Cross-resistance profile of mesosulfuron-methyl-resistant Italian ryegrass in the southern United States

Diclofop-resistant Lolium species (ryegrass) is a major weed problem in wheat production worldwide. This study was conducted to determine the resistance pattern of diclofop-resistant ryegrass accessions from the southern United States to mesosulfuron-methyl, a recently commercialized herbicide for ryegrass control in wheat; to determine the cross-resistance pattern of a Lolium multiflorum Lam. (Italian ryegrass) accession, 03-1, to acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibitors; and to determine the resistance mechanism of Italian ryegrass to mesosulfuron-methyl. Seventeen ryegrass accessions from Arkansas and Louisiana, including standard resistant and susceptible accessions, were used in this experiment. Fourteen of the 17 accessions were more resistant (four- to > 308-fold) to diclofop than the standard susceptible biotype. One accession, 03-1, was resistant to mesosulfuron-methyl as well as to other ALS inhibitor herbicides such as chlorsulfuron, imazamox and sulfometuron. Accession 03-1, however, did not show multiple resistance to the ACCase inhibitor herbicides diclofop, fluazifop, clethodim, sethoxydim and pinoxaden, nor to glyphosate. The in vivo ALS activity of the 03-1 biotype was less affected by mesosulfuron-methyl than the susceptible biotype. This indicates that the resistance mechanism of Italian ryegrass to mesosulfuron-methyl is partly due to an alteration in the target enzyme, ALS. It is concluded that diclofop-resistant ryegrass in the southern United States can be generally controlled by mesosulfuron-methyl. However, mesosulfuron-methyl must be used with caution because not all ryegrass populations are susceptible to it. There is a need for more thorough profiling of ryegrass resistance to herbicides.     

优质鲜食糯玉米杂交种虞珑糯1612的选育与应用

虞珑糯1612是江苏省常熟市农业科学研究所、常熟市农业科技发展有限公司选育的优质鲜食糯玉米单交种,其母本da11和父本wd11y均是自选自交系;该品种食用口感软糯香甜、色泽美观;2018年、2019年参加江苏省糯玉米新品种区域试验、2020年进入江苏省糯玉米新品种生产试验并完成试验程序,2021年4月通过江苏省农作物品种审定委员会审定。     

Optimizing the use of breed types in developing country livestock production systems: a neglected research area

Developing country livestock production systems are diverse and dynamic, and include those where existing indigenous breeds are currently optimal and likely to remain so, those where non‐indigenous breed types are already in common use, and systems that are changing, such as by intensification, where the introduction of new breed types represents significant opportunities. These include opportunities to improve the livelihood of the world's poor, increase food and nutrition security and enhance environmental sustainability. At present, very little research has focused on this issue, such that significant knowledge gaps in relation to breed‐change interventions remain. The purpose of this study is to raise awareness of this issue and suggests strategic research areas to begin filling these knowledge gaps. Such strategic research would include (i) assessing the impact of differing breed types in developing country livestock productions systems, from a range of viewpoints including intrahousehold livelihood benefit, food and nutrition security at different scales, and environmental sustainability; (ii) identification of specific livestock production systems within developing countries, and the type of livestock keepers within these system, that are most likely to benefit from new breed types; and (iii) identification of new breed types as candidates for in‐situ testing within these systems, such as through the use of spatial analysis to identify similar production environments combined with community acceptance studies. Results of these studies would primarily assist stakeholders in agriculture, including both policy makers and livestock keepers, to make informed decisions on the potential use of new breed types.     

Identification of Mycobacterium spp. isolated from snakehead, Channa striata (Fowler), and Siamese fighting fish, Betta splendens (Regan), using polymerase chain reaction–reverse cross blot hybridization (PCR–RCBH)

A variety of methods have been used to identify Mycobacterium spp. isolated from snakehead and Siamese fighting fish, including biochemistry, mycolic acid profiles and antibody-based methods. However, these methods are unable to differentiate between different species of Mycobacterium . Polymerase chain reaction (PCR) followed by reverse cross blot hybridization (RCBH) was adapted in this study to speciate aquatic mycobacteria. The method was highly specific for Mycobacterium spp. and identified the bacteria to species level with a detection limit of 100 fg DNA, equivalent to 20 mycobacteria. Twenty-nine isolates previously collected and cultured from Siamese fighting fish (10 isolates) and snakehead (19 isolates) during outbreaks of mycobacteriosis were analysed using PCR–RCBH. Six of the Siamese fighting fish isolates and nine of the snakehead isolates were identified as Mycobacterium fortuitum , while the remainder were classified as M. marinum . Notably, two isolates recovered from snakehead and Siamese fighting fish, previously identified as M. poriferae and M. piscicida , respectively, were confirmed to be M. fortuitum .     

利用不亲和野生种育成花生新品种花育56号

花育56号,原代号09-测S8,系采用花生不亲和野生种Arachis glabrata Benth作父本、栽培种四粒红为母本杂交,通过果针离体培养获得可育杂种,选取F2优良单株与栽培品种花37回交,经系谱法选育而成的珍珠豆型花生新品种。2013年通过安徽省品种鉴定(皖品鉴登字第1205004),2014年通过吉林省品种登记(吉登花生2014002)。     

玉米单倍体成株诱导率和加倍率研究

利用吉诱SM6278-2对31份不同种质基础材料进行单倍体杂交诱导,在三亚南滨农场基地进行自然加倍自交试验。结果表明,不同材料单倍体诱导成株率存在差异,差异不显著;单倍体诱导成株率最高达4.7%,最低为0.3%,平均为1.0%;不同材料单倍体雄穗加倍率存在极显著差异,最高为47.1%,最低为1.6%,平均为16.7%;不同材料单倍体结实株率存在极显著差异,最高为23.5%,最低为0%,平均为6.1%;不同材料单倍体雄穗加倍形成的花粉亲和力差异极显著。单倍体雄穗加倍与自交结实密切相关,单倍体雄性的育性问题是单倍体自交结实性的关键因素。     

玉米不同基础群体选系高效测验系筛选

采用常规方法从新组配的14个Reid类F₁基础群体中选育自交系,对S₄代选系与其他三大优势类群10个骨干自交系为测验系组配成的1 902个测交组合进行田间鉴定,分析从中筛选出428个优组合的子粒产量和百粒重表现及其与选系基础群体和测验系的关系。结果表明,来源于不同基础群体和同一基础群体的不同选系与不同优势类群和同一优势类群不同测验系间测交组合的子粒产量和百粒重均存在较大差异。来源于基础群体BP5选系子粒产量和百粒重的一般配合力较高,其与测验系昌7-2间子粒产量和百粒重以及与测验系浚926间百粒重的特殊配合力均较高;BP7群体选系百粒重和子粒产量、BP6群体选系百粒重和BP9群体选系子粒产量的一般配合力均较高;BP1、BP2和BP5群体选系与测验系浚926间组合的百粒重,BP6、BP7群体选系与测验系浚926间组合子粒产量,BP4、BP5、BP10和BP12群体选系与测验系昌7-2间组合百粒重,BP2和BP10群体选系与测验系昌7-2间组合子粒产量及BP4群体选系与测验系HL02间组合子粒产量的特殊配合力均较高。昌7-2、浚926和HL02是比较适宜的高效测验系。     

甜高粱与粒用高粱正反交F_1代农艺性状差异分析

对甜高粱与粒用高粱正反交F1代杂交种的杂种优势及其主要农艺性状进行了比较分析。结果表明:只有穗粒重表现出明显的群体超亲优势,按均值大小排顺序为:单株生物产量穗粒重株高穗长锤度生育期。甜高粱与粒用高粱正反交F1代主要农艺性状单株生物产量、含糖量、穗粒重、株高、穗长和生育期6个性状之间的差异不明显。     

猪、犬旋毛虫成虫免疫原性试验

通过提取猪、犬旋毛虫成虫抗原，制备成虫油佐剂免疫原，在小鼠体内进行同源特异性免疫试验和交叉免疫试验。试验得到猪旋毛虫成虫抗原同源免疫减虫率为５５．８０％，其对犬旋毛虫的交叉免疫减虫率是３５．１１％；犬旋毛虫成虫抗原同源免疫的减虫率为３９．００％，其对猪旋毛虫的交叉免疫减虫率是２４．９６％。试验结果揭示，猪、犬旋毛虫成虫具有一定的免疫原性，其交叉免疫减虫率低于同源特异性免疫。猪旋毛虫成虫抗原对犬旋毛虫的交叉免疫与犬旋毛虫自身的同源特异性免疫差异不显著。     

浅析严格控制钢筋保护层厚度的原因及其保证措施

论述了钢筋砼保护层厚度控制的重要性及钢筋砼保护层防控措施。