dry weight and basal stem diameter at maturity stage under high N application rate were important characteristics of N utilization.Higher number of pods per plant at maturity stage under lowe N application rate was an important characteristic of N harvest index.These results provided a reliable index for N management and provided theoretical basis for guiding rapeseed breeding.

TBtools: An Integrative Toolkit Developed for Interactive Analyses of Big Biological Data

The rapid development of high-throughput sequencing techniques has led biology into the big-data era.Data analyses using various bioinformatics tools rely on programming and command-line environments,which are challenging and time-consuming for most wet-lab biologists.Here,we present TBtools(a Toolkit for Biologists integrating various biological data-handling tools),a stand-alone software with a userfriendly interface.The toolkit incorporates over 130 functions,which are designed to meet the increasing demand for big-data analyses,ranging from bulk sequence processing to interactive data visualization.A wide variety of graphs can be prepared in TBtools using a new plotting engine("JIGplot")developed to maximize their interactive ability;this engine allows quick point-and-click modification of almost every graphic feature.TBtools is platform-independent software that can be run under all operating systems with Java Runtime Environment 1.6 or newer.It is freely available to non-commercial users at https://github.com/CJ-Chen/TBtools/releases.