Increased grain yield with improved photosynthetic characters in modern maize parental lines

The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation tech-nology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are crucial for innovating new germplasm. Here, we analyzed variations in grain yield and a series of eco-physiological photosynthetic traits after anthesis in sixteen parental lines of maize (Zea mays L.) released during three different eras (1960s, 1980s, 2000s). We found that grain yield and biomass signiifcantly increased in the 2000s than those in the 1980s and 1960s. Leaf area, chlorophyl , and soluble protein content slowly decreased, and maintained a higher net photosynthesis rate (Pn) and improved stomatal conductance (Gs) after anthesis in the 2000s. In addition, the parental lines in the 2000s obtained higher actual photo-chemistry efifciency (ФPSI ) and the maximum PSII photochemistry efifciency (Fv/Fm), which largely improved light partition-ing and chlorophyl lfuorescence characteristic, including higher photochemical and photosystem II (PSII) reaction center activity, lower thermal energy dissipation in antenna proteins. Meanwhile, more lamel ae per granum within chloroplasts were observed in the parental lines of the 2000s, with a clear and complete chloroplast membrane, which wil greatly help to improve photosynthetic capacity and energy efifciency of ear leaf in maize parental lines. It is concluded that grain yield increase in modern maize parental lines is mainly attributed to the improved chloroplast structure and more light energy catched for the photochemical reaction, thus having a better stay-green characteristic and stronger photosynthetic capac-ity after anthesis. Our direct physiological evaluation of these inbred lines provides important information for the further development of promising maize cultivars.

Dissection of heterosis for yield and related traits using populations derived from introgression lines in rice

Despite the great success achieved by the exploitation of heterosis in rice,the genetic basis of heterosis is still not well understood.We adopted an advanced-backcross breeding strategy to dissect the genetic basis of heterosis for yield and eight related traits.Four testcross(TC) populations with 228 testcross F1 combinations were developed by crossing57 introgression lines with four types of widely used male sterile lines using a North Carolina II mating design.Analysis of variance indicated that the effects of testcross F1 combinations and their parents were significant or highly significant for most of the traits in both years,and all interaction effects with year were significant for most of the traits.Positive midparent heterosis(HMP) was observed for most traits in the four TC populations in the two years.The relative HMPlevels for most traits varied from highly negative to highly positive.Sixty-two dominant-effect QTL were identified for HMPof the nine traits in the four TC populations in the two years.Of these,22 QTL were also identified for the performance of testcross F1.Most dominant-effect QTL could individually explain more than 10% of the phenotypic variation.Four QTL clusters were observed including the region surrounding the RM9–RM297 region on chromosome 1,the RM110–RM279–RM8–RM5699–RM452 region on chromosome 2,the RM5463 locus on chromosome 6 and the RM1146–RM147 region on chromosome 10.The identified QTL for heterosis provide valuable information for dissecting the genetic basis of heterosis.

Dissection of QTLs for Yield Traits Using Near Isogenic Lines Derived from Residual Heterozygous Lines in Rice

Three residual heterozygous lines (RHLs) carrying heterozygous segments in the intervals RM587–RM225, RM204–RM6119 and RM6119–RM402 on the short arm of rice chromosome 6, respectively, were selected from a rice population derived from an RHL for the interval RM587–RM402. Ten maternal homozygotes, 10 paternal homozygotes and 20 heterozygotes were selected from each of the F2 populations derived from the three RHLs. The three sets of near isogenic lines (NILs) were grown to detect the grain yield per plant, number of panicles per plant, number of filled grains per panicle and 1000-grain weight. With analysis on the phenotypic differences among the three genotype groups in each NIL set and those among overlapping chromosome segment substitution lines, three QTLs for number of filled grains per panicle and two QTLs for grain yield per plant were resolved. They were located in the intervals ranging from 0.66 Mb to 2.49 Mb. The additive effect was higher than the dominance effect at each locus. The allele for increasing the trait value was derived from the paternal parent at qNFGP6-1, and from the maternal alleles at other QTLs. Based on the present study, an approach for constructing new genetic resource to facilitate fine mapping of QTLs in rice was proposed.

Yield Traits and Associated Marker Segregation in Elite Introgression Lines Derived from O. sativa × O. nivara

Introgression lines(ILs)derived from interspecific crosses are a source of new genetic variability.A total of 55 ILs derived from two crosses Swarna×O.nivara IRGC81848(population A)and Swarna×O.nivara IRGC81832(population B)were characterized for yield and yield-related traits/QTLs.Segregation of 103 simple sequence repeat(SSR)markers associated with yield-related QTLs was studied.Population A showed an average of 12.6%homozygous O.nivara alleles and population B showed 10.6%.Interestingly,three SSR markers,RM223,RM128 and RM517,showed conspicuous pattern of segregation.The distribution of parental alleles at three loci RM223,RM128 and RM517 linked to yield-related traits was unique.These markers flanked to several yield-related QTLs.RM223,flanking to qyld8.3,was heterozygous in almost all the 55 ILs except in IL10-3S and IL131S.RM128 on chromosome 1 and RM517 on chromosome 3 were mutually exclusive in 46 out of 55 ILs.These 46 ILs showed either of the marker allele RM128 or RM517 from O.nivara but not both.IL166S had both RM128and RM517 from O.nivara and the other ILs showed homozygous Swarna allele at RM517 except IL65S.Population structure assigned the 55 ILs to three sub-populations based on their genomic diversity.IL65S,IL166S,IL248S,IL7K and IL250K showed high yields in multi-location trials,and IL248S was released for cultivation as DRRDhan 40.

内层钢板外层高强度混凝土复合井壁受力特性与支护结构参数优化分析

针对内层钢板外层高强度混凝土复合井壁的厚度设计,以受均匀围压的内层钢板外层高强度混凝土复合井壁得出的弹性解析解为基础,对内层钢板采用Mises屈服准则,外层高强度混凝土采用统一强度理论,研究复合井壁的初始屈服临界状态.以内层钢板和外层高强度混凝土均未屈服为条件,提出复合井壁的设计流程.结果表明,当内半径、围压以及材料给定时,存在外半径和分层半径的最佳取值范围,在此范围内选择外半径和对应的分层半径,内层钢板和外层高强度混凝土均不会达到屈服.与模型试验进行对比,发现试验中内半径、外半径、分层半径和材料给定的复合井壁,当围压等于设计围压时,外半径和分层半径处于最佳取值范围;当围压继续增大时,外层高强度混凝土先于内层钢板屈服.弹性解与屈服准则相结合,得到复合井壁设计流程为:通过规范及工程地质条件确定井壁内半径和围压值,选定复合井壁的材料,采用屈服准则求得外半径和分层半径的最佳取值范围.

四川盆地设施避雨栽培对线椒生长、激素和产量的影响

探讨四川盆地设施避雨栽培对线椒生长、激素和产量的影响,明确影响机制。以线椒‘川椒20’为试验材料,设置设施避雨处理和露地对照,测定2个处理中线椒株高、顶端组织激素含量,并对其进行转录组测序和有关基因的qRT-PCR验证。结果表明,设施避雨栽培后线椒株高前期无显著差异,中后期避雨栽培株高分别是露地栽培的1.13、1.5倍;设施避雨栽培单株产量为露地栽培单株产量的74.9%;避雨栽培后赤霉素含量是露地栽培的1.29倍,茉莉酸含量是露地栽培的63.3%。GO分析发现,2个处理生物功能主要在胁迫反应和防御反应方面显著富集,分子功能方面,在腺嘌呤核糖核苷酸结合、腺苷酸结合、二磷酸腺苷结合显著富集。KEGG通路分析发现,相对于避雨栽培,露地栽培线椒在二萜生物合成代谢途径中,CaGA2ox1.1(Gibberellin 2-beta-dioxygenase 1,T459_20483)、CaGA2ox1.2(Gibberellin 2-beta-dioxygenase 1,T459_24753)、CaGA2ox8(Gibberellin 2-beta-dioxygenase 8,T459_05864)、CaGRP3(Gibberellin-regulated protein 3,T459_06266)4个与赤霉素降解有关的基因下调表达。四川盆地设施避雨栽培后,线椒顶端组织赤霉素降解基因表达量降低,赤霉素含量增高,造成线椒徒长,最终导致设施避雨栽培后的线椒产量低于露地栽培。

钢坯定重动态智能调控技术探讨

近年来,随着棒材生产多线切分常态化,高速棒材生产技术及钢坯免加热直接轧制技术日益成熟,并得到广泛应用。在棒材生产过程中,许多企业实现了钢坯快速输送并直接轧制,生产效率大大提高。但是,轧钢生产线要求连铸工序对钢坯进行定重控制,采用跨单位电话通知方式进行人工调整,响应速度慢、稳定性差,难以满足快节奏的生产模式,导致轧后通尺量大,严重制约成材率指标的提高。因此,从连铸到轧钢工序系统考虑,通过建立数学模型,运用在线检测、信息计算技术,实现生产过程的动态调整,达到无人干预并自动控制的目的,为生产线实现高效智能制造提供切实可行的技术控制方法。

施氮量与行距对赖草种子产量及质量的影响

为探究氮肥施用量与行距对赖草(Leymus secalinus)种子产量及质量的影响,本研究采用裂区试验设计,主区为氮肥添加量(N00 kg·hm^(-2),N160 kg·hm^(-2),N2120 kg·hm^(-2),N3180 kg·hm^(-2)),副区为行距(R130 cm,R240 cm,R350 cm,R460 cm),利用灰色关联度、逐步回归分析等方法对种子产量及质量综合分析,明确影响种子产量的关键因素,筛选赖草种子生产最优种植配置组合。结果表明:影响赖草种子产量的主要因素是生殖枝数、千粒重、种子数/小穗、小穗数/生殖枝,对产量贡献最大的因素是种子数/小穗。经灰色关联分析可知,120~180 kg·hm^(-2)施氮量和60 cm种植行距时获得最优的种子产量与种子质量,而120 kg·hm^(-2)施氮量处理下的实际种子产量、潜在种子产量与180 kg·hm^(-2)施氮量处理均无显著差异,因此从经济效益与生态效益考虑,赖草种子生产可采用120 kg·hm^(-2)施氮量、60 cm行距,能获得最优的种子产量与质量。

基于无人机高光谱遥感与机器学习的小麦品系产量估测研究

为快速、准确地估测小麦产量,有效提高育种工作效率,本文以小麦品系为研究对象,收集小麦灌浆期无人机高光谱数据和产量数据。首先基于递归特征消除法筛选出特征波长作为模型输入变量,然后利用岭回归(Ridge regression,RR)、偏最小二乘回归(Partial least squares regression,PLS)、多元线性回归(Multiple linear regression,MLR)3种线性算法和随机森林(Random forest,RF)、梯度提升回归(Gradient boosting regression,GBR)、极限梯度提升(eXtreme gradient boosting,XGB)、高斯过程回归(Gaussian process regression,GPR)、支持向量回归(Support vector regression,SVR)、K最邻近算法(K-nearest neighbor,KNN)6种非线性算法构建单一算法产量估测模型并进行精度比较,最后基于Stacking算法构建多模型集成组合,筛选最佳集成模型。结果表明,基于不同算法的产量估测模型精度差异显著,非线性模型优于线性模型,基于GBR的产量估测模型在单一模型中表现最优,训练集R^(2)为0.72,RMSE为534.49 kg/hm^(2),NRMSE为11.10%,测试集R^(2)为0.60,RMSE为628.73 kg/hm^(2),NRMSE为13.88%。基于Stacking算法构建的集成模型性能与初级模型和次级模型的选择密切相关,以KNN、RR、SVR为初级模型组合,GBR为次级模型的集成模型有效提高了估测精度,相比单一模型GBR,训练集R^(2)提高1.39%,测试集R^(2)提高3.33%。本研究可为基于高光谱技术的小麦品系产量估测提供应用参考。

Study on the Relationship of Seedling Density and Line Spacing to Leaf-stem Ratio, DW/FW Ratio and Grass Yield of Forage Sweet Sorghum

[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] Effects of such two influencing factors as line spacing and seedling density on the leaf-stem ratio, DW/FW ratio and grass yield of forage sweet sorghum were analyzed by using split-plot experiment design experiment method and LSD method of IBM. SPSS. Statis- tics. v22 stati, stics software. [ Results ~ Seedling density and line spacing had no obvious effect on the leaf-stem ratio and DW/FW ratio of forage sweet sorghum but had obvious influences on the grass yield. Moreover, the optimal combination of seedling density and line spacing for high yield of forage sweet sorghum was A2 B4, that is, seedling density was 225 000 plants/hm2, and line spacing was 40 cm. [ Conclusions] The results provided a theoretical basis and technical support for high-yield cultivation techniques of forage sweet sorghum.

基于主成分和聚类分析7个深绿线椒品种的商品品质和产量评价

【目的】探明深绿线椒品种的商品品质和产量差异,为贵州辣椒产业品种结构调整和优势区域布局提供科学依据。【方法】以7个深绿线椒品种(长辣七号、湘辣17号、卓椒七号、卓椒八号、香辣八号、红冠303、泰丰五号)为研究对象,采用SPSS 26.0进行变异系数分析和主成分分析,Origin 2022进行相关性和聚类分析,对其商品品质与产量进行综合评价。【结果】7个深绿线椒品种的商品品质及产量性状变异系数为6.91%~28.17%,其中,以果形指数变异系数最小,单果鲜重的变异系数最大;单果鲜重与果纵径、鲜椒产量与干物质含量分别呈极显著相关性,果纵径与果横径、单果鲜重与果横径、干椒产量与单株挂果数、单株挂果数与果纵径、单株挂果数与单果鲜重、单果鲜重与干物质含量分别呈显著相关性。基于深绿线椒品种的9个性状,通过主成分分析建立综合表现评价模型,得出品种卓椒七号的综合表现最佳,其产量最高,达2410 kg/667m^(2)。聚类分析将7个线椒品种分为适合鲜加工(长辣七号、红冠303、香辣八号和湘辣17号)、既适合鲜加工又适合干加工(泰丰五号和卓椒八号)及适合绿熟期采收上市(卓椒七号)3类。【结论】7个深绿线椒品种的多样性丰富,单果鲜重、果横径、果纵径、单株挂果数是构成鲜椒产量的主要因素,单株挂果数是构成干椒产量的主要因素;卓椒七号鲜椒产量最高,适合在绿熟期采收上市;卓椒八号果形和果肉厚适中,鲜椒和干椒产量中上,是理想的加工型辣椒品种。

面向育种应用的高州野生稻片段导入系构建与产量性状QTL分析

野生稻是水稻育种的宝贵基因库,但基因组杂合性高,与栽培稻差异大,为育种上直接利用野生稻带来了困难。构建野生稻片段导入系为挖掘和利用野生稻基因资源提供了有效的技术手段。本研究以广东高州野生稻为供体,粳稻品种中花11为受体,通过多代杂交和自交,以育种目标性状为筛选标准,甄选出100个片段导入系。对这100个导入系的产量相关性状(单株有效穗数、总实粒数、千粒重、每穗实粒数和单株产量)进行考察,发现它们至少有1个性状要优于对照品种中花11,显示出在产量改良上的应用潜力。导入系全基因组覆盖度46.9%,共识别出20个产量相关QTL。这些片段导入系作为高州野生稻新型种质资源,为利用野生稻助力水稻种质创新提供了资源储备。

春小麦重组自交系品质性状与产量、生理性状相关性分析

以‘宁春4号’与‘宁春27号’为亲本杂交构建重组自交系的128份家系为材料,测定该群体的产量、叶面积指数、碳同位素分辨率、面筋含量等20个性状,分析各性状间的相关性。结果表明,该群体有丰富的变异类型,各性状离散程度较大,存在较大程度的超亲遗传。相关性分析表明生理性状与品质性状间有较强相关性,冠层温度、碳同位素分辨率对品质与产量性状影响较大;产量性状与品质性状大都呈正相关。以差异极显著的20个性状进行主成分分析,选取特征向量累积贡献率达87%的性状,分别是沉降值、稳定时间、湿面筋含量、硬度指数、粗蛋白含量、不实小穗数、穗粒数、吸水率、株高、结实小穗数、冠层温度、千粒质量与碳同位素分辨率;基于各性状聚类共分为9个类群,第九类群材料高产优质且农艺水分利用效率较高,为今后育种工作提供重要材料。

On the excavation-induced stress drop in damaged coal considering a coupled yield and failure criterion

Investigating the stress drop of abutment pressure is the key to a deep quantitative analysis of the discontinuous stress redistribution under mining.In the present study,uniaxial and triaxial compression tests are carried out separately to determine the bulk and shear moduli,the cohesion,and the internal friction angle of the coal samples.By extending the meaning of Mohr’s circle referring to yield stress instead of the maximum principal stress,a yield line is introduced to illustrate the stress drop of Mohr’s circle referring to yield stress instead of the maximum principal stress at the elastoplastic boundary.Furthermore,a theoretical solution of the stress drop as a function of the damage is proposed to investigate how the abutment pressure differs considering the yield line and failure line.In addition,applying the stress drop at the yield line in non-pillar mining,top coal mining,and protective coal mining shows that the damage has a nonlinearly positive influence on the stress drop.The results shows that the bulk modulus and internal friction angle have a more sensitive influence on the stress drop than do the shear modulus and cohesion.Finally,the stress drop is divided into a discontinuous stress drop at the yield line and a structural stress drop at the failure line.The stress drop is effective in describing the discontinuous stress redistribution and shows a clear difference in the movement direction of Mohr’s circle considering the unloading pressure.

密度和行距配置对榆林市春玉米农艺性状和产量的影响

为研究不同密度和行距配置对榆林地区春玉米农艺性状和产量的影响,以陕单650、大丰30为供试品种,设置2行1带40 cm+80 cm(A)、3行1带40 cm+40 cm+120 cm(B)、3行1带60 cm+60 cm+120 cm(C)、4行1带40 cm+40 cm+40 cm+120 cm(D)、4行1带60 cm+60 cm+60 cm+120 cm(E)宽窄行和对照60 cm等行距(F,CK)6个行距配置模式,设置67500、90000株/hm^(2)2个种植密度,采用3因素裂区试验设计,种植模式为主区,品种和密度为副区,探究不同行距配置下玉米农艺性状及产量的差异。结果表明:同一品种,玉米株高和穗位高均随着密度的增大而增加,茎粗则随着密度的增加而降低;不同行距配置中3行1带(60 cm+60 cm+120 cm)处理的株高、穗位高明显高于其他行距配置水平,茎粗则相反。玉米籽粒产量随着密度的增加均有所增加。同一品种相同种植模式下,90000株/hm^(2)明显比67500株/hm^(2)产量要高。穗粗、穗长、穗行数、行粒数、百粒重均随着种植密度的增加而降低,秃尖长则随着密度的增加而增加。陕单650的最高产量种植方式为:90000株/hm^(2)密度下3行一带(40 cm+40 cm+120 cm)行距配置模式,产量为18504.15 kg/hm^(2);其次为90000株/hm^(2)密度下的3行1带(60 cm+60 cm+120 cm)行距配置水平,产量为17768.55 kg/hm^(2);大丰30的最高产量种植方式为90000株/hm^(2)密度下的3行1带(60 cm+60 cm+120 cm)行距配置水平,产量为19421.40 kg/hm^(2)。

水稻小粒不育系新组合卓两优1126的高产特征

[目的]挖掘杂交水稻产量潜力,培育超高产品种,既是一道科学难题,也是“藏粮于技”安全战略。本研究旨在解析小粒不育系卓201S配组的杂交稻卓两优1126高产形成规律,为优质高效超级杂交稻培育提供理论支撑。[方法]2022年选用小粒不育系新组合卓两优1126和对照品种超级稻两优培九、Y两优900和湘两优900为试验材料,在湖南省隆回县统一高产栽培,系统比较卓两优1126与其他3个超级杂交稻产量及其产量构成、干物质积累、根系发育和抗倒性,探究小粒不育系新组合卓两优1126高产特征。[结果]卓两优1126产量极显著高于对照,较超级杂交稻第1期代表品种两优培九增产35.07%,较超级杂交稻第4期代表品种Y两优900增产17.84%,较超级杂交稻新代表品种湘两优900增产14.52%。卓两优1126产量的提高主要原因是在保持稳定千粒重和结实率基础上,通过平衡有效穗数与每穗粒数使群体总颖花数显著提升。与对照相比,卓两优1126单茎地上部干质量、根干质量和根冠比均极显著高于对照,表明卓两优1126根系具有显著的生长优势,能够很好地协调植株地下和地上部分的生长,有助于超高产的形成。卓两优1126株高适中,基部3节间总长和穗下节间长度都极显著高于对照,但基部第2节间的弯曲力矩和抗折力与湘两优900的差异未达到显著水平,卓两优1126在增加株高的同时保持了较强的抗倒性。卓两优1126耐低氮,稻米品质综合评级为部标优质2级,极端高温下较对照Y两优1928增产5.53%。[结论]卓两优1126在保持稳定的千粒重和结实率基础上,通过平衡有效穗数与每穗粒数使群体总颖花数显著提升,从而实现超高产。卓两优1126亲本间粒型存在显著差异,可以实现父母本混播混收的全程机械化制种,降低种子生产成本。另外,小粒型不育系千粒重仅为常规不育系的1/2,在制种产量保持不变的前提下,单位制种面积的杂交稻种子粒数比普通不育系多1倍,大幅降低杂交稻的用种成本。因此,以卓两优1126为代表的“小粒种高产稻”模式,能为解决杂交水稻当前困境提供新思路,是新的发展方向。

The Principal Component Analysis on Yielding and Agronomic Traits of Hybrid Rice of Liangyou 2111

In order to define the relationship between yield and important agronomic traits of two lines hybrid Uangyou 2111, the principal component analysis method was used to analyze the expadmental data of six test points in Yunnan Province. The results showed that the main factors influencing the production of Liangyou 2111 were grain number, grains seed number, panicle length, growth padod and panicle rate; then were 1 O00-grain weight, seed setting rate, effective panicle and highest stem tillers number; again was plant height. Therefore, when hybrid rice of Uangyou 2111 will be planted widely in yunnan province, we should focus on en- sudng the panicle traits, especially increase grain number and grain seed number, and coordinately develop other traits to achieve high yield.

深埋圆形隧道衬砌-锚杆支护结构弹塑性解答

文章采用等效材料法,基于Drucker-Prager屈服准则推导了具有衬砌-锚杆支护深埋隧道在不同施工阶段下的弹塑性解答,并进行FLAC3D数值模拟验证。结果表明:塑性区位于衬砌内部,锚杆的锚固作用对其塑性区扩展响应不明显,塑性区扩展到锚固区,软岩中锚杆锚固作用对抑制塑性扩展的响应较好;塑性区扩展到锚固区时,塑性区半径与锚杆的弹性模量呈负相关趋势,塑性区半径与锚杆的支护角度呈正相关趋势,软岩中锚杆锚固作用对抑制塑性区扩展的效果更为明显。

基于屈服线理论的混凝土护栏和桥面板悬臂设计研究

为提高桥梁混凝土护栏和桥面板悬臂抗撞性能,文章论述了混凝土护栏的车辆横向撞击力的三要素,建议了其最小作用高度;依据屈服线理论和虚功原理推导了混凝土护栏对横向荷载的抗力标准值和屈服线发生的临界长度。结果表明:通过实例验证了混凝土护栏和《公路桥涵通用图》桥面板悬臂的抗撞性能,混凝土护栏的极限承载力满足车辆横向碰撞的要求,而空心板桥面板悬臂的抗撞性能不足,并提出了设计建议,以为桥梁设计提供借鉴和参考。

青贮玉米自交系主要农艺性状与产量性状分析

为了探讨青贮玉米自交系主要农艺性状对产量的影响,筛选出综合性状优良的自交系用于青贮玉米育种。本研究对17个青贮玉米自交系材料的植株性状、果穗性状、产量性状进行方差分析、变异分析、相关性分析。结果表明,N00、温611自交系的株高、穗位高、全株干重、全株鲜重、籽粒产量均显著或极显著高于大部分自交系,可作为今后通用型粮饲青贮玉米育种的骨干亲本。各性状变异系数依次为:秃尖长>籽粒产量>雄穗分枝>全株鲜重>全株干重>百粒重>穗位高>株高>穗行数>茎粗>出籽率。相关系数表明,调查的8个主要农艺性状中对产量影响较大的是株高、穗位高、百粒重、出籽率、茎粗,在自交系的培育中应着重挑选穗位、株高、出籽率、粒重和茎粗等性状,同时还需把雄穗分枝、秃尖长等其他性状作为综合考虑的因素。