Ethephon Effect on Peanut Seed Dormancy Release

Dormancy is undesirable character for the peanut seed(Arachis hypogeae).KK 84-7 and KK 6 varieties are characterized to the Virginia type and its dormant period has been one to two months after harvest.The recommendation for breaking peanut seed dormancy by the International Seed Testing Association(ISTA)rules is preheat at 40°C up to 168 h.The total germination test is 17 d,if breaking dormant seed is required.Effect of ethephon on peanut seed dormancy release was studied in this experiment to reduce the analysis time compared to preheat method.Both varieties of peanut seeds were directly mixed with 0.96%ethephon and preheated at 40°C for 168 h.Standard germinations were conducted for all treated and untreated seeds.Ethephon was the most beneficial to release dormant seed at fresh harvest that achieved 86%and 84%normal seedlings for KK 84-7 and KK 6,respectively.The normal seedlings of preheat treatment showed 75%for KK 84-7,and 66%for KK 6.Only 6%normal seedlings were observed in untreated seeds of KK 84-7 and 56%of KK 6.After storage at 20°C for 28 d,KK 84-7 had over 90%normal seedlings with both ethephon and preheat methods,but only 42%germination was observed in untreated seeds.In KK 6,the highest germination by 90%was found in ethephon,followed by untreated and preheated seeds that were 87%and 83%,respectively.The paired t test of normal seedlings between ethephon and preheat treatments demonstrated that the greater average germination was found in ethephon method for both varieties.This research suggests that ethephon is the advantageous method for breaking peanut seed dormancy.The germination test duration is more rapid,only 10 d,since preheat for 168 h is not necessary.

Use of Unmanned Aerial System (UAS) Phenotyping to Predict Pod and Seed Yield in Organic Peanuts

Peanut (Arachis hypogaea L.) is a highly nutritious food that is an excellent source of protein and is associated with increased coronary health, lower risk of type-2 diabetes, lower risk of breast cancer and a healthy profile of inflammatory biomarkers. The domestic demand for organic peanuts has significantly increased, requiring new breeding efforts to develop peanut varieties adapted to the organic farming system. The use of unmanned aerial system (UAS) has gained scientific attention because of the ability to generate high-throughput phenotypic data. However, it has not been fully investigated for phenotyping agronomic traits of organic peanuts. Peanuts are beneficial for cardio system protection and are widely used. Within the U.S., peanuts are grown in 11 states on roughly 600,000 hectares and averaging 4500 kg/ha. This study’s objective was to test the accuracy of UAS data in the phenotyping pod and seed yield of organic peanuts. UAS data was collected from a field plot with 20 Spanish peanut breeding lines on July 07, 2021 and September 27, 2021. The study was a randomized complete block design (RCBD) with 3 blocks. Twenty-five vegetation indices (VIs) were calculated. The analysis of variance showed significant genotypic effects on all 25 vegetation indices for both flights (p < 0.05). The vegetation index Red edge (RE) from the first flight was the most significantly correlated with both pod (r = 0.44) and seed yield (r = 0.64). These results can be used to further advance organic peanut breeding efforts with high-throughput data collection.

DOF transcription factors in developing peanut (<i>Arachis hypogaea</i>) seeds

DNA binding with one finger (DOF) transcription factors play important roles in storage material accumulation and morphogenesis of developing seeds. Oil and protein contents varied in different cultivars in important oil crop peanut. DOF proteins have not been studied in this crop. In this paper, we analyzed all the DOF genes expressed in developing seeds from a cDNA library with 20,000 transcripts, cloned and compared similar genes of GW391729 from eight peanut cultivars, and analyzed similar genes expressed in root and leave with control and inoculated with Ralstonia solanacearum. The results indicate that total eight types of DOF genes were expressed in developing seeds of cultivar 063103. Most of DOF transcription factors expressed involved in developmental process in a complicated way. Among them, GW391729 is possible related to the seed number in fruit, and also is possible related to leafspot resistance. Detailed function of these DOF proteins need to be further studied.

Identification of major QTL for seed number per pod on chromosome A05 of tetraploid peanut(Arachis hypogaea L.)

The inheritance of pod-and seed-number traits(PSNT) in peanut(Arachis hypogaea L.) is poorly understood. In the present study, a recombinant inbred line(RIL) population of 188 lines was used to map quantitative trait loci(QTL) for number of seeds per pod(NSP),number of pods per plant(NPP), and numbers of one-, two-, and three-seeded pods per plant(N1 PP, N2 PP, and N3 PP) in four environments. A total of 28 consensus QTL and 14 single QTL were identified, including 11 major and stable QTL. Four major and stable QTL including qN3 PPA5.2, q N3 PPA5.4, qN3 PPA5.5, and qN3 PPA5.7 each explained 12.3%–33.0% of phenotype variation. By use of another integrated linkage map for the A5 group(hereafter referred to as INT A5 group), QTL for PSNT were located in seven intervals of 0.73–9.68 Mb in length on chromosome A05, and candidate genes underlying N3 PP were suggested. These findings shed light on the genetic basis of PSNT. Major QTL for N3 PP could be used as candidates for further positional cloning.

Simple and Efficient Cultivation Technology for the Peanut under the Standardization Mode of Single-seed Sowing

Single-seed sowing is a new,simple and efficient cultivation mode for peanut that realized from cultivation of healthy individual and construction of high-yielding population. The cultivation mode has the obvious advantages in uniform seedling,strong sprouting,seed saving and cost saving,thus it is considered as one of the effective ways for high-yield and high-efficient peanut cultivation in China in the future.Through integrating with other high-efficiency and simple cultivation measures,the single-seed sowing technology system has made conforming to China's national standardization cultivations of peanut and the technology was already applied in the main producing areas of peanut and gained the significant efficiency and abroad application prospects. Based on many years of researches in single-seed sowing technology,high-efficiency fertilization and scientific chemical control in the research team,by combining with the latest research results in plant protection and machinery,this paper described the key points and matters needing attentions from variety selection,planting mode,rational fertilization,planting specifications and field management.

Research of Seed Testa Structure and Storage Material of Peanut Germplasm with Different Resistance to A. flavus

There was an obvious relationship between seed testa structure, storage material and resistance to A. flavus of peanut. Results showed that seed testa of peanut germplasm with high resistance （HR） to A. flavus infection had thicker wax layer, integrated and tight epidermis layer, regular vascular tissue range. However, the seed testa of peanut germplasm with high sensitivity （HS） to A. flavus had the reverse results, and results of those with medium resistance （MR） to A. flavus lay in between, but changes of testa thickness were not significant among different resistance kinds. Results also showed that some seed storage materials were closely related with resistance potential to A. flavus. It seemed that varieties with higher resistance to A. flavus had higher oleic acid and protein content, lower linoleic acid and fat content. Content of palm acid, total sugar and VE did not show positive relationship with the resistance to A. flavus.

种衣剂处理对低温胁迫下花生种子萌发及幼苗生长和生理特性的影响

花生播种期易受低温胁迫,为明确种衣剂处理对低温胁迫下花生种子萌发、幼苗生长和生理特性的影响,以常温(25℃)处理为对照(CK),设8℃和10℃两个低温胁迫处理,各温度下设种衣剂包衣和清水浸润对照两种处理方式,研究种衣剂处理对低温胁迫下花生种子活力、幼苗干物质积累、根系形态特征和光合生理的影响。结果表明,相对于常温处理,8℃低温胁迫处理显著降低了花生种子发芽势(5.9%)、发芽率(7.7%)、发芽指数(11.0%)、种子活力指数(6.9%)和幼苗叶片SPAD值(11.4%),同时对幼苗根系生长产生抑制作用,其根长、根表面积和根体积较25℃常温和10℃低温胁迫处理分别显著降低50.0%~50.2%、44.9%~48.1%、48.2%~48.5%,但8℃低温胁迫处理对花生幼苗地上部和地下部干物质积累、最大光化学效率及胞间二氧化碳浓度、气孔导度、净光合速率和蒸腾速率等光合参数均无显著影响;种衣剂处理显著提高了8℃低温胁迫下花生种子的发芽势(8.2%)、活力指数(10.9%)和花生幼苗根长(45.1%)及根表面积(38.4%),但对10℃低温胁迫和常温处理均无显著影响,同时,种衣剂处理还显著提高了常温处理下花生幼苗干物质积累、最大光化学效率和功能叶片光合特性以及10℃低温下地上部干物质积累和最大光化学效率,但对8℃低温胁迫无显著作用。综上,花生种子萌发和幼苗根系生长对低温胁迫的响应更加显著,而种衣剂处理可以通过改善上述指标缓解低温胁迫,改善轻度低温胁迫和常温处理下花生幼苗生长的干物质积累和光合生理。

单粒精播对花生干物质累积及根冠结构的影响

为明确花生单粒精播增产机理,大田条件下,以花育22为供试花生品种,以双粒穴播(DS)为对照,研究了单粒精播(SS)对花生干物质积累、叶面积系数、冠层结构和根系特征的影响。结果表明,花生生育前期单株和群体干物质重单粒精播和双粒穴播差异不显著,而生育中后期显著高于双粒穴播,结荚期叶面积系数单粒精播显著高于双粒穴播。从结荚期不同冠层结构来看,冠层上、中、下层叶面积系数单粒精播分别比双粒穴播高23.03%、9.34%、86.43%,单株和群体冠层叶片和茎干重单粒精播均显著高于双粒穴播,从冠层不同部位叶片和茎干重占总干重的比例来看,单粒精播冠层下部叶片和茎干重比例高;单株和群体总根干重、根长、根表面积和根体积高于双粒穴播,且中下层根系占比高。相关性分析结果表明,根干重与中下层的叶片干重、下层的茎干重呈显著正相关。综上所述,与双粒播相比,单粒精播花生植株冠层中下部发育健壮且根系大分布深是其增产的重要原因。单粒精播促根扩冠,是花生节本增产的一种有效途径。

花生小区播种施肥机设计与试验研究

我国花生育种小区机械化程度低,播种收获等关键环节仍以人工作业为主,劳动强度大,效率低,且易出现混种问题。为此,结合我国花生育种小区种植的农艺要求,设计了多功能花生小区播种施肥机,适宜垄作覆膜的种植模式。其在传统窝眼轮式排种器上加设净种装置,能够清除窝眼轮内剩余的种子,保证了育种小区试验的科学性;创新设计了起垄装置与覆膜装置,能够一次性完成开沟、施肥、起垄、播种及覆膜等多项作业,提高了播种机的效率。试验结果表明:机具作业后花生双粒率为99.16%,漏播率为0.6%,穴距偏差率为12.03%,重播率为0.91%,种子覆土深度合格率为90.32%,排种器清种率为100%,种子出苗率为80.90%,作业质量符合我国花生小区种植的农艺要求。该播种机的使用,提高了花生育种小区种植作业效率,为小区后续作业实施机械化提供了便利,可为育种小区机械的研发提供参考。

LEC1等转录因子基因在花生小种子突变体种子发育过程中的表达分析

花生突变体ssm1与其对照亲本鲁花11号(LH11)相比,种子皱缩变小,百仁重、单株生产力和含油量显著降低。为了探究导致该突变体种子变小且含油量降低的原因,本试验研究了种子发育关键转录因子基因LCE1等在突变体ssm1及其对照LH11合子受精及种子发育不同阶段的表达情况。结果表明,AhLEC1在花生未受精子房(DBP0)时期表达量较低,且在ssm1和对照LH11中无明显差异,在受精后的子房(DBP1)和入土10 d(DAP10)和20 d(DAP20)种子中表达量上调,并且在LH11中的表达量极显著高于突变体ssm1;转录因子基因AhFUS3、AhABI3、AhAGL15和AhWRI1在ssm1中表达均有不同程度下调。其中,与脂肪酸合成和糖酵解关系密切的AhWRI1基因在ssm1中的表达量显著下调。因此推测,ssm1中AhLEC1基因的表达量显著下调,影响AhFUS3、AhABI3和AhWRI1等基因的表达,进而导致ssm1种子胚胎发育和油脂积累的异常。

锰肥和锌肥种子包衣对花生的降镉效果

花生对土壤中的镉(Cd)具有较强的富集能力,我国花生Cd超标现象局部地区较为严重,Mn、Zn离子可通过拮抗作用降低作物对Cd的吸收,本研究探究Mn肥、Zn肥种子包衣处理对花生Cd吸收转运的影响,以期为花生产地土壤Cd污染风险管控与修复提供技术支撑。首先通过种子萌发试验筛选出3个锰(Mn)和锌(Zn)较适宜的包衣剂浓度,再进一步通过盆栽试验筛选出降镉效果最优的Mn和Zn包衣剂浓度,并探究了Mn肥和Zn肥种子包衣对Cd污染土壤上花生富集转运Cd的影响。种子萌发试验结果表明,中低浓度的Mn肥、Zn肥种子包衣处理不会影响种子发芽率且可以促进根生长,浓度过高则会明显抑制种子萌发。盆栽试验结果表明,Mn肥和Zn肥种子包衣剂中,3%锰肥包衣剂(Mn3)和2%锌肥包衣剂(Zn2)包衣处理籽粒降镉效果最显著,降镉率分别达到19.0%和24.1%,其中Zn2降镉效果更优。与对照相比,Mn3和Zn2处理根系Cd富集系数均显著降低,根向茎叶Cd转运能力明显增加,茎叶向籽粒Cd转运系数呈下降趋势,根系向籽粒Cd转运系数则无明显变化。Mn3和Zn2处理花生植株总Cd吸收量相比对照分别下降了9.18%和13.6%,花生籽粒及根系Cd含量均与根系中Mn、Zn元素含量呈显著负相关关系。综上,利用Mn、Zn种子包衣处理可通过抑制根系对Cd的吸收以及影响Cd在花生体内的转运来降低花生籽粒Cd含量。本研究提出了利用种子包衣来降低花生Cd含量的技术,为花生产地镉污染风险管控提供了新方法。

气力辅助充种式花生精量排种器设计与试验

针对花生播种向精准、高速方向发展过程中高速作业状态下花生种子充种效果差的问题,设计了一种气力辅助充种式花生精量排种器,重点设计了排种器排种盘结构和气力辅助充种结构。针对颗粒尺寸大、质量大的花生种子,通过对花生种子在排种器中堆积现象与充种时间进行分析,得出花生高速排种充种过程需增强充种性能,从而提高充种效率。通过对花生种子进行充种原理分析,阐明花生种子充种过程中种子与排种器的运动关系与受力关系,分析充种过程影响因素。通过设计带有导种槽的排种盘和带有辅助吹种型孔的辅助充种结构,分析计算排种盘吸种孔、导种槽的关键结构参数以及辅助吹种型孔参数与排列方式。以充种合格率和充种漏充率为指标,进行三因素三水平组合试验,对试验结果进行多元回归分析,以最优目标进行优化,确定排种盘最佳参数组合为排种器吸种负压5.156 kPa、花生高速播种机前进速度8.007 km/h、扰动吹种正压1.149 kPa,此时,花生充种合格率为95.84%、漏充率为4.06%,能够实现花生种子有效充种。

杀菌剂和根瘤菌剂拌种对花生根际微生物及荚果产量的影响

为筛选出能替代化学药剂的生物杀菌剂,促进花生绿色生产,本试验以湖南主栽品种湘花2008为试材,开展化学杀菌剂(甲基硫菌灵)、生物杀菌剂(哈茨木霉菌和解淀粉芽孢杆菌)单拌及与根瘤菌剂复配拌种大田试验,在花生苗期至结荚期测定根际土壤微生物数量,收获时测定荚果性状及产量。结果表明:(1)甲基硫菌灵单拌能显著促进细菌生长;甲基硫菌灵单拌、根瘤菌剂单拌及3种复配拌种处理在抑制真菌、促进根瘤菌方面表现较好;哈茨木霉单拌和解淀粉芽孢杆菌单拌对放线菌的促生效果更明显;解淀粉芽孢杆菌单拌及其复配显著抑制黄曲霉生长增殖。(2)从微生物群落结构来看,甲基硫菌灵单拌能够在全生育期提高细菌/真菌、放线菌/真菌比值,哈茨木霉单拌、解淀粉芽孢杆菌单拌二者在苗期和结荚期均能提高放线菌/真菌比值。(3)除哈茨木霉单拌及其复配外,各拌种处理均能够增加花生产量,解淀粉芽孢杆菌单拌增产最大,增幅为49.39%;根瘤菌剂单拌增产40.24%,解淀粉芽孢杆菌复配增产32.78%。结论归纳为:甲基硫菌灵单拌、哈茨木霉菌与根瘤菌剂复配、解淀粉芽孢杆菌与根瘤菌剂复配在微生物方面综合表现更好,更适宜改善花生根际土壤微生物群落;解淀粉芽孢杆菌单拌及复配、根瘤菌剂拌种在荚果产量上增幅较大。因此,推荐解淀粉芽孢杆菌单拌及复配、根瘤菌剂拌种在生产上推广使用。

柔性带式花生种子分级装置的设计与试验

针对播种前花生种子分级处理机具较少、筛孔易堵塞等问题,设计了一种柔性带式花生种子分级装置,利用种子随相邻分级带运动从不同间隙处进行分级。对主产区河南省的典型品种豫花22号花生种子物理特性进行测定,确定了分级带的布局、倾斜角度等关键参数范围。采用二次正交旋转组合试验方法设计试验,并用Design-Expert对试验结果进行数据处理,建立了分级准确率的回归数学模型并进行方差分析,得出影响分级装置准确率的主次因素依次为分级带速度、倾斜角度、分级带直径。通过响应曲面方法分析各因素交互作用对分级准确率的影响,得出关键作业参数的最优组合为分级带速度0.32 m/s、倾斜角度4.5°、分级带直径8.09 mm,此时分级准确率为97.27%。将优化参数进行进一步验证,得到分级准确率为95.84%,分级性能较好,能够满足小批量花生种子分级的需求。

微生物菌肥拌种对大豆花生增产效应的影响

为探究微生物菌肥对大豆(Glycine max)和花生(Arachis hypogaea)生长、产量及品质的影响,以大豆品种菏豆13和花生品种开农1760为材料,分别在盆栽和大田中开展微生物菌肥拌种与不拌种处理(CK),测定植株农艺性状、根系性状、叶片光合参数、土壤酶活性、产量构成和籽粒品质的变化。结果表明,与对照相比,菌肥拌种后盆栽菏豆13的株高、茎粗、叶绿素相对含量(SPAD)值、干物质积累量在开花期、结荚期显著或极显著增加,盆栽开农1760的株高、茎粗、SPAD值、干物质积累量在开花下针期、饱果期显著或极显著增加;大田内大豆、花生植株在农艺性状上的增长趋势与盆栽表现一致;对于总根长、根系总表面积、根直径、根系总体积,菏豆13较CK在开花期增幅最大,分别为27.09%、32.53%、10.84%、38.07%,开农1760的各根系性状较CK在开花下针期增幅最大,分别为63.94%、50.95%、27.14%、37.94%;菌肥拌种显著增强了植株根际土壤中脲酶、蔗糖酶、磷酸酶的活性,菏豆13较CK分别增加10.26%、45.09%、25.64%,开农1760较CK分别增加29.03%、38.30%、8.93%。同时,菌肥拌种使盆栽菏豆13的饱荚率、单株粒重、百粒重分别提高9.30个百分点、12.94%、7.75%,大田植株的饱荚数、单株粒数、单株粒重、百粒重、籽粒产量分别提高15.88%、4.67%、11.80%、7.51%、11.79%;使盆栽开农1760的单株果重、单株仁重、百仁重分别提高3.00%、9.32%、13.73%,大田植株的百仁重、饱荚率、干物质积累量、荚果产量、籽粒产量分别提高4.33%、2.33个百分点、13.99%、10.49%、9.02%。相关性分析结果表明,土壤酶活性、根系性状、光合参数之间呈现正相关的互作效应。综上,两种豆科作物经微生物菌肥拌种后,均能显著提高土壤酶活性、增强根系对土壤养分的吸收能力及叶片光合能力,并促进植株生长、提升产量和籽粒品质。本研究结果为科学施用与推广微生物菌肥提供了理论依据。

44份黑花生资源的表型遗传多样性及综合鉴评

为鉴选优异黑花生资源,以44份黑花生资源材料为研究对象,连续2年种植观测表型,研究遗传多样性和性状相关性,进行系统聚类和主成分分析。结果表明:44份黑花生资源材料的6个质量性状在品种间差异较大;19个表型性状的遗传多样性较丰富,变异系数在2.64%~97.98%之间,均值为24.28%,遗传多样性指数0.8652~2.0704之间,均值为1.7622;生育期长与第一侧枝长(r=0.82)、主茎高与第一侧枝长(r=0.87)、一次分枝数与有效结果枝数(r=0.84)、单株结果数与单株饱果数(r=0.96)、饱果重率与饱仁重率(r=0.88)、出仁率与荚果饱满度(r=0.82)之间极显著正相关,千克果数与百果重(r=–0.74)、百仁重(r=–0.62)呈极显著负相关。在欧氏距离为10.52时,可将44份黑花生资源分为6个类群。主成分分析将17个主要表型性状归为累计贡献率达89.45%的6个主成分因子,鉴选出综合得分(F值)≥0.40的资源材料6份。

低温胁迫下裂殖壶菌藻粕对花生种子萌发和幼苗生长的影响

花生是我国重要的经济和油料作物,倒春寒等低温冷害严重影响我国北方春花生产区的花生发芽和出苗率。裂殖壶菌(Schizochytrium sp.)是二十二碳六烯酸(Docosahexaenoic acid,DHA)商业化生产的代表性菌种之一,为使裂殖壶菌提取DHA后的废弃物藻粕能够被利用,本研究以青花11号花生品种为供试材料,两种不同浓度的裂殖壶菌藻粕稀释液施用为处理,分别在恒定4℃和昼夜交替(19℃/4℃)的低温环境下,测定花生种子萌发和生理相关指标。结果发现:与正常温度条件相比,低温胁迫降低了花生下胚轴长、根长、苗长和干物质积累量。在两种低温处理下,施用了藻粕液的花生种子露白率和出苗率均显著增加15%以上,干物质量、根长、苗长及下胚轴长度也均显著高于对照组;在4℃持续低温下,随着胁迫时间的延长,各处理的丙二醛(MDA)含量不断增加,藻粕液处理的花生胚芽中MDA含量显著降低,超氧化物歧化酶(SOD)、过氧化物酶(POD)活性均有上升,过氧化氢酶(CAT)活性先下降后上升,且三种酶活性都显著高于对照。本研究表明,施用裂殖壶菌藻粕对花生种子在冷害发生时起到了一定的保护作用,将为花生种子缓解倒春寒胁迫及裂殖壶菌藻粕的资源高效再利用提供解决方案,也为开发新一代的花生种子包衣剂提供了理论基础。

花生种子受低温胁迫后萌发幼苗生长及生理特性研究

花生收获期易受低温胁迫,为研究低温胁迫对不同成熟度花生种子萌发、幼苗生长和叶片生理特性的影响,以青花7号花生品种为材料,以十成熟(完熟)未受低温胁迫的种子为对照(CK),研究了九成熟2℃低温胁迫(T1)、九成熟-1℃低温胁迫(T2)、十成熟2℃低温胁迫(T3)和十成熟-1℃低温胁迫(T4)处理下种子萌发幼苗的最大光化学效率(Fv/Fm)、干物质积累和内源激素含量变化。结果表明:与CK相比,低温处理的种子萌发后幼苗Fv/Fm受到抑制,且种子成熟度越低,受低温胁迫的影响越明显;出苗后10~18 d,T1和T2处理幼苗地上部干物质重均显著低于CK,各低温处理下幼苗地下部干物质重与CK均无明显差异,但在22~26 d均显著高于CK;各处理下GA3、ZR、IAA和ABA含量随幼苗生长的变化趋势一致,但各取样时期的内源激素含量因胁迫温度和成熟度不同表现出明显差异,在出苗后10 d,T1-T4处理下萌发幼苗的(IAA+GA3+ZR)/ABA比值较CK分别降低12.82%、25.64%、25.64%和38.46%,而出苗后26 d,较CK分别提升47.62%、42.11%、60%和46.34%;温度对GA3、ZR、ABA和(IAA+GA3+ZR)/ABA比值影响极显著,对Fv/Fm值影响显著,成熟度对GA3和ZR影响极显著;(IAA+GA3+ZR)/ABA比值与幼苗干物质积累呈较强正相关,与根冠比和Fv/Fm呈现负相关。基于本研究,建议在低温冷害多发区,花生应在充分成熟后收获,以避免低温胁迫造成种子质量下降和幼苗生长受限。

Single-seed sowing increased pod yield at a reduced seeding rate by improving root physiological state of Arachis hypogaea

Double-seed sowing(two seeds per hole)is the dominant pattern of peanut sowing in China,but within-hole plant competition usually limits their growth and yield formation.Besides,the traditional double-seed sowing method does not facilitate mechanization during sowing.The objective of this study was to determine if single-seed sowing at a proper seeding rate yielded better than traditional double-seed sowing pattern and the differences of physiological metabolism of roots.A field experiment was conducted in two consecutive years to compare pod yields of single-seed sowing at 180000(S180),225000(S225),and 270000 seeds ha^-1(S270)with that of double-seed sowing at 270000 seeds ha^-1(D270)using a completely randomized block design with four replications.And the root bleeding sap rate,nutrient content,and the main hormone contents in root bleeding sap were also comparatively investigated.Although the pod yields of single-seed sowing at the three densities were higher than that of traditional double-seed sowing(D270),S225 yielded better than the other two single-seed sowing treatments(S180 and S270).The increased pod yield in single-seed sowing at 225000 seeds ha^-1 was mainly due to the higher pod dry weight per plant and harvest index.The improved pod dry weight and shoot growth had closely relationship with the enhanced root physiological traits such as the increased root bleeding sap rate,content of free amino acids,soluble sugars,K^+,Mg^2+,Zn^2+,and Ca^2+of the individual plant root.The improved activity of root reductive,nitrate reductase(NR)and ATPase and higher zeatin and zeatin riboside(Z+ZR)content of root bleeding sap were alsocrucial to the pod and shoot growth of peanut.Single-seed sowing at a moderate seeding rate(S225)is a potential practice to increase pod yield and to save seed cost.

驱导组合槽辅助附种气吸式花生高速精量排种器研究

针对现有气吸式排种器在进行花生高速播种作业时重播、漏播现象严重等问题,设计了一款驱导组合槽辅助附种气吸式高速精量排种器,在设计排种盘时将搅种凹槽、取种槽口、吸种型孔组合设计构成组合槽,实现扰种、驱种、辅助附种作用,保证高速作业时的排种性能。通过理论建模分析验证了排种盘结构设计的合理性并初步完成了关键参数的确定,借助离散元仿真软件对种群运移情况受关键参数的影响规律进行了分析,并进行了二因素五水平二次正交旋转组合试验,对结构参数进一步优化;得出搅种凹槽、取种槽口尺寸及作业速度均会对排种性能造成显著影响,并得出最优排种器参数组合:搅种凹槽深度3 mm、基圆半径70 mm;取种槽口左右端面上沿距离24.0 mm、下沿距离19.1 mm、深度10.5 mm、排种盘外周到取种槽口后端面距离24.0 mm。在该参数组合下,当风压为-6 kPa、作业速度为6~12 km/h时,粒距合格指数不小于93.33%,重播指数不大于3.52%,漏播指数不大于4.02%,破损指数不大于0.32%,具有良好的作业性能。