Effect of Microclimatic Modification on Growth and Yield of Sesame （Sesamum indicum L.） in a Semi-Desert Region of Northern Sudan

An investigation was carried out in the semi- desert region of northern Sudan, during 2000, to study the influence of different micrometeorological parameters on growth and yield of sesame under alley cropping system. Sesame, cv. Kenana-2, was grown in 6-m wide alleys formed by 3 year old Acacia ampliceps and Acacia stenophylla. Air temperature, relative humidity, wind speed, solar energy and shade behaviour were measured throughout the growing season. Irrigation was measured by water meter and soil moisture by gravimetric sampling at depths of 15, 30, 45 and 60 cm, in alley cropping and control plots. Sesame was evaluated for growth and yield performance in southern, central and northern parts of each alley. The results showed substantial reduction in wind runs, solar radiation and air temperature, while relative humidity was increased under alley conditions. Soil moisture content, especially in the upper 045 cm soil depth, was much higher in alley cropped plots than in the control plots. A. stenophylla resulted in the highest saving of irrigation water and considerably increased （40%） sesame seed yield. In contrast, sesame seed yield was reduced by 46% under A. ampliceps-alley cropping. Competition for light and water were highly responsible for variation in sesame seed yield in the different zones of the alley. A. stenophylla tree is, therefore, recommended in an alley cropping system in the semi-desert region of northern Sudan for its superiority in optimizing radiation and saving of irrigation water.

Production and achievements of Sesamum indicum industry in the world:Past and current state

Sesame production is important in agriculture,food industry,and the crop diversity due to its rich nutritional profile and health benefits.Despite its significant value,sesame is still an orphan crop that has received little scientific attention,resulting in low yield compared to other major oilseed crops.This review offers a comprehensive overview of the present state of production,knowledge,and research advancements concerning Sesamum indicum on a global scale.The FAOSTAT database was extensively used to examine the global trends from 1961 to 2021.In the past 60 years,global sesame production has substantially increased,with Asia and Africa being the primary producers.The integration of omics technologies and biotechnological interventions has revolutionized our understanding of the genetic basis of sesame,enhanced productivity,invigorated stress resilience,and improved seed quality.High-throughput sequencing methods such as RNA-seq,RAD-seq,SLAF-seq,and GBS technology are used in various studies,linkage mapping,and identification of trait-associated markers.Fine linkage maps,and multi-omics studies such as genomics,proteomics,transcriptomics,and metabolomics have been employed in sesame research for gene and QTL mapping.Proteins and metabolic pathways related to oil content,yield,and stress tolerance were reported.Genes and QTLs related to yield and its components,drought,salt,and osmotic stress tolerance were discovered.Candidate genes associated with capsule shattering and seed shattering were recently revealed.For more achievement in sesame,it is important to enhance sesame production efficiency through mechanization,advanced agricultural practices,and knowledge dissemination to farmers.MAS and multi-omics integration should be particularly reinforced.The advancements in sesame production present a significant and promising opportunity for farmers,governments,and stakeholders in the agricultural sector.

Deletion of a 1,049 bp sequence from the 5′UTR upstream of the SiHEC3 gene induces a seed non-shattering mutation in sesame

Sesame is a labor intensive crop with limited mechanized harvesting mainly due to the seed shattering(SS)trait.In this study,we performed a genetic analysis of the seed-shattering resistance(SR)trait with a SR sesame mutant 12M07.Unlike the SS type,the parenchyma cells in the abscission zone of the 12M07 mutant are arranged loosely but adhere to the seed coat.Inheritance analysis of six generations derived from 12M07(SR)×Xiangcheng Dazibai(SS)showed that the SR trait is recessive and controlled by a single gene pair.Association mapping of the F2population with 888,619 variants(single-nucleotide polymorphisms(SNPs)and insertion-deletion(InDels))and 31,884 structural variations(SVs)determined that only SV12002 in the 5′upstream region of gene Sindi0765000(named SiHEC3)in Chr.3 was significantly associated with the SR trait.SiHEC3 encodes the bHLH transcription factor.A 1,049 bp deletion occurred in the 5′UTR of Sihec3 in 12M07.SiHEC3 is mainly expressed in developing placental tissues,with the expression peaking in capsules at 45 days after pollination.A dual-luciferase reporter assay in tobacco confirmed that the promoter activity of Sihec3 was reduced because of the deletion of the 1,049 bp promoter sequence.Protein–protein interaction network analysis showed that HEC3 is co-expressed with nine key proteins,such as SHATTERPROOF1(SHP1)and SEEDSTICK(STK)which participate in the secondary wall biosynthesis of the abscission layer in plants.The findings of this study show the important function of Sihec3corresponding with the SR trait and supply the genetic information for breeding new varieties that are amenable to mechanized harvesting in sesame and other crops.

Combined Effects of Compost,Supraxone and Lambda-Super on Soil Microbial Activity under Pluvial Cultivation of Sesame(Sesamum indicum L.)in Burkina Faso

Sesame cultivation is strategic for the economy of Burkina Faso. Indeed, after cotton, sesame is the second most important agricultural product for exportation. However, its production is limited by plant diseases and pest attacks. Facing this situation, large amounts of pesticides are used to boost productivity. But, these chemicals have a negative impact on soil fertility. In this instance, the effects of Supraxone and Lambda-super in the presence of compost on soil microbial activity under rainfed sesame cultivation in a peasant environment were studied. The experiment design was a block of Fisher (BCR) comparing the non-treated parcel (TNT) to the parcel amended only with compost (C) and to the parcel amended with compost and treated with the pesticides (C + P), respectively. Soil samples were taken at depths of 0 - 20 cm before sowing at 41st and 81st days after sowing. Respiratory activity and soil microbial biomass were monitored respectively by respirometric tests and by the fumigation-incubation method. The results show that the addition of compost into the soil with or without supraxone treatment and Lambda-super resulted in an increase in microbial biomass and soil respiratory quotient. These results show that the provision of compost in sufficient quantity corrects the inhibitory effect of soil biological activity by pesticides.

Genetic Diversity Assessment of Moroccan Sesame(Sesamum indicum L.)Populations Using Agro-morphological Traits

Genetic diversity of Moroccan sesame(Sesamum indicum L.)was analyzed for the first time using agro-morphological traits.Thirty-three sesame populations collected from Tadla region in Morocco were evaluated for 13 parameters in three contrasted environments,Afr-13,Afr-14 and Atj-14.Broad and significant variation among populations was observed only for three agro-morphologic traits,namely first capsule height(FCH),number of seeds per capsule(NSC)and thousand seeds weight(TSW).The respective overall averages were 71.82 cm(ranging from 65 cm to 77 cm),61.39(varying from 57 to 65)and 3.20 g(ranging from 3.0 g to 3.4 g).Environment had a highly significant effect on all studied parameters,except capsule size and oil content.The obtained mean values of parameters studied showed that environment Afr-14 was the most favorable for most of them,particularly seed yield(1.32 t/ha)and TSW(3.57 g).Significant and interesting correlations were observed between seed yield per plant(SYP)and other parameters.As relevant implication of this finding,number of capsules per plant(NCP)and NSC could be used as valuable selection criteria in sesame breeding program.However,limited and non-significant variation among sesame populations for most of parameters studied suggests that they are genetically very close and may be derived from a single cultivar or germplasm.Molecular characterization is needed to confirm or refute this hypothesis.Besides,when compared with sesame grown throughout the world,Moroccan sesame was found to be very promising,which open up the possibility to develop this crop in this country.

Analysis on Genetic Diversity and Genetic Basis of the Main Sesame Cultivars Released in China

SRAP （sequence-related amplified polymorphism） was used for the analysis of 67 sesame （Sesamum indicum L.） cultivars widely used in Chinese sesame major production areas from 1950 to 2007. A total of 561 bands were amplified using 21 SRAP random primer pairs, with 265 of them were polymorphic, resulting in a polymorphism ratio of 47.2%. The total bands and polymorphism amplified by each primer pair averaged 26.7 and 12.6, respectively. The average genetic similar coefficient and genetic distance of the 67 cultivars were 0.9104 and 0.0706, respectively, indicating limited genetic diversity and narrow genetic basis. Comparative analysis on genetic similarity and genetic distance of different classified cultivars showed that the difference of average genetic similarity coefficient and genetic distance between the landraces and cultivars bred through crosses reached significant levels （P=0.01）, with the genetic basis of landraces wider than that bred cultivars. The genetic basis of cultivars used in 1990-2007 was more narrow than that of cultivars from 1950 to 1969 and from 1970 to 1989, with the differences of average genetic similarity coefficient and genetic distance reached 0.01 significant level. The genetic basis of Chinese sesame main cultivars is relatively narrow, and the genetic basis of cultivars developed through crosses in recent years is narrower than history cultivars.

Triple test cross analysis for seed yield and its components in sesame under water stress conditions

Water deficit is a limiting factor in sesame cultivars yield,thus identification of genetic mechanisms of sesame traits under water stress conditions is essential to development of water stress tolerant genotypes.Hence,the triple test cross(TTC)analysis in F_(2) population of the sesame cross(NA_(76)NA_(54))was used.Since,30 TTC families with their 13 respective parents were evaluated during the summer season 2020 under two irrigation treatments.i.e.,normal irrigation with 5952.38 m^(3) hm^(-2) of applied water,and water stress with 2976.19 m^(3) hm^(-2) of applied water.This was implemented at the experimental field of Kafr El Hamam/Sharkia,Agricultural Research Station,Agricultural Research Center(ARC),Egypt.Additive(D)and dominance(H)gene actions as well as epistatic and its two components of additiveadditive,additivedominance plus dominancedominance were involved in the inheritance of all studied traits under both irrigation treatments and their combined analysis.The degree of dominance(H/D)^(0.5) verified the presence of partial dominance in most cases.The correlation coefficient between sums(additive)and differences(dominance)was non-significant,showing that dominant genes between lines were ambidirectional.The moderately water stress tolerant TTC families as the best selected families were found in families 22,25,10,12,and 15.Therefore,postponing selection in these selected families to later segregating generations for all studied traits would be effective to exploit the positive effects of additiveadditive epistasis.

芝麻栽培种与野生种(Sesamum schinzianum Asch、Sesamum radiatum Schum & Thonn)种间杂交后代的生物学特性

【目的】探明芝麻栽培种与野生种种间杂交的亲和性,分析杂交后代遗传特征。【方法】以26个基因型(Sesamum indicum L.)与刚果野芝麻(Sesamum schinzianum Asch)和野芝1号(Sesamum radiatum Schum&Thonn)野生种为杂交亲本,借助胚培养技术获得种间杂交后代。采用SSR标记和生物学方法鉴定并分析杂交种F1的遗传特性。【结果】通过胚培养技术获得2 430个种间杂交F1株系,对部分材料的检测表明杂种阳性率为95.83%。刚果野芝麻×栽培种的正反交杂交率分别为34.62%(A)和11.54%(C),野芝1号×栽培种的正反交杂交率分别为100%(B)和19.23%(D)。F1花粉粒存在部分不育和高度不育两种类型,F1自交结实率分别为2.32—2.57粒/蒴果(S.schinzianum×S.indicum)和0.30—2.45粒/蒴果(S.radiatum×S.indicum)。【结论】S.radiatum与栽培种的杂交亲和率高于S.schinzianum。以野生种为母本与栽培种杂交,杂交种F1在株高、根系结构等性状方面超亲表现明显;株系高抗枯萎病;部分F1株系有低自交结实性。

Association Analysis for Quality Traits in a Diverse Panel of Chinese Sesame(Sesamum indicum L.)Germplasm

The main objective of this study was to evaluate the potential of a sesame （Sesamum indicum L.） panel for association analysis, and investigate the genetic basis of oil content （OC）, protein content, oleic acid concentration, and linoleic acid concentration using association mapping. A panel of 216 sesame accessions was phenotyped in a multi-environment trial and fingerprinted with 608 polymorphic loci produced by 79 primers, including simple sequence repeats （SSRs）, sequence-related amplified polymorphisms （SRAPs）, and amplified fragment length polymorphisms （AFLPs）. Population structure analysis revealed two subgroups in the population. The Q model performed better for its ability to re-identify associations for the four traits at highly significant P-values compared to the other three mixed models. And a total of 35 and 25 associations for the four traits in 2010 and 2011 were identified, respectively, with the Q model after Bonferroni correction. Among those associations, only one for OC was re-identified in two environments, and several markers associated simultaneously with multiple traits were discovered. These results suggest the power and stability of the Q model for association analysis of nutritional traits in this sesame panel for its slight population stratification and familial relationship, which could aid in dissecting complex traits, and could help to develop strategies for improving nutritional quality.

芝麻耐湿性QTL定位及优异耐湿基因资源挖掘

【目的】芝麻是对湿害极其敏感的作物,湿害是影响中国芝麻生产发展和单产提高的主要障碍因素,然而,芝麻耐湿性分子生物学研究基础薄弱,迄今,国内外有关芝麻耐湿性基因定位的研究尚未见报道。利用重组自交系(RIL)群体进行芝麻耐湿性QTL定位,结合芝麻核心种质群体进行耐湿性相关分子标记研究,并挖掘优异耐湿基因资源。【方法】以高耐湿芝麻品种中芝13与极敏感种质宜阳白杂交后连续自交6代构建206个株系的RIL群体。利用113对多态性分子标记扫描RIL群体获得基因型数据,用MapMaker/EXP.3.0软件构建遗传连锁图谱。2009年和2010年在武汉和鄂州2地点通过人工淹水胁迫获得RIL群体盛花期湿害后正常株率和存活株率的表型数据,用Microsoft Excel 2010软件进行表型数据方差分析,用QTLNetwork 2.0软件基于复合区间作图法进行QTL定位,利用主效QTL紧密连锁的分子标记扫描核心种质群体,并结合耐湿性表型数据分析得到相关有效分子标记。通过盛花期耐湿性表型重复鉴定筛选,结合分子标记辅助选择,获得优异耐湿基因资源。【结果】构建的遗传连锁图谱全长592.4 cM,共有70个标记位点进入15个连锁群,标记间的平均距离为8.46 cM。共检测到与盛花期耐湿性相关的6个QTL位点,定位在第7、9、13和15连锁群上,分别解释5.67%—17.19%的表型变异,加性效应值2.7190—9.7302,贡献率最大的QTL为qWH10CHL09,加性效应3.9394,其增效等位基因来源于母本中芝13,SSR标记ZM428与其紧密连锁(遗传距离为0.7 cM)。标记ZM428在186份芝麻核心种质中验证结果表明,该标记2种基因型的资源间在耐湿表型上存在显著差异(P=0.0163),因此,标记ZM428可作为芝麻耐湿性分子辅助选择的有效标记。还挖掘出8份优异耐湿基因资源,湿害后其正常株率均>70%,存活株率均>80%。【结论】检测到6个芝麻耐湿性相关QTL,其中,贡献率最大的17.19%,获得1个有效分子标记,挖掘出8份优异耐湿基因资源。

芽期Al^(3+)胁迫对芝麻幼苗生长的影响及种质资源耐铝毒性评价

铝毒害是影响江西省红壤作物生长的重要因素之一,为了解铝对芝麻生长的毒害,发掘耐铝毒种质资源,用Al2(SO4)3·18H2O溶液模拟发芽期Al3+胁迫研究不同浓度Al3+对芝麻品种赣芝9号和赣芝12成苗及幼苗生长的影响。结果表明,Al3+浓度在0~100mg/L时,随着Al3+浓度的增加,成苗率、芽长、根长和苗鲜重均不断下降,且根长下降最为明显;而浓度在250~1 000mg/L时,芝麻难以成苗。Al3+浓度在50mg/L时,成苗率、芽长、根长和苗鲜重等测定指标均急剧下降,因此可认为50mg/L的Al3+浓度胁迫可以作为芝麻种质耐铝毒性筛选鉴定的参考浓度。进而在50mg/L Al3+胁迫下评价96份芝麻种质[含39个改良品种(系)和57份地方种质],可将它们聚为3类,即包含21份耐铝毒种质、37份中等耐铝毒种质和38份不耐铝毒种质;发掘出赣芝9号、金黄麻、武宁黑等21份耐铝毒种质。比较分析表明,地方种质资源的平均耐铝毒特性要优于改良品种(系),且除成苗率外,地方种质耐铝毒性的其他指标的变异系数和多样性指数均大于改良品种(系)。

Biological effects of low-energy C ion implantation on sesame(Sesamum indicum L.)

Field cultivation experiments on white sesame(Sesamum indicum L.)seeds implanted with low-energy C ion showed that different dosages of C ion implantation pro-duce different biological effects.Sesame plants in 6 different dosage groups with C ion density respectively at 1×10^(11),1×10^(12),1×10^(15),5×10^(15),1×10^(16),5×10^(16)ion/cm2 were superior to the control group in plant height,leaf number,stalk diameter and leaf size.Further,sesame plants in these groups flower and seed earlier than those in the control group,and single plant yield also increased.Of all the groups,the 5×10^(15)ion/cm2 dosage group yielded the best effect,whereas the 1×10^(17)/cm^(2)dosage group showed an evident inhibitory effect of ion implantation on the germination and growth of the sesame seeds.

C_(18)净化-HPLC测定芝麻中芝麻素和芝麻林素含量

采用HPLC测定芝麻中芝麻素和芝麻林素含量,对超声波提取芝麻中芝麻素和芝麻林素的条件进行了研究,同时探讨了提取液净化处理对其测定结果的影响。通过单因素及正交试验,确定超声波最佳提取条件为:提取剂V(正己烷)/V(甲醇)=60∶40,液料比30∶1,超声提取温度65℃,超声提取时间12 min。采用C18对样品进行净化处理,可提高净化效果,减少测定干扰。

芝麻苗期干旱生理生化指标响应特征及其基因表达分析

为建立芝麻抗旱性快速鉴定体系及筛选芝麻抗旱品种,采用盆栽反复干旱法,设置正常水分(CK)和干旱胁迫(DS)两种处理,对31份芝麻材料进行生理生化指标测定和综合评价,同时利用qRT-PCR检测SOD合成相关基因的表达量。结果表明:芝麻苗期■、可溶性糖(SS)、脯氨酸(Pro)含量和超氧化物歧化酶(SOD)、过氧化物酶(POD)活性与CK相比均显著上升,各指标综合抗旱系数和抗旱指数的变异系数最高的分别是SOD(98.64%)和■(154.01%);抗旱指数与■含量、SOD活性呈极显著正相关关系,这两个指标可作为芝麻苗期抗旱性鉴定的重要指标。聚类分析将31份芝麻材料划分为5类抗旱类型,分别为高抗型、中抗型、低抗型、低感型和高感型。利用综合评价方法,筛选出高抗材料2份(‘汾芝10号’和‘豫-11-1’),中抗旱材料4份,低抗旱材料9份,敏感材料10份,高感材料5份;筛选出■含量和SOD活性可作为芝麻种质资源苗期抗旱特性快速鉴定的指标。

钾营养对花期干旱胁迫芝麻生长及叶片氮代谢的影响

为探究花期干旱胁迫下不同钾肥水平对芝麻(Sesamum indicum L.)生长和叶片氮代谢的影响,以及芝麻响应干旱胁迫的生理机制,以赣芝7号为试验材料,采用盆栽控水试验方法,设置3个钾肥水平(0、60、120 kg·hm^(-2);K_(2)O)和2个土壤水分处理(75%±5%和45%±5%田间持水量),对比不同钾肥水平下芝麻生长、氨基酸、可溶性蛋白含量、氮代谢酶活性等指标的差异。结果表明,干旱胁迫严重抑制芝麻生长,与正常灌水相比,干旱处理芝麻叶片相对含水量、株高、比叶重和叶绿素值分别平均下降8.2个百分点、23.5%、8.1%和6.6%。干旱导致芝麻叶片的氮代谢能力减弱,与正常灌水相比,干旱处理芝麻叶片的氮、钾、可溶性蛋白(SP)和氨基酸(AA)含量分别平均提高5.4%、10.6%、21.1%和52.7%,硝酸还原酶(NR)和谷氨酸合成酶(GOGAT)活性分别平均下降11.3%和16.6%。干旱胁迫下,与不施钾相比,施钾使芝麻叶片相对含水量、株高、比叶重、叶绿素值、钾、氮含量分别提高3.3~7.2个百分点、20.9%~39.0%、3.2%~5.5%、1.0%~4.5%、14.8%~19.6%、2.0%~5.4%;硝酸还原酶和谷氨酸合成酶活性分别提高8.7%~9.5%和15.1%~20.0%。相关性分析表明,干旱胁迫下,叶片钾含量与氮、SP、FAA含量及NR、GOGAT活性呈显著或极显著正相关(R^(2)=0.69~0.95)。综上所述,施钾可缓解干旱胁迫对芝麻造成的不利影响,提高叶片钾、氮含量及硝酸还原酶和谷氨酸合成酶活性;施钾主要通过调控渗透调节、蛋白质合成及氮代谢等途径来提高芝麻的耐旱性。本研究结果为芝麻抗旱栽培提供了科学依据。

隐性核不育芝麻AFLP反应体系的优化

以芝麻细胞核雄性不育系95ms-5为材料,对AFLP反应体系中的酶切连接、预扩增和选择性扩增中的关键性因素进行了优化。结果表明,在模板DNA质量浓度为200ng/μL、37℃酶切连接6h的情况下,预扩增中最佳Mg2+浓度为1.0mmol/L,dNTP最佳浓度为0.3mmol/L,Taq酶量以0.5U为宜,预扩增引物终浓度为0.4mmol/L;选择性扩增中,预扩增产物稀释10倍后,以Mg2+0.8mmol/L、dNTP 0.2mmol/L、Taq酶1.0U、选扩引物0.6mmol/L为宜。

不同播期对胡麻生长发育及产量的影响

白银市胡麻生产现已基本实现良种普及,但与之相配套的高产栽培技术试验及推广相对滞后。为了充分挖掘胡麻新品种的增产潜力,以白银市当前主栽胡麻品种陇亚10号、定亚24号、陇亚13号为试材,研究了不同播期对胡麻生长发育及产量的影响。结果表明,播期对胡麻生长发育影响显著,生育期随着播期的延后而缩短,生育进程则加快,播期每推迟7 d,生育期则缩短3耀4 d。播期延后对胡麻出苗率、株高、单株分茎数、主茎分枝数、单株果数、单株粒重等主要农艺性状影响较大,且均呈现先增后减的趋势,而对蒴果大小、千粒重影响则不显著。不同播期处理对胡麻品种的折合产量影响显著,陇亚10号、定亚24号、陇亚13号的折合产量均以3月24日播期处理最高,分别为2493.3、2533.3、2433.3 kg/hm^(2)。综合考虑认为,陇亚10号最适播期为3月24—31日,陇亚13号最适播期为3月17—24日,定亚24号最适播期为3月24日。

三种除草剂防除芝麻田杂草的效果及安全性评价

为筛选出高效安全的芝麻(Sesamum indicum L.)苗后茎叶除草剂,选择48%灭草松水剂、15%精喹禾灵乳油和108 g/L高效氟吡甲禾灵乳油3种除草剂进行田间施药试验。结果表明,15%精喹禾灵乳油和108 g/L高效氟吡甲禾灵乳油对芝麻田马唐[Digitaria sanguinalis(L.)Scop.]、稗草[Echinochloa crusgalli(L.)Beauv]和狗尾草[Setaria viridis(L.)Beauv.]3种禾本科杂草防除效果均达100.0%,但对莎草科香附子(Cyperus rotundus L.)和苋科空心莲子草[Alternanthera philoxeroides(Mart.)Griseb.]防除效果较差;48%灭草松水剂对香附子和空心莲子草防除效果好,但是安全性差。综合考虑防效、产量以及安全性,15%精喹禾灵乳油和108 g/L高效氟吡甲禾灵乳油可用于芝麻田苗后除草。

芝麻EST-SSR标记的开发和初步研究

为加速分子标记在芝麻研究中的应用,利用网上现有的芝麻EST(expressed sequencetags)数据信息,开展了芝麻EST-SSR功能性标记的开发和利用研究。在所有的3328条芝麻EST序列中共确认得到1785条非冗余EST序列。其中,在含有微卫星重复的148条序列中共检测有155个EST-SSR。非冗余EST序列总长为774.27kb,平均每4.99kb含有一个EST-SSR。EST-SSR的分布频率和特征分析表明,以AG/TC为重复基元(motif)的SSR出现最多,占总SSR的37.42%。利用这些序列,设计开发了50对EST-SSR引物,并分别选用36个芝麻、2个棉花、2个大豆和2个油葵进行多态性和通用性研究。其中44对引物在供试芝麻材料中扩增出条带,共产生108个位点,平均每对引物产生2.45个位点,多态信息含量(polymorphism information content,PIC)平均值为0.390。根据遗传相似性系数进行聚类,有26个芝麻材料聚类在两个大的亚类(III和IV)中,聚类结果表明芝麻的基因型与地理来源之间没有必然的联系。此外,分别有2对、3对和4对引物可以在棉花、大豆和油葵中进行通用性扩增。本研究证实这种全新开发的芝麻EST-SSR标记在芝麻遗传多样性分析、遗传图谱构建以及比较基因组等研究方面有广阔的利用前景。

铵硝配比对不同芝麻品种苗期生长及养分吸收的影响

为了解芝麻苗期生长对氮素形态和配比的要求,明确芝麻氮肥施用适宜的铵硝比,以长江流域主栽芝麻品种中芝13和黄淮流域主栽芝麻品种漯12为材料,采用室外营养液培养方式,根据铵态氮(NH_4^+-N)和硝态氮(NO_3^--N)摩尔浓度比例的不同设置7个处理(10∶0、9∶1、3∶1、1∶1、1∶3、1∶9、0∶10),定期测定和分析营养液p H值、植株生物量、根系形态参数、地上部和根部养分(N、P、K、Ca、Mg)浓度、游离NH_4^+-N和NO_3^--N浓度等。结果表明:高比例NH_4^+-N处理(10∶0、9∶1和3∶1)显著抑制了芝麻苗期生长,主要表现为植株矮小、叶片枯焦、根系粗短,甚至死亡,随着NH_4^+-N比例的增加,抑制程度越明显。两个芝麻品种对NH_4^+毒害的耐受能力不同,中芝13更耐受NH_4^+毒害。铵硝配比1∶9时,两个芝麻品种植株生物量达到最大值,根系最为发达,根际p H值维持在适宜的范围内;其中,中芝13整株干重、总根长和根系总表面积较完全NO_3^--N处理(0∶10)分别显著增加了47%、29%和15%,植株地上部和根系N、P、K浓度较完全NO_3^--N处理分别增加了5%、17%、9%和10%、32%、13%;铵硝配比1∶9对漯12的生物量及养分吸收利用与完全NO_3^--N处理相比没有显著差异。因此,适当加入铵态氮可以提高芝麻苗期生物量,促进根系的生长,铵硝比为1∶9较适合芝麻幼苗的生长及养分的吸收。在芝麻田间氮素施肥中,建议以NO_3^--N为主,同时根据芝麻品种特性及土壤供氮等条件合理配施NH_4^+-N。