The application of selenium (Se) can promote the growth of potatoes and increase the Se content of potato tubers. Nitrogen (N) can promote nutrient absorption and potato yield. However, the effects of Se and N on the yield and Se content of potato tubers have not been reported. Field experiments were conducted in 2019–2020 and 2020–2021. Three N levels, i.e., 0 kg N ha−1 (N0), 150 kg N ha−1 (N1) and 200 kg N ha−1 (N2), and three Se levels, i.e., 0 g Se ha−1 (Se0), 500 g Se ha−1 (Se1) and 1000 g Se ha−1 (Se2), were set up. Potato yield, root dry weight, root activity, leaf area index (LAI), net photosynthetic rate (Pn), malondialdehyde (MDA) content, antioxidant enzyme activity and Se content were investigated. N application increased root dry weight and activity, LAI, antioxidant enzymes activities, Se content and decreased MDA content. Pn, total potato yield and commercial potato yield first increased and then decreased with the increase in N application level. Se application increased root activity, Pn, antioxidant enzyme activities, total yield, commercial potato yield, commercial potato rate, Se content and decreased MDA content. In general, compared with the single application, the combination of N and Se fertilizers further promoted the growth of potatoes, increased the yield of potatoes and the Se content of potato pieces.

Prevalent irregular rainfall, flooding for weed control, and unleveled fields in the middle and lower reaches of the Yangtze River all contribute to flooding stress on germination and growth of direct-seeded rice (Oryza sativa L.). Herein, some experiments were conducted so as to assess the effects of seed priming with selenium (Se) on the germination and growth of rice under hypoxia. The experiment was arranged in a completely randomized factorial design with two factors and five replicates. Factors included Se concentration (0, 30, and 60 μmol/L) and duration of flooding stress (0, 2, 4, and 8 days). The experimental results showed that Se accelerated seed germination and increased emergence index and final emergence percentage. Additionally, Se increased shoot and root lengths and dry weights, but high Se concentration (60 μmol/L) reduced 18-day-old seedling dry weight under long-term flooding (8 days). Furthermore, Se reduced malondialdehyde content and increased starch hydrolysis efficiency in seeds, superoxide dismutase, peroxidase, catalase, and glutathione peroxidase activities and seedling soluble protein and total chlorophyll contents. Se improved seedling total Se and organic Se contents while increasing total dry weight and yield. Notably, the highest yield was obtained after a 4-day flooding period. Although Se priming favored rice seedling emergence and growth under flooding conditions, Se concentrations equal or above 60 μmol/L increased the risk of seedling death during long-term flooding (≥8 days).

为研究不同栽培措施对江汉平原中稻的影响,采用L9(34)正交试验设计,对中稻"黄华占"连续两年采用播种期、施氮量、基本苗、水层进行不同栽培因素组合试验,探索不同栽培措施对中稻"黄华占"生长和产量的影响.结果表明,播种期和施氮量能显著影响生育期,播种期每推迟1期生育期缩短1.7～2d,施氮量每增加50kg/hm2生育期延长0.3～2d;施氮量与基本苗对产量关系密切,施氮量为150kg/hm2和移栽的基本苗60×104株/hm2时产量最高,平均达到8898.30kg/hm2;施氮量与基本苗主要通过影响单位面积有效穗进而影响产量,单位面积有效穗与产量呈显著正相关(R2=0.6859,P＜0.05).综合考虑,"黄华占"最佳的栽培因素组合为播种期4月25日,施氮量纯N 150kg/hm2,基本苗60×104株/hm2,移栽后7d内统一灌水5cm.

Nitrogen fertilizer and planting density are key factors affecting rice yield and nitrogen utilization efficiency. There is still a need to optimize nitrogen fertilizer and planting density management for high yield. We studied the effects of different quantities of nitrogen application (N0 0 kg ha−1, N1 120 kg ha−1, N2 180 kg ha−1) and planting density (low-density: 18.8 hills m−2; high-density: 37.5 hills m−2) on rice yield, photosynthetic characteristics, antioxidant system, and nitrogen use efficiency. ANOVA results indicated that most tested traits were affected by environment, planting density, N application, and their interactions. Comparing the results of low-density planting, high-density planting increased the panicle number by 21.12% but decreased the grain number per panicle and yield by 3.97% and 22.48%, respectively. Similarly, the superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) activities and PFPn (partial factor productivity of nitrogen) decreased by 8.20%, 6.99%, 16.41%, 14.28%, and 5.73%, respectively, while HIn (N harvest index) increased by 1.32%. Compared to no N application, N application treatments increased the panicle number, grain number per panicle, and yield by 9.92%, 17.64%, and 37.83% in the N1 treatment; and increased by 17.15%, 29.09%, and 128.94% in the N2 treatment, respectively. N application significantly increased net photosynthetic rates and enzyme activities of antioxidant antioxidases. Compared with N1, N2 decreased REn (apparent recovery efficiency of N), AEn (agronomic N use efficiency), and PFPn by 8.98%, 11.80%, and 25.14%, respectively, while, compared with N0, N1 increased HIn by 8.50%. It was observed that nitrogen fertilizer and planting density had an interaction effect on the net photosynthetic rate, antioxidant enzyme activities, and PFPn and HIn. Given a comprehensive consideration, it is best to apply nitrogen at a rate of 120 kg ha−1 at the planting density of 37.5 hills m−2 for high grain yield and high N use efficiency in our experimental site.

High selenium (Se) and low cadmium (Cd) and arsenic (As) contents in rice grains were good for human health. The genetic basis and relationship of Se, Cd and As concentrations in rice grains are still largely unknown. In the present study, large variations were observed in Se, Cd and As concentrations in brown and milled rice in normal and Se treatment conditions in 307 rice accessions from 3K Rice Genomes Project. Se fertilizer treatment greatly increased Se concentrations but had no obvious changes in concentrations of Cd and As both in brown and milled rice. Total of 237 QTL were identified for Se, Cd and As concentrations in brown and milled rice in normal and Se treatment conditions as well as ratio of concentrations under Se treatment to normal conditions. Only 19 QTL (13.4%) were mapped for concentrations of Se and Cd, Se and As, and Se, Cd and As in the same or adjacent regions, indicating that most Se concentration QTL are independent of Cd and As concentration QTL. Forty-three favorable alleles were identified for 40 candidate genes by gene-based association study and haplotype analysis in 14 important QTL regions. Se-enriched rice variety will be developed by pyramiding favorable alleles at different Se QTL and excluding undesirable alleles at Cd and As QTL, or combining favorable alleles at Se QTL with the alleles at Se-sensitive QTL by marker-assisted selection.

对巴东县野三关镇12个采样点进行调查,研究大蒜(Allium sativum L.)样品的土壤及其大蒜各部位的富硒性.结果 表明,12个采样点的土壤、蒜瓣、蒜薹、蒜叶的硒含量分别为0.083～2.676 mg/kg、0.054～0.589 mg/kg、0.038～0.257 mg/k g、0.033～0.152 mg/kg;不同土壤采样点,大蒜的蒜瓣、蒜薹、蒜叶硒含量均有差异;每个处理的蒜瓣对硒的富集性最强,大蒜各部位对硒的富集性强弱表现为蒜瓣＞蒜薹＞蒜叶.

Both Si and Se are the nutrient elements which had significant effects on crop growth and development. However, the application of Si and Se fertilizer management in field production of fragrant rice (Oryza sativa L.) was rarely reported. The present study was conducted with the objective to explore the effects of Si and Se fertilizer on fragrant rice performance though a six-season field experiment. The Se rates were set at three levels: 0 g ha(-1) (Se0), 36 g ha(-1) (Se1), and 72 g ha(-1) (Se2). The SiO2 rates were set at three levels: 0 kg ha(-1) (Si0), 22.45 kg ha(-1) (Si1), and 45 kg ha(-1) (Si2). Compared with Si0Se0 treatment, Si and Se treatments significantly increased SPAD values and net photosynthetic rates of fragrant rice at tillering stage and heading stage. Higher grain yield, effectively panicle number and seed-setting rate were also recorded in Si1Se1, Si1Se2, Si2Se1, and Si2Se2 treatments than Si0Se0 treatment in each cropping season. Moreover, Si and Se fertilizer management significantly increased the grain 2-acetyl-1-pyrroline (2-AP, main component of fragrant rice aroma) concentrations and the Si2Se1 treatment produced the highest or equally highest grain 2-AP concentration in each cropping season.

水稻( Oryza sativa? L.)是亚洲主要粮食作物.我国是水稻原产地之一,种植历史悠久.武陵山区包括湖南、湖北、重庆、贵州、四川相邻的一些山地.该地是我国扶贫攻坚的重点地区,分布有一定数量的富硒地区,发展水稻富硒种植对于发展当地经济有着积极意义.硒是人体必须的营养元素,它具有增强人体免疫力、防癌抗癌、提高机体抗氧化等多种功能,对人体健康起着重要作用.由于土壤中的硒含量不均匀,仅靠水稻吸收土壤中的硒元素难以达到富硒标准,通过对叶片喷施硒源,使其在水稻植株体内转化为有机硒便成了一个应用范围较广的技术.达到富硒标准的稻谷用途更广,更受市场欢迎,比普通水稻增值20％～50％,发展前景可观.水稻富硒种植中应掌握以下技术环节.

Cadmium (Cd) is a toxic heavy metal which has been threatening food security worldwide. In the present study, two sets of reciprocal introgression lines were used to dissect the genetic basis of Cd tolerance at seedling stage. Although the two parents had no significantly difference on Cd tolerance, the introgression progenies showed large variations. A total of 15 main-QTL (M-QTL) and 53 digenic epistatic QTL pairs (E-QTL) were detected for plant height, leaf length, leaf width and root length under Cd stress condition, each explaining 2.48-31.55% of phenotypic variations. E-QTL had larger effects than M-QTL for most traits, suggesting that E-QTL was the main genetic component for Cd tolerance at seedling stage. No common QTL, either M-QTL or E-QTL, was identified independent of background, indicated that both M-QTL and E-QTL were highly sensitive to genetic background. Two pleiotropic QTL in the regions of 13.31-15.56 Mb on chromosome 2 and 7.34-7.59 Mb on chromosome 11 were detected in the two backgrounds respectively, and further validated their effects on three traits by two introgression lines, indicated that they were both genetic true. Our results will give valuable QTL for improving Cd tolerance at seedling stage by molecular breeding.

对14个粳稻品种(系)叶面分别喷施0.5、1、1.5、2、2.5g/667m2的亚硒酸钠,以清水作为对照,研究了叶面施硒对粳稻产量和稻米外观品质的影响.结果表明,施硒对供试粳稻品种有增产效应,施硒量在1.5～2g/667m2时,供试品种(系)的平均单产达到最高值;施硒对供试品种的外观品质有改良效应,施硒量为1g/667m2时,14个供试品种(系)平均的垩白度下降1.47个百分点,垩白粒率下降3.23个百分点,达到最低值;施硒对供试品种的外观品质的影响存在差异,浙粳165和扬家粳7972在施用叶面肥之后垩白度和垩白粒率均升高,其他各个品种在1g/667m2硒处理下垩白粒率平均下降4.10个百分点,垩白度平均下降1.89个百分点,其中常粳167施硒后垩白粒率平均下降17.87个百分点,垩白度平均下降5.07个百分点.

Rice nitrogen (N) uptake and yield formation depend on both applied N fertilizer and soil-derived N. In this study, we determined the effects of topsoil removal on the N uptake and yield formation of rice crop. Four rice varieties were grown in farmers' fields in Wuxue County, Hubei Province, China in 2016-2018 under the treatments of topsoil removal (TR) and control (CK). The TR treatment was established by desurfacing soil at about half of the topsoil depth (11 15 cm). Experiments were conducted in three adjacent fields in the three years and 100 kg N ha 1 was applied in all plots except for zero-N treatment in 2018. Averaged across years, N treatments, and varieties, topsoil removal reduced total N uptake by 27.8 %. The period from midtillering to panicle initiation had the highest daily N uptake from topsoil compared with other growing periods. During this growing period, the percentage of N uptake from topsoil to plant N uptake ranged from 54.2 to 62.4 % with an average value of 56.4 % across both zero-N and N-applied treatments. On average, topsoil removal reduced grain yield by 16.7 % and total dry biomass by 17.6 %. Among yield components, panicles m(-2) was mainly responsible for the yield reduction in TR. Furthermore, total dry biomass rather than harvest index explained the yield reduction in TR compared with CK. Our results suggest that topsoil provided substantial N to rice crop especially during the period from midtillering to panicle initiation for achieving higher grain yield through increased panicles m(-2) and biomass production.

Fragrant rice has excellent rice quality and considerable economic benefits. There are few reports on planting density and irrigation management on the yield and 2-acetyl-△1-pyrroline (2-AP) content of fragrant rice. In this study, 2 planting densities (3–4 and 6–7 seedlings hills −1 ) and 3 irrigations (farmers’ irrigation practice with mid-season drainage (FP), alternate wetting and drying irrigation (AWD) at the − 15 cm (AWD15), and − 25 cm (AWD25) threshold level for irrigation managements) were adopted to investigate the effects of planting density and irrigation management on growth, yield, 2-AP, synthetic precursors, and enzymes involved in 2-AP formation. The results showed that dry weight (DW), leaf area index (LAI), panicle number, and yield as well as the content of 2-AP, synthetic precursors, and enzymes activities involved in 2-AP biosynthesis increased in high-density. Compared with FP, AWD15 increases N concentration of leaves, LAI, net photosynthetic rate (Pn), seed setting rate, and 1000-grain weight, yet it has no effect on yield. Although AWD25 has a better effect on enhancing 2-AP, AWD25 reduces DW, LAI, Pn, yield, and yield components. Our results illustrated that 6–7 seedlings hills −1 and AWD15 are the superior water-saving methods for fragrant rice to increase the content of 2-AP and maintain yield.

水稻是我国主要粮食作物之一,也是重要的高产作物.我国水稻常年面积30189kha2,种植面积占谷物种植面积的30.3%,产量21212.9万吨,占谷物产量的34.8%.我国水稻种植区域分布很广,从南方的海南省到北方的黑龙江省,从东边的江苏省到西边的新疆维吾尔自治区,从平原、丘陵到海拔2000多米的高山地带,都有分布.进入春季之后,水稻生产也进入了大忙季节,备耕、播种、田间管理都逐步进入议事日程.从水稻的生理特点、产地气候与土壤等条件考虑,春季水稻生产应该注意如下问题.

长农优231是长江大学主要粮食作物产业化湖北省协同创新中心以不育系长农2A与早熟抗稻瘟病恢复系长恢31配组育成的早熟三系杂交中籼新组合.该组合具有米质优、抗稻瘟病、丰产性好、成熟期早、综合农艺性状优良等特点,2019年8月通过湖北省农作物品种审定委员会审定.

甘薯(Sweet potato)又名甜薯、地瓜、番薯、红薯,是旋花科甘薯属能形成块根的栽培种,一年生或多年生草质蔓性藤本植物,它在植物学上的正式名字叫甘薯.甘薯味道甜美,营养丰富,又易于消化,可供大量热能,非洲和亚洲的部分国家以甘薯为主食.甘薯原产于南美洲,16世纪由菲律宾和越南等地传入我国.目前我国各地均有栽培,尤以淮海平原、长江流域及东南沿海各省区栽种较多.

剑叶是水稻主要的源器官,剑叶大小与产量呈极显著的正相关,揭示剑叶大小和单株产量的遗传基础对于选育株型适宜的水稻高产品种具有重要意义.本研究以来源广泛、多样性丰富的1016份全球水稻核心种质资源为材料,在湖北荆州连续两年考察了种质资源的剑叶大小和单株产量.结果 显示,剑叶长、宽、面积和单株产量在两年变异丰富,受环境影响大;剑叶长、宽和面积与单株产量相关性程度较低,说明这些性状的遗传基础不同.利用4.8M高密度SNP基因型数据进行全基因组关联分析,共定位到31个影响水稻剑叶相关性状和单株产量的QTL,其中1个QTL(qFLW4)在两年均定位到,3个位点同时影响多个性状(qFLW4和qFLA4、qFLL6和qFLA6、qFLL10.1和qFLA10).结合候选区间单倍型分析和生物信息学分析,鉴定到7个候选基因和10个有利等位基因.研究结果为克隆水稻剑叶性状新基因和通过分子标记辅助选择配置不同剑叶相关基因塑造理想株型提供基因资源.

苗期冷害是一种影响水稻群体建成和生长发育的延迟性冷害,最终导致水稻减产.筛选苗期耐冷性强的种质资源可以为水稻耐冷育种提供亲本资源.本研究采用3 000份全球水稻核心种质资源中的1 542份在人工气候箱进行苗期耐冷鉴定及评价,以存活率为评价指标.发现种质资源苗期耐冷性变异非常丰富,筛选出存活率80％以上的苗期耐冷资源材料73份,其中籼稻9份,温带粳稻47份,热带粳稻4份,粳稻混合型8份,籼粳中间型和香稻类型各1份,籼粳混合型3份,Ⅺ-B、Ⅺ-2和亚热带粳稻中未筛选到苗期耐冷材料.耐冷材料主要集中在温带粳稻中,但亦有部分籼稻材料表现出较强的耐冷性.多数苗期耐冷资源材料的综合农艺性状较差,结合株高、生育期性状等筛选出14份半矮秆和生育期适中的强耐冷性材料,可作为水稻苗期耐冷育种亲本应用.对利用种质资源开展苗期耐冷基因挖掘和选育全生育期耐冷品种进行了讨论.本研究初步阐明了水稻耐冷种质资源的分布,为水稻耐冷育种提供了优异的供体亲本材料.

水稻产量的高低取决于源和库的大小及彼此间的协调程度.为了了解不同源库基因聚合后对产量及其相关性状的影响,本研究以4个已克隆的水稻源库基因NALlLT、GNP1TQ、Ghd7MH63和Ghd89311构建的不同遗传背景的近等基因系为材料,彼此杂交培育不同源库基因的F2分离群体,标记辅助筛选遗传背景近似的不同单基因及双基因纯合聚合单株,考察其F3家系的源、库及产量相关性状.结果 表明,不同基因聚合的产量效应差异较大,其中NAL1LT+Ghd7MH63、NAL1LT+Ghd89311和Ghd7MH63+Ghd89311这3种基因聚合方式表现出较明显的增产效应,聚合系的单株产量分别比高值亲本显著增加26.45％、45.47％和48.03％,表明这3种基因聚合对聚合系的产量性状具有正向协同作用.相反,另外3种聚合方式(NAL1LT+GNP1TQ、GNP1TQ+Ghd7MH63和GNP1TQ+Ghd89311)的聚合系的产量相关性状有增有减或基本与双亲持平,产量聚合效应不明显.研究认为,复杂性状的聚合育种必须首先开展基因间的产量聚合效应研究,明确不同基因的聚合效果,以确保聚合育种的事半功倍.本研究结果为分子聚合改良水稻源库性状提供了理论依据.

Grain shape is a very important goal in the rice breeding program nowadays. Underlying the genetic basis of grain shape would largely speed the breeding process. In the present study, a diverse panel of 1016 rice accessions from 70 countries and areas worldwide were evaluated for their grain shapes. There were large variations for all three grain shape traits, including grain length, grain width and length to width ratio, and they had significantly positive or negative correlations with each other. Besides, high positive correlations were found between two experimental years. Genome-wide association mapping strategy was conducted to identify QTL for grain shape using 509219 high quality SNP genotypes and grain shape traits. A total of 70 QTL were identified in all chromosomes. Among them, 16 QTL were found on chromosome 1, 2, 3, 5, 7, 9 and 11 expressed in both years. Eight genomic regions on chromosome 1, 3, 4, 5, 7 and 9 had pleiotropic effects on two or three traits. Four genomic regions on chromosome 3, 5, 6 and 7 were identified in both year and controlled more than two traits. Besides, 25 QTL on all chromosomes except chromosome 8, 10 and 12 had large effect on the traits. In conclusion, these results helped us better understand the genetic basis of rice grain shape and provide valuable gene resources for improving rice grain for desired shape. (C) 2020 Friends Science Publishers

为探究不同硒源叶面肥对棉花生长的影响,在花蕾期对中棉所65、中棉所76、晶华棉113、晶华棉116、中棉所71、锦红棉15等6个品种分别施用Na2 SeO4、生物有机硒和EDTA Se硒肥,设空白对照,观测施硒对棉花农艺性状的影响.结果 表明,施硒对棉花的各个性状影响不同,施用硒叶面肥对供试品种籽棉产量、单铃重影响显著,品种和施硒处理的交互作用对株高、单铃重和衣指存在显著影响(P≤0.05);硒叶面肥的使用对不同品种棉花的单铃重和单株结铃数影响有差异;中棉65和锦红棉15的单株结铃数在EDTA Se处理下最高,中棉76在Na2 SeO4处理下单株结铃数最高,而中棉71和晶华棉116在生物有机硒处理下单株结铃数最高,晶红棉113在施硒处理后单株结铃数均有显著下降,中棉65在生物有机硒处理下单铃重均值最高,其他各个品种在施硒处理后单铃重均值均有所下降;不同品种在施用硒叶面肥后籽棉产量变化不同,其中中棉71在Na2 SeO4处理下籽棉产量显著高于对照,其他各个品种籽棉产量虽有所增加但未达显著水准,说明不同品种对不同硒源叶面肥的敏感性不同;生物有机硒对棉花的籽棉产量有促进作用,但不同硒源叶面肥对棉花衣分的影响在年度试验中的结果并不一致.