Yield Characteristics of a New High-quality Disease-resistant Wheat Variety Chuanmai 618

[Objectives]The paper was to analyze the yield characteristics of a new high-quality disease-resistant wheat variety Chuanmai 618.[Methods]The yield characteristics of Chuanmai 618 were analyzed using the AMMI model and GGE biplot based on data from a 2-year regional test and a 1-year production test.[Results]The analysis of the AMMI model for the 2-year regional test indicated that Chuanmai 618 had a moderate yield and good stability.During the production test,Chuanmai 618 had an average yield of 450.52 kg/666.7 m^(2),an effective spike of 235700 spike/666.7 m^(2),a 1000-seed weight of 47.93 g,and a kernel number per spike of 47.28.The AMMI analysis sequencing graph showed that the varieties were ranked in the following order:Zhongkemai 1816>Chuanmai 618>Shumai 1958>Chuanyu 42>Mianmai 367>Xikemai 5518.According to the GE analysis,Chuanmai 618 had comparative advantages.[Conclusions]The new wheat variety Chuanmai 618 is a high-quality disease-resistant variety with good yield and stability.

The KL system in wheat permits homoeologous crossing over between closely related chromosomes

The Chinese wheat landrace Kaixianluohanmai(KL)expresses the ph-like phenotype.A major QTL,QPh.sicau-3A(syn.phKL),responsible for this effect has been mapped to chromosome arm 3AL.This study presents some characteristics of homoeologous pairing and recombination induced by phKL.In KL haploids,the level of homoeologous pairing was elevated relative to Ph1 Chinese Spring(CS)haploids.There was a clear preference for A–D pairing and less frequent for A–B and B–D,reflecting the higher levels of affinity between genomes A and D in wheat.The characteristics of pairing were affected by temperature and magnesium ion supplementation.The suitability of phKL for chromosome engineering was tested on three pairs of homoeologues:2Sv-2B,2Sv-2D,and 2RL-2BL.The recombination rates were 1.68%,0.17%,and 0%,respectively.The phKL locus in KL induced a moderate level of homoeologous chromosome pairing and recombination when the Ph1 locus of wheat was present,both in wheat haploids and hexaploids.The Ph1-imposed criteria for chromosome pairing and crossing over were relaxed to some degree,permitting homoeologous crossing over but only between closely related chromosomes;there was no crossing over between more differentiated chromosomes.Therefore,the phKL system(QPh.sicau-3A)can be a useful tool in chromosome engineering of wheat to transfer genes from closely related species with the benefit of reduced genomic chaos generated by the ph1b mutation.

四川省小麦育成品种系谱分析及发展进程

品种系谱蕴含亲本来源、选育方式、亲缘关系等大量信息,对揭示农作物品种演变特点、规律并最终指导育种实践具有重要意义。本文汇总了四川省1936~2017年间326个小麦品种的系谱信息,对育种方式、亲本构成、高频亲本及骨干亲本的变化、遗传贡献、易位系及人工合成种质分布等情况进行了梳理与分析。从20世纪30年代至今,四川省育种家从大量材料中选用387个直接亲本,采用杂交育种等方式,配制数千个组合,从256个组合中选育出314个品种,对四川省小麦生产做出了重要贡献,同时也为小麦育种提供了更为优异的材料基础。四川省小麦育种经历了从无到有,从主要依靠引进材料、地方品种到自主创制材料的过程;高频亲本、骨干亲本随育种进程推进而逐渐变化。易位系和人工合成种质对四川省小麦育种贡献巨大。育种目标的一致性必然导致遗传多样性散失和遗传基础脆弱,今后重点应加强资源的创制、保护和利用。本文通过育成品种的系谱梳理,对四川省小麦的育种发展进程进行了分析,以期为未来种质资源的收集创制和育种研究提供重要参考信息。

Primary Question and Hypothesis Testing in Randomized Controlled Clinical Trials

本文中我们简要地回顾并提供了医疗和公共研究设计中使用的一些基本概念的有关注意事项,特别是主要问题、假设检验、和样本量。此外,我们还讨论了最近几年的一些扩展和发展。

Hierarchical graphene@MXene composite foam modified with flower-shaped FeS for efficient and broadband electromagnetic absorption

Developing high-performance broadband microwave absorption material becomes an urgent concern in the field of electromagnetic protection.In this work,an ultralight magnetic composite foam was con-structed by electrostatic self-assembly of MXene on the surface of graphene skeletons,and subsequent hydrothermal anchoring of flower-shaped FeS clusters.Under the synergistic effect of MXene coating in-creasing conductive loss and FeS clusters improving magnetic loss,the rational construction of hierarchi-cal impedance structure in foam can effectively promote the entrance and consumption of more incident electromagnetic waves.The minimum reflection loss(RL min)reaches-47.17 dB at a thickness of 4.78 mm,and the corresponding effective absorption bandwidth(EAB)is up to 6.15 GHz.More importantly,the microwave absorption performance of composite foam can be further optimized by controlling the load-ing of MXene and thermal treatment at a low temperature.The maximum of EAB for GMF-300 can be extended to an unprecedented value of 11.20 GHz(covering 6.10-17.30 GHz).

Ultrathin,flexible,and oxidation-resistant MXene/graphene porous films for efficient electromagnetic interference shielding

Designing and fabricating efficient electromagnetic interference(EMI)shielding materials becomes a significant and urgent concern.Hence,a novel ultrathin,flexible,and oxidation-resistant MXene-based graphene(M-rGX)porous film is successfully fabricated by electrostatic self-assembly between MXene and graphene oxide(GO)nanosheets,and subsequently thermal annealing under hydrogen-argon atmosphere.The rapid breakaway of functional groups on GO and MXene sheets induces formation of porous conductive network in film,thereby facilitating efficient shielding for incident electromagnetic waves.The optimal absolute shielding effectiveness(SSE/t)value of 76,422 dB·cm2·g−1 can be achieved at a thinner thickness of 15μm.More importantly,the effective removal of functional groups on MXene conspicuously improves the oxidation resistance of the film,endowing it with an excellent durability(12 months)in EMI shielding performance.

四川杂交小麦研究进展及展望

四川杂交小麦研究历经50余载,至今仍在继续.杂交小麦的研究主要利用三系法和两系法,三系法中的T型三系研究较为系统,从不育系的选育、恢复的改良以及组合配制方面均进行了长期研究,尤其针对T型三系恢复源窄,提出了主效恢复基因选择法,极大提高了恢复系的选择效率.在温光敏两系杂交小麦研究领域,对其发现、育性转化、改良、组合配制等方面进行了研究,应用成果也很显著,培育出通过国家审定的绵阳32和绵杂麦168、四川省审定的绵杂麦512和绵杂麦638;在化杀两系杂交小麦选育方面,对药剂类型、施药剂量、用药时期等进行研究,培育出2个通过四川省审定的化杀杂交小麦新品种川麦59和川麦69并释放生产应用.同时,针对四川小麦生产实际,对杂交小麦的发展提出了展望.

Synthesizing double haploid hexaploid wheat populations based on a spontaneous alloploidization process

Doubled haploid （DH） populations are useful to scientists and breeders in both crop improvement and basic research. Current methods of producing DHs usually need in vitro culture for extracting haploids and chemical treatment for chromosome doubling. This report describes a simple method for synthesizing DHs （SynDH） especially for allopolyploid species by utilizing meiotic restitution genes. The method involves three steps： hybridization to induce recombination, interspecific hybridization to extract haploids, and spontaneous chromosome doubling by selfing the interspecific Fis. DHs produced in this way contain recombinant chromosomes in the genome（s） of interest in a homogeneous background. No special equipment or treatments are involved in the DH production and it can be easily applied in any breeding and/or genetic program. Triticum turgidum L. and Aegilops tauschii Coss, the two ancestral species of common wheat （Triticurn aestivum L.） and molecular markers were used to demonstrate the SynDH method.

Cache Pollution Prevention Mechanism Based on Deep Reinforcement Learning in NDN

As a representative architecture of contentcentric paradigms for the future Internet,named data networking(NDN)enables consumers to retrieve content duplicates from either the original server or intermediate routers.Each node of NDN is equipped with cache that buffers but not validates the data,making it vulnerable to various attacks.Cache pollution,one of the specific attacks in NDN,fraudulently alters the cached contents by excessively requesting worthless information,squeezing the space of real popular contents and thus degrading the experience of normal users.In order to address the issue,this paper proposes a defense scheme based on deep reinforcement learning(DRL)against cache pollution attack,in which whether a data packet is to be cached is decided by a trained intelligent agent,that is adaptive to dynamic network states and following long term rewards,the accumulative data-requesting delays.Finally,the DRL-based scheme is evaluated and compared to two other existing schemes.Experimental results show that the proposed defense mechanism outperforms the others significantly,and is proved to be effective against cache pollution attacks.