A Yield Mapping Procedure Based on Robust Fitting Paraboloid Cones on Moving Elliptical Neighborhoods and the Determination of Their Size Using a Robust Variogram

The yield map is generated by fitting the yield surface shape of yield monitor data mainly using paraboloid cones on floating neighborhoods. Each yield map value is determined by the fit of such a cone on an elliptical neighborhood that is wider across the harvest tracks than it is along them. The coefficients of regression for modeling the paraboloid cones and the scale parameter are estimated using robust weighted M-estimators where the weights decrease quadratically from 1 in the middle to zero at the border of the selected neighborhood. The robust way of estimating the model parameters supersedes a procedure for detecting outliers. For a given neighborhood shape, this yield mapping method is implemented by the Fortran program paraboloidmapping.exe, which can be downloaded from the web. The size of the selected neighborhood is considered appropriate if the variance of the yield map values equals the variance of the true yields, which is the difference between the variance of the raw yield data and the error variance of the yield monitor. It is estimated using a robust variogram on data that have not had the trend removed.

pH值对磷酸铵镁(MAP)晶体生成的影响研究

在MAP生成过程中,溶液的pH的影响和变化都十分明显,重点研究了pH值对MAP生成过程、产量及晶型的影响。溶液的pH值在8~11范围内,随着MAP晶体的形成,溶液的pH值急剧下降,加药8 min后迅速降低至7左右。但是当溶液的pH值增加到12后,其变化变缓,但沉淀物中杂质成分明显增加,基本不再生成MAP晶体。MAP产量影响实验表明:pH值10为最佳MAP生成条件,此时晶体产量高达2.52 g,且沉淀物中杂质成分很少,主要为磷酸铵镁晶体。沉淀物的SEM和XRD谱图分析显示:pH值不同,沉淀物的成分是不一样的。pH值为8~10条件下,主要为磷酸铵镁。pH值为11~12时,沉淀物成分较为复杂,主要为磷酸镁、氢氧化镁、磷酸铵镁的混合物。研究结果表明:在磷酸铵镁晶体的形成过程中,溶液pH值的影响十分显著。

Major Gene Identification and Quantitative Trait Locus Mapping for YieldRelated Traits in Upland Cotton(Gossypium hirsutum L.)

Segregation analysis of the mixed genetic model of major gene plus polygene was used to identify the major genes for cotton yield-related traits using six generations P1, P2, F1, B1, B2, and F2 generated from the cross of Baimian 1 x TM-1. In addition to boll size and seed index, the major genes for the other five traits were detected： one each for seed yield, lint percentage, boll number, lint index; and two for lint yield. Quantitative trait locus/loci （QTL） mapping was performed in the F2 and F2：3 populations of above cross through molecular marker technology, and a total of 50 QTL （26 suggestive and 24 significant） for yield-related traits were detected. Four common QTL were discovered： qLP-3b（F2）/qLP-3（F2：3） and qLP-19b （F2）/qLP-19（F2：3） for lint percentage, qBN-17（F2）/qBN-17（F2：3） for boll number, and qBS-26b（F2）/qBS-26（F2：3） for boll size. Especially, qLP- 3b（Fz）/qLP-3（F2：3）, not only had LOD scores 〉3 but also exceeded the permutation threshold （5.13 and 5.29, respectively）, correspondingly explaining 23.47 and 29.55% of phenotypic variation. This QTL should be considered preferentially in marker assisted selection （MAS）. Segregation analysis and QTL mapping could mutually complement and verify, which provides a theoretical basis for genetic improvement of cotton yield-related traits by using major genes （QTL）.

Association mapping of quantitative trait loci for yield-related agronomic traits in rice(Oryza sativa L.)

High yield in rice mainly depends on large grain weight, ideal plant architecture and proper flowering time adapting to various geographic regions. To help achieve higher yield, phenotype variations of heading date（HD）, plant architecture and grain shape in a panel of 416 rice accessions were investigated in this study. A total of 143 markers including 100 simple sequence repeat（SSR） markers and 43 gene-tagged markers were employed in association mapping to detect quantitative trait loci（QTL） responsible for these variations. Among the 7 subpopulations, POP5 in japonica group showed the largest values of HD and grain width（GW）, but the smallest values of grain length（GL） and grain length to width ratio（GLW）. Among the six indica groups, POP7 had the largest values of HD, GL, GLW, and 1 000-grain weight（TGW）. A total of 27 QTLs were detected underlying these phenotypic variations in single year, while 12 of them could be detected in 2006 and 2007. GS3 marker was closely associated with GL, GW and GLW, and widely distributed in different groups. The starch synthesis related gene markers, SSI, SSIIa, SBE1, AGPL4, and ISA1, were linked to plant height（PH）, panicle length（PL）, flag leaf length（FLL）, GW, and GLW. The SSR markers, RM267, RM340 and RM346, were linked to at least two traits. Therefore, these new markers will probably be used to improve rice grain yield or plant architecture when performing marker-assisted selection of proper alleles.

QTL mapping for fiber quality and yieldrelated traits across multiple generations in segregating population of CCRI 70

Background:Cotton is a significant economic crop that plays an indispensable role in many domains.Gossypium hirsutum L.is the most important fiber crop worldwide and contributes to more than 95%of global cotto n production.Identifying stable quantitative trait locus(QTLs)controlling fiber quality and yield related traits are necessary prerequisites for marker-assisted selection(MAS).Results:A genetic linkage map was constructed with 312 simple sequence repeat(SSR)loci and 35 linkage groups using JoinMap 4.0;the map spanned 1 929.9 cM,with an average interval between two markers of 6.19 cM,and covered approximately 43.37%of the cotton genome.A total of 74 QTLs controlling fiber quality and 41 QTLs controlling yield-related traits were identified in 4 segregating generations.These QTLs were distributed across 20 chromosomes and collectively explained 1.01%?27.80%of the observed phenotypic variations.In particular,35 stable QTLs could be identified in multiple generations,25 common QTLs were con sistent with those in previous studies,and 15 QTL clusters were found in 11 chromosome segments.Conclusion:These studies provide a theoretical basis for improving cotton yield and fiber quality for molecular marker-assisted selection.

饮用水中微生物可利用磷(MAP)的测定方法研究

研究细化了微生物可利用磷(MAP)的测定方法,采用配水试验得出不同磷浓度与对应浓度下生长的P17菌最大菌落数N_(max)有较好的线性关系。试验测定的MAP产率系数为1.10×10~9CFU/μg PO_4^(3-)-P,MAP测定适用范围为0.5～10μg/L(以PO_4^(3-)-P计)。经过分析提出MAP测定可以用第3,4天的P17菌落数最大值代替最大菌落数N_(max),减少了MAP测定工作量。对某市给水处理工艺和配水管网中MAP占总磷的百分比分析表明,微生物可利用磷与总磷并没有固定的比例关系。

Mapping spatial variation in acorn production from airborne hyperspectral imagery

Masting is a well-marked variation in yields of oak forests. In Japan, this phenomenon is also related to wildlife management and oak regeneration practices. This study demonstrates the capability of integrating remote sensing techniques into map- ping spatial variation of acorn production. The hyperspectral images in 72 wavelengths （407-898 nm） were acquired over the study area ten times over a period of three years （2003-2005） during the early growing season of Quercus serrata using the Airborne Im- aging Spectrometer Application （AISA） Eagle System. With the canopy spectral reflectance values of 22 sample trees extracted from the images, yield estimation models were developed via multiple linear regression （MLR） analyses. Using the object-oriented classi- fication approach in eCognition, canopies representative of individual oak trees （Q. serrata） were identified from the corresponding hyperspectral imagery and combined with the fitted estimation models developed, acorn yield over the entire forest were estimated and visualized into maps. Three estimation models, obtained for June 27 in 2003, July 13 in 2004 and June 21 in 2005, showed good performance in acorn yield estimation both for the training and validation datasets, all with R2 〉 0.4, p 〈 0.05 and RRMSE 〈 1 （the relative root mean square of error）. The present study shows the potential of airborne hyperspectral imagery not only in estimating acorn yields during early growing seasons, but also in identifying Q. serrata from other image objects, based on which of the spatial distribution patterns of acorn production over large areas could be mapped. The yield map can provide within-stand abundance and valuable information for the size and spatial synchrony of acorn production.

QTL mapping in A-genome diploid Asiatic cotton and their congruence analysis with AD-genome tetraploid cotton in genus Gossypium

Asiatic cotton （Gossypium arboreum L.） is an Old World cultivated cotton species. The sinense race was planted extensively in China. Due to the advances in spinning technology during the last century, the species was replaced by the New World allotetraploid cotton G. hirsutum L. Gossypium arboreum is still grown in India and Pakistan and also used as an elite in current cotton breeding programs. In addition, G. arboreum serves as a model for genomic research in Gossypium. In the present study, we generated an A-genome diploid cotton intraspecific genetic map including 264 SSR loci with three morphological markers mapped to 13 linkage groups. The map spans 2,508.71 cM with an average distance of 9.4 cM between adjacent loci. A population containing 176 F2：3 families was used to perform quantitative trait loci （QTL） mapping for 17 phenotypes using Multiple QTL Model （MQM） of MapQTL ver 5.0. Overall, 108 QTLs were detected on 13 chromosomes. Thirty-one QTLs for yield and its components were detected in the F2 population. Forty-one QTLs for yield and its components were detected in the F2：3 families with a total of 43 QTLs for fiber qualities. Two QTLs for seed cotton weight/plant and lint index and three QTLs for seed index were consistently detected both in F2 and F2：3. Most QTLs for fiber qualities and yields were located at the same interval or neighboring intervals. These results indicated that the negative correlation between fiber qualities and yield traits may result from either pleiotropic effect of one gene or linkage effects of multiple closely linked genes.

Identification and QTL mapping of Z550, a rice backcrossed inbred line with increased grains per panicle

An elite backcrossed inbred line Z550 with increased grains per panicle was identified from advanced backcrosses between Nipponbare and Xihui 18 by simple sequence repeat(SSR) marker-assisted selection(MAS). Z550 carries 13 substitution segments distributed on chromosomes 1, 6, 7, 8, 9, 10, and 12, with an average substitution length of 1.68 Mb. Compared with the Nipponbare parental line, plant height, panicle length, spikelets per panicle, grains per panicle, and grain weight for Z550 were significantly increased. While the grain width of Z550 was significantly narrower, and the seed setting ratio(81.43%) was significantly lower than that of Nipponbare, it is still sufficient for breeding purposes. Quantitative trait loci(QTLs) mapping for important agronomic traits was conducted with the F_2 population derived from Nipponbare crossed with Z550 using the restricted maximum likelihood(REML) method. A total of 16, including 12 previously unreported QTLs were detected, with contribution rates ranging from 1.46 to 10.49%. Grains per panicle was controlled by 8 QTLs, 5 of which increased number of grains whereas 3 decreased it. qGPP-1, with the largest contribution(10.49%), was estimated to increase grains per panicle by 30.67, while q GPP-9, with the minimum contribution rate(2.47%), had an effect of increasing grains per panicle by 15.79. These results will be useful for further development of single segment substitution lines with major QTLs, and for research of their molecular functions via QTL cloning.

Gene mapping and candidate gene analysis of aberrant-floral spikelet 1(afs1) in rice(Oryza sativa L.)

The spikelet is a unique inflorescence structure in grasses. However, the molecular mechanism that regulates its development remains unclear, and we therefore characterize a spikelet mutant of rice(Oryza sativa L.), aberrant-floral spikelet 1(afs1), which was derived from treatment of Xinong 1 B with ethyl methanesulfonate. In the afs1 mutant, the spikelet developed an additional lemma-like organ alongside the other normally developed floral organs, and the paleae were degenerated to differing degrees with or without normally developed inner floral organs. Genetic analysis revealed that the afs1 phenotype was controlled by a single recessive gene. The AFS1 gene was mapped between the insertion/deletion(In Del) marker Indel19 and the simple sequence repeat marker RM16893, with a physical distance of 128.5 kb on chromosome 4. Using sequence analysis, we identified the deletion of a 5-bp fragment and a transversion from G to A within LOC_Os04 g32510/LAX2, which caused early termination of translation in the afs1 mutant. These findings suggest that AFS1 may be a new allele of LAX2, and is involved in the development of floral organs by regulating the expression of genes related to their development. The above results provide a new view on the function of LAX2, which may also regulate the development of spikelets.

硅片Map图信息的提取和利用

分析了硅片Ｍａｐ图所提供的生产成品率和各类不合格芯片的位置分布信息，讨论了利用硅片之间Ｏｖｅｒｌａｐ法（重叠法）和硅片上Ｗｉｎｄｏｗ法（窗口法）对Ｍａｐ图进行的统计。着重讨论了：按硅片中不合格芯片密度的显著差异划分边缘区及中心区；不合格芯片局部聚集现象的定量表示；随机性强的不合格芯片的统计分布；有关信息由相应Ｃ语言软件自动提取，与Ｍａｐ图计算机测试进行联用，可用于生产监控、影响成品率因素分析和工艺缺陷的深入研究。

Genotype × Environment Interactions for Agronomic Traits of Rice Revealed by Association Mapping

Agronomic traits are important determinants to rice yield, which are controlled by complex genetic factors as well as genotype by environment （G × E） interaction effects. The G × E effects for agronomic traits of rice have been dissected with various approaches, but not with the current available approach, the association studies. In this study, a total of 32 655 single nucleotide polymorphisms were used to carry out associations with 14 agronomic traits among 20 rice accessions in two environments. The G × E interaction effects for all the agronomic traits were at highly significant levels （P〈0.01）, accounting for 3.4%-22.3% of the total sum of squares except for the length of brown rice. Twenty three putative quantitative trait loci （QTLs）, including five previously known and several new promising associations, were identified for 10 of 14 traits. Analysis of the relationships between the traits for which QTLs and the genotype effects could be identified suggested that the higher the genotypic effect, the higher the possibility to identify QTLs for the given trait. The new QTLs detected in this study will facilitate dissection of the complex agronomic traits and may give insight into the G × E effects with association mapping.

Identification of QTL for kernel number-related traits in a rice chromosome segment substitution line and fine mapping of qSP1

A chromosome segment substitution line (CSSL) is a powerful tool for combining quantitative trait locus (QTL) mapping with the pyramiding of desirable alleles. The rice CSSL Z1364 with increased kernel number was identified in a BC3F8 population derived from a cross of Nipponbare as the recipient with Xihui 18 as the donor parent. Z1364 carried three substitution segments distributed on chromosomes 1, 6, and 8. The mean substitution length was 1.19 Mb. Of 17 QTL identified on the substitution segments, qSP1 for spikelets per panicle, qSSD1 for seed-set density, and qNSB1 for number of secondary branches explained respectively 57.34%, 87.7%, and 49.44% of the corresponding phenotypic variance and were all linked to RM6777. Chi-square analysis showed that the increased kernel number in Z1364 was inherited recessively by a single gene. By fine mapping, qSP1 was delimited to a 50-kb region on the short arm of chromosome 1. Based on DNA sequence, a previously uncharacterized rice homolog of Arabidopsis thaliana AT4G32551 was identified as a candidate gene for qSP1 in which mutation increases the number of spikelets and kernels in Z1364. qSP1 was expressed in all tissues, but particularly in 1-cm panicles. The expression levels of OsMADS22, GN1A, and DST were upregulated and those of LAX2, GNP1, and GHD7 were downregulated in Nipponbare. These results provide a foundation for functional research on qSP1.

Assessment of the individual and combined effects of Rht8 and Ppd-D1a on plant height, time to heading and yield traits in common wheat

Grain yield in cereal crops is a complex trait controlled by multiple genes and influenced by developmental processes and environment. Here we report the effects of alleles Rht8 and Ppd-D1 a on plant height, time to heading, and grain yield and its component traits. Association analysis and quantitative trait locus mapping using phenotypic data from 15 environments led to the following conclusions. First, both Rht8 and Ppd-D1 a reduce plant height. However, Ppd-D1 a but not Rht8 causes earlier heading.Second, both Rht8 and Ppd-D1 a promote grain yield and affect component traits. Their combined effects are substantially larger than those conferred by either allele alone.Third, promotion of grain yield by Rht8 and Ppd-D1 a is through increasing fertile spikelet number. We speculate that Rht8 and Ppd-D1 a act independently and additively in control of plant height, grain yield and yield component. Combination of the two alleles is desirable for adjusting plant height and enhancing grain yield and abiotic stress tolerance.

基于无人机影像多源信息的冬小麦生物量与产量估算

冬小麦生物量是表征产量的重要指标,通过无人机遥感技术对冬小麦生物量进行快速、无损监测能够及时掌握冬小麦生长情况,对冬小麦估产具有重要意义。基于冬小麦孕穗期、开花期和灌浆期无人机数字正射影像(DOM)的光谱信息(SIs)和纹理特征(TFs),以及数字表面模型(DSM)提取的株高(HDSM),采用多元线性回归(MLR)、偏最小二乘回归(PLSR)和随机森林(RF)方法构建了冬小麦生物量估算模型,并以此为基础进行了产量估算。结果表明,使用DOM信息进行冬小麦生物量估算时,融合SIs+TFs构建的冬小麦生物量估算模型精度优于单一光谱指数或者纹理特征构建的模型;引入HDSM信息冬小麦生物量估算模型精度得到提高,3种方法以RF方法构建的开花期模型精度最高;融合HDSM信息进行冬小麦生物量估算时,估算精度的提高以TFs+HDSM最明显。冬小麦产量早期估算中,不同生育时期实测生物量与产量拟合以对数函数模型精度最高,孕穗期、开花期和灌浆期模型R2分别为0.87、0.88和0.92。耦合生物量与产量估算最优模型进行冬小麦早期估产,灌浆期估算模型精度最高,R2、RPD和RMSE分别为0.90、2.77和244.61 kg/hm^(2)。因此,融合无人机影像DOM和DSM多源信息,集成机器学习算法,不仅可以对冬小麦生物量进行精准估算,还可以快速有效地对冬小麦产量进行早期估算,对于精准制定粮食安全政策具有重要意义。

玉米种植密度与产量研究现状与趋势

为全面深入了解玉米种植密度和产量相关研究在国内和国际的现状和发展趋势,以中国知网数据库和Web of Science核心合集数据库中2000—2022年收录有关玉米种植密度和产量领域的文献(5150篇)为样本,基于CiteSpace软件进行可视化分析。结果表明,美国居于该领域总研究量榜首,中国紧随其后,远远超过其他国家,近年来中国对该领域的研究论文数已经赶超美国,并且每年保持100篇以上的发文量。Agronomy Journal期刊发文量最多,共计230篇,在学术界影响力最大。中国学者刘鹏发文数量最多,对该领域的研究进展贡献最大,与其他作者合作也较为紧密。研究机构以高校为主,中国北方居多,各区域机构之间的合作仍有待加强。在该领域,鲜食和青贮等专用型玉米、氮水利用效率、可持续农业、机械化管理、土壤性质、产量损失、数学模型、秸秆利用等是近年来研究热点问题。

水稻抗倒伏和产量性状的相关性分析及QTLs定位

以高产品种扬稻6号和抗倒伏品种绿旱1号构建的192个重组自交系为试验材料,对8个抗倒伏性状(株高、鲜重、抗折力、基部横切面积、基部髓腔面积、基部茎壁面积、壁厚和倒伏指数)和3个产量相关性状(穗长、单穗重、有效穗数)进行相关分析和QTL定位。共定位到抗倒伏相关QTL 14个,分布在第1、2、3、5、7、8、10、12号染色体上,LOD介于3.02~14.78,加性效应值在-5.22~2.36,QTL贡献率为3.36%~20%;产量相关QTL 8个,分布在第1、3、5、12号染色体上,LOD介于3.1~9.43,加性效应值在-12.55~4.58,QTL贡献率为3.93%~14.53%。多个产量性状和抗倒伏性状之间呈显著负相关,且定位的多个QTLs呈簇出现。研究对抗倒伏性状和产量性状进行相关性分析和QTL定位,为分子设计高产、抗倒伏的优良水稻新品种提供参考。

陆地棉高密度遗传图谱的构建及产量相关性状的QTL定位

【目的】通过构建高密度SNP遗传图谱,开展棉花多群体产量相关性状的QTL定位,获得稳定性好、精确度高的QTL,为产量性状调控基因的挖掘和有效分子标记的开发提供依据。【方法】以高稳产冀丰1271为母本、优质自交系冀丰173为父本,构建包含200个单株的F_(2)群体,利用测序基因分型(genotyping by sequencing,GBS)技术开发群体的SNP标记并构建高密度遗传图谱,对F_(2)、F_(2:3)、F_(2:4)群体的衣分、子指和单铃重进行QTL定位,注释主效和稳定QTL位点内的基因并分析基因在不同组织的表达模式,筛选候选基因。【结果】通过简化基因组测序,共获得383.07 Gb数据,包括母本冀丰1271的26.93 Gb、父本冀丰173的27.30 Gb和F_(2)群体的328.84 Gb,Q30值分别为90.55%、89.95%和95.77%。在F_(2)群体中开发了1305642个SNP标记,其中,用于构建遗传图谱的aa×bb型SNP为410726个。构建了一张包含16088个SNP、总图距为4282.81 cM的高密度遗传图谱,标记间的平均距离为0.27 cM,利用共线性分析证明了图谱具有较高的质量。在3个群体中共定位到108个QTL,包括34个衣分QTL、36个子指QTL和38个单铃重QTL,其中有30个QTL与已报道QTL位置重叠或接近,78个QTL未见报道。发现10个主效QTL、16个稳定QTL,其中有5个主效QTL可在2个或3个群体中被定位到。qLP-A13-4在3个群体中均可被定位到,贡献率达到13.78%;qLP-A13-6在2个群体中被定位到,贡献率达到10.01%;qLP-D10-2在2个群体中被定位到,贡献率达到10.92%;qSI-D10-1在2个群体中被定位到,贡献率达到12.31%;qBW-D5-3在2个群体中被定位到,贡献率达到15.54%。在主效和稳定QTL位点内注释到3415个基因。通过KEGG和GO分析,注释基因主要参与植物激素信号转导、TCA循环、次生代谢物质和氨基酸生物合成、光合生物的碳固定等通路。利用TM-1和NDM8的转录组数据,发现8个基因在棉花产量相关的纤维、胚珠或种子中具有较高的表达量,可能通过调控纤维或种子的发育,影响衣分或子指,进而影响棉花单铃重和产量。【结论】构建了一张陆地棉种内高密度遗传图谱,定位了108个产量相关QTL,发现5个主效QTL可在多个群体中定位到,鉴定到8个在纤维、胚珠或种子中高效表达的候选基因。

陆地棉RIL群体产量与纤维品质性状QTL定位

棉花是世界首要的天然纤维作物,同时也是重要的蛋白和油料作物.该研究构建了一个包含184个单株的(渝棉1号×超早3号)重组近交系群体.利用SSR和SLAF-seq SNP分子标记共同构建高密度遗传图谱,结合多种环境鉴定产量和纤维品质性状表型,定位棉花产量和纤维品质性状的QTL.研究结果表明:①对8020个SSR与SNP标记进行遗传连锁分析,构建的遗传图谱共2945个位点(41 SSR和2904 SNP),遗传长度为4650.71 cM,覆盖陆地棉基因组总长的98.30%;②共定位到76个QTL,包括35个产量性状QTL,41个纤维品质性状QTL,LOD值分布在2.50~7.76之间,解释表型变异率为6.4%~23.4%;③10个QTL在两个及以上环境被检测到,为环境稳定QTL.

基于小黑麦RIL群体的草产量相关性状QTL分析

为解析调控小黑麦(Triticosecale Wittmack)草产量的遗传机制,本研究以‘甘农7号’小黑麦与‘石大1号’小黑麦构建的F 6代重组自交系(RIL)群体为材料,利用小黑麦RIL群体分子图谱,结合株高、分蘖数、穗下节间长和单株鲜重的表型值,进行QTL分析。共检测到5个株高QTL,分布在连锁群LG1,LG3,LG4,LG6上,遗传贡献率为6.56%~12.86%;4个分蘖数QTL,分布在连锁群LG2,LG5,LG6,LG7上,遗传贡献率为7.11%~12.44%;3个穗下节间长QTL,分布在连锁群LG1,LG2,LG5上,遗传贡献率为7.69%~9.63%;4个单株鲜重QTL,分布在连锁群LG2,LG5,LG6,LG7上,遗传贡献率为9.65%~13.63%。其中,株高和分蘖数的主效位点为q PH6-1和q NT5-1,表型变异解释为12.86%和12.44%;单株鲜重的主效位点为q BS2-1和q BS6-1,表型变异解释率为12.17%和13.63%,二者累加对单株鲜重具有增加效应。本研究为饲用小黑麦生物产量的精细定位和分子辅助育种提供了重要理论支撑。