Mapping of powdery mildew resistance genes transferred to common wheat from wild emmer wheat revealed three functional Pm60 haplotypes

Powdery mildew(PM),caused by Blumeria graminis f.sp.tritici(Bgt),is one of the destructive wheat diseases worldwide.Wild emmer wheat(Triticum turgidum ssp.dicoccoides,WEW),a tetraploid progenitor of common wheat,is a valuable genetic resource for wheat disease resistance breeding programs.We developed three hexaploid pre-breeding lines with PM resistance genes derived from three WEW accessions.These resistant pre-breeding lines were crossed with susceptible common wheat accessions.Segregations in the F2populations were 3 resistant:1 susceptible,suggesting a single dominant allele in each resistant parent.Mapping of the resistance gene in each line indicated a single locus on the long arm of chromosome 7A,at the approximate location of previously cloned Pm60 from T.urartu.Sanger sequencing revealed three different Pm60 haplotypes(Hap 3,Hap 5,and Hap 6).Co-segregating diagnostic markers were developed for identification and selection of each haplotype.The resistance function of each haplotype was verified by the virus-induced gene silencing(VIGS).Common wheat lines carrying each of these Pm60 haplotypes were resistant to most Bgt isolates and differences in the response arrays suggested allelic variation in response.

后疫情时期契约农业对农户收入信心影响的实证研究

本文以新型冠状病毒肺炎事件为例,研究后疫情时期契约农业是否有助于提升农户收入信心。首先,基于生产函数理论建立数理模型,分析契约农业对农户收入信心的影响。其次,将农户从签订契约的合同商处得到的社会支持分为后疫情时期采取的有效防控措施、提供饲料来源等降低生产困难、疫情及生产相关信息、协助农户更快恢复生产生活四个方面,研究契约农业如何通过社会支持影响农户收入信心。选取229户农户调查问卷数据进行实证分析,估计结果显示,契约农业提升农户收入信心。为避免遗漏变量导致估计结果偏差,实证分析时引入户主及家庭特征等控制变量。最后,文章建议地方政府应该加大契约农业的推广,并加强疫情及生产等信息的宣传,加快本地生产生活恢复等。研究结论为契约农业的进一步推广提供理论解释,并对于后疫情时期提升农户收入信心、确保农户稳定增收具有指导意义。