镉低积累水稻品种筛选及其在镉超标稻田的表现评价

【目的】筛选镉低积累型水稻品种并开展镉超标稻田表现评价研究,为广西中低度镉污染稻田生产安全稻米提供品种和数据参考。【方法】以114份(V1~V114)水稻低镉品种育种材料为试验对象,从中筛选综合性状优良且籽粒表现为镉低积累的目标材料;对目标材料进行大田试验和盆栽试验验证,测定其在广西不同试验点的农艺性状和精米镉含量。【结果】初步筛选试验的114份参试材料中,除V102的精米镉含量低于最低检测值外,其余113份水稻育种材料的精米镉含量范围在0.01~0.35 mg/kg,平均值为0.10 mg/kg,筛选得到综合性状优良且精米镉含量较低的材料V111(审定后名称为桂育12)。桂育12在中低度镉污染区大田验证种植时,精米镉含量(0.01~0.10 mg/kg)未超出国家标准GB 2762—2017《食品安全国家标准食品中污染物限量》规定的限值(0.20 mg/kg)。盆栽试验结果表明,在pH为5.0,土壤镉含量3.0 mg/kg条件下,桂育12精米镉含量(0.34 mg/kg)有超标风险;各试验中土壤镉含量对桂育12部分农艺性状指标影响显著(P<0.05),但属于品种种植的正常波动范围,对米质和产量的综合影响有限。【结论】从114份水稻材料中筛选出的镉低积累品种桂育12,经多年多点试验验证,在中低度镉污染稻田产出的稻米镉含量不超标,籽粒镉低积累性状较稳定,综合性状表现受土壤镉含量影响较小,可在广西中低度镉污染稻田推广应用。

广西地方稻种资源的收集与鉴定评价

【目的】收集鉴定广西地方稻种资源,为广西地方稻种资源保护和利用提供科学依据。【方法】2015─2019年,通过“第三次全国农作物种质资源普查与收集行动”项目的实施,对广西61个县(区、市)188个乡(镇)265个村(屯)的地方稻种资源进行系统调查和收集,对收集资源的分布特点和种质类型进行分析,对各表型性状进行鉴定评价。【结果】从广西各地收集地方稻种资源476份。从水平分布来看,广西地方稻种资源在广西四大稻作区均有分布,稻种资源主要集中分布于融水、上思、凤山、资源、隆林和东兰等6个经济相对不发达的边远地区。从垂直分布上分析,稻种资源主要分布在0~400 m的低海拔地区,收集资源232份,占收集总数的48.74%。广西地方稻种资源多样性丰富,包含籼稻、粳稻、早稻、中晚稻、粘稻、糯稻、水稻、陆稻、深水稻及有色稻等类型,且多数的农艺性状具有较丰富的变异类型。收集及鉴定评价出香糯、米粉特用、大穗、大粒等珍稀特异地方稻种资源9份。【结论】广西地方稻种资源多样性丰富,且普遍具有株高较高、穗粒数多、结实率高的特点。收集、鉴定评价出珍稀特异地方稻种资源9份,可用于产业开发及育种。

回交导入系稻瘟病抗性鉴定评价与分子检测分析

【目的】通过对回交导入系进行稻瘟病抗性鉴定评价和分子检测,可以为水稻抗病育种和基础研究提供优质亲本和理论证据。【方法】利用优良杂交稻恢复系测253和桂649为轮回亲本,分别与3个水稻品种进行杂交、回交,构建了6个回交导入系群体。然后,采取自然诱发和人工接种方式对导入系进行稻瘟病鉴定评价,并结合分子标记技术检测导入系群体等位基因的分布频率。【结果】鉴定评价出抗穗颈瘟导入系68个,其中兼抗苗叶瘟的导入系有21个。最终筛选出广谱、高抗稻瘟病的优良恢复系4个。另外,卡方检测发现,由于稻瘟病抗性的定向选择,导入系选择群体在染色体5个位点上的等位基因发生了偏分离。【结论】回交导入系可以成为高效挖掘水稻优异基因资源以及培育优良水稻新品种的理想平台。

Application of a novel detection approach based on non-dispersive infrared theory to the in-situ analysis on indicator gases from underground coal fire

Coal mine fires,which can cause heavy casualties,environmental damages and a waste of coal resources,have become a worldwide problem.Aiming at overcoming the drawbacks,such as a low analysis efficiency,poor stability and large monitoring error,of the existing underground coal fire monitoring technology,a novel monitoring system based on non-dispersive infrared(NDIR)spectroscopy is developed.In this study,first,the measurement principle of NDIR sensor,the gas concentration calculation and its temperature compensation algorithms were expounded.Next,taking CO and CH_(4) as examples,the liner correlation coefficients of absorbance and the temperature correction factors of the two indicator gases were calculated,and then the errors of concentration measurement for CO,CO_(2),CH_(4) and C_(2)H_(4) were further analyzed.The results disclose that the designed NDIR sensors can satisfy the requirements of industrial standards for monitoring the indicator gases for coal fire hazards.For the established NDIR-based monitoring system,the NDIRbased spectrum analyzer and its auxiliary equipment boast intrinsically safe and explosion-proof performances and can achieve real-time and in-situ detection of indicator gases when installed close to the coal fire risk area underground.Furthermore,a field application of the NDIR-based monitoring system in a coal mine shows that the NDIR-based spectrum analyzer has a permissible difference from the chromatography in measuring the concentrations of various indicator gases.Besides,the advantages of high accuracy,quick analysis and excellent security of the NDIR-based monitoring system have promoted its application in many coal mines.

Effects of caprock sealing capacities on coalbed methane preservation:Experimental investigation and case study

Caprocks play an important role in the trapping of coalbed methane(CBM)reservoirs.To study the sealing capacities of caprocks,five samples with different lithologies of Neogene clayrock,Paleogene redbeds,Permian sandstone,Permian mudstone and Permian siltstone were collected and tested using experimental methods of microstructure observation,pore structure measurement and diffusion properties determination.Results indicate that with denser structures,lower porosities,much more developed micropores/transition pores and higher pore/throat ratios,mudstone and siltstone have the more ideal sealing capacities for CBM preservation when comparing to other kinds of caprocks;the methane diffusion coefficients of mudstone/siltstone are about 6 times higher than sandstone and almost 90 times higher than clayrock/redbeds.To further estimate the CBM escape through caprocks,a one-dimensional CBM diffusion model is derived.Modeling calculation result demonstrates that under the same thickness,the CBM sealing abilities of mudstone/siltstone are almost 100 times higher than those of clayrock/redbeds,and nearly 17 times higher than sandstone,which indicates that the coal seam below caprocks like clayrock,redbeds or sandstone may suffer stronger CBM diffusion effect than that below mudstone or siltstone.Such conclusion is verified by the case study from III3 District,Xutuan Colliery,where the coal seam capped by Paleogene redbeds has a much lower CBM content than that capped by the Permian strata like mudstone,siltstone and sandstone.

利用野栽分离群体定位水稻粒型相关QTL

【目的】挖掘水稻粒型相关QTL位点可为水稻的粒型遗传机制研究和优质化分子育种提供理论基础。【方法】以广西普通野生稻高代自交系材料ZY03为父本,栽培稻品种日本晴为母本,通过常规杂交获得包含160个单株的F_2分离群体,并开展粒长、粒宽及粒长宽比等粒型性状的调查。利用分布于水稻12条染色体上的184个SSR标记对F_2群体单株进行分子检测。应用MAPMAKER EXP 3.0软件进行数据分析,构建分子标记连锁图。应用QTLmapping3.0软件,采用复合区间作图法(composite interval mapping,CIM),以LOD=2.5为阈值检测控制粒长、粒宽和粒长宽比等性状的QTL。【结果】在F_2群体中,目标性状呈现连续变异,有明显的双向超亲分离现象。共检测到与粒型相关的QTL 3个,其中1个粒长QTL位于第5染色体RM405~RM548区间内,被命名为qGL5.1,表型贡献率为10.68%,加性效应为0.02;在第1染色体RM5501~RM486区间内检测到1个控制粒宽的QTL,被命名为qGW1.1,表型贡献率为10.56%,加性效应为0.34;在第5号染色体RM405~RM548区间检测到1个控制粒长宽比的QTL,被命名为qLWR5.1,表型贡献率为14.77%,加性效应为0.12。上述所有QTL的增效等位基因均来自于亲本ZY03。其中,粒长QTL qGL5.1与粒长宽比QTL qLWR5.1位于同一标记区间内。【结论】从野栽分离群体挖掘到3个野生稻的粒型QTL位点,定位结果可用于下一步主效QTL的精细定位和分子标记辅助选择育种。