Development and characterization of a novel common wheat–Mexico Rye T1DL·1RS translocation line with stripe rust and powdery mildew resistance

Rye(Secale cereale L., 2n=2x=14, RR) is a significant genetic resource for improving common wheat because of its resistance to multiple diseases and abiotic-stress tolerant traits. The 1RS chromosome from the German cultivated rye variety Petkus is critical in wheat breeding. However, its weakened disease resistance highlights the need to identify new resources. In the present study, a novel derived line called D27 was developed from common wheat and Mexico Rye.Cytological observations characterized the karyotype of D27 as 2n=42=21 Ⅱ. Genomic in situ hybridization indicated that a pair of whole-arm translocated Mexico Rye chromosomes were inherited typically in the mitotic and meiosis stages of D27. Experiments using fluorescence in situ hybridization(FISH) and gliadin electrophoresis showed that D27 lacked wheat 1DS chromosomes. They were replaced by 1RS chromosomes of Mexico Rye, supported by wheat simple-sequence repeat markers, rye sequence characterized amplified region markers, and wheat 40K SNP array analysis.The wheat 1DS chromosomes could not be detected by molecular markers and wheat SNP array, but the presence of rye 1RS chromosomes was confirmed. Agronomic trait assessments indicated that D27 had a higher tiller number and enhanced stripe rust and powdery mildew resistance. In addition, dough properties analysis showed that replacing 1DS led to higher viscosity and lower dough elasticity in D27, which was beneficial for cake making. In conclusion, the novel cytogenetically stable common wheat–Mexico Rye T1DL·1RS translocation line D27 offers excellent potential as outstanding germplasm in wheat breeding programs focusing on disease resistance and yield improvement. Additionally,it can be valuable for researching the rye 1RS chromosome’s genetic diversity.

Molecular cytogenetic analyses of two new wheat-rye 6RL translocation lines with resistance to wheat powdery mildew

Rye(Secale cereale)is a valuable gene donor for wheat improvement,especially for its resistance to diseases.Developing rye-derived resistance sources is important for wheat breeding.In the present study,two wheat-rye derivatives,designated JS016 and JS110,were produced by crossing common wheat cultivar Yangmai 23 with Pakistani rye accession W2A.Using sequential genomic in situ hybridization(GISH)and multicolor fluorescence in situ hybridization(mc-FISH),JS016 and JS110 were identified as a T6BS.6RL translocation line and a T6BS.6BL6RL translocation line,respectively.Ten newly 6RL chromosome arm-specific markers were developed and used to confirm the 6RL translocation.The wheat 55K single-nucleotide polymorphism(SNP)array further verified the molecular cytogenetic identification results above and clarified their breakpoints at 430.9 and 523.0 Mb of chromosome 6B in JS016 and JS110,respectively.Resistance spectrum and allelism test demonstrated that JS016 and JS110 possessed novel powdery mildew resistance gene(s)that was derived from the 6RL translocation but differed from Pm20.Moreover,JS016 and JS110 had better agronomic traits than the previously reported 6RL translocation line carrying Pm20.To efficiently transfer and detect the 6RL translocation from JS016 and JS110,one 6RL-specific Kompetitive allele specific PCR(KASP)marker was developed and validated in high throughput marker-assisted selection(MAS).

Development and characterization of wheat–Aegilops kotschyi 1U^(k)(1A)substitution line with positive dough quality parameters

Exploring novel high molecular weight glutenin subunits(HMW-GSs)from wild related species is a strategy to improve wheat processing quality.The objective of the present investigation was to identify the chromosomes of the wheatalien introgression line N124,derived from the hybridization between Triticum aestivum with Aegilops kotschyi,and characterize the effects on quality-related traits.Fluorescence in situ hybridization karyotypes showed that N124 is a disomic 1U^(k)(1A)substitution line.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)and reversedphase high-performance liquid chromatography verified N124 expressed two HMW-GSs of the Ae.kotschyi parent.PacBio RNA sequencing and phylogenetic analysis confirmed that the two HMW-GSs were U^(k)x and U^(k)y.Compared to the wheat parent,the substitution line had no obvious agronomic defects except fewer grains per spike but improved several major quality parameters.It can be served as a donor or bridge material for wheat quality improvement.

Fine mapping and characterization of a major QTL for grain length,QGl.cau-2D.1,that has pleiotropic effects in synthetic allohexaploid wheat

Grain size is one of the determinants of grain yield,and identifying the genetic loci that control grain size will be helpful for increasing grain yield.In our previous study,a quantitative trait locus(QTL)for grain length(GL),QGl.cau-2D.1,was identified from an F2 population developed from the cross between the natural(TAA10)and synthetic(XX329)allohexaploid wheat.In the present study,we mainly fine mapped and validated its genetic effects.To this end,multiple near-isogenic lines(NILs)were obtained through marker-assisted selection with TAA10 as the recurrent parent.The secondary populations derived from 25 heterozygous recombinants were used for fine mapping of QGl.cau-2D.1,and the allele from XX329 significantly increased GL,thousand-grain weight(TGW),total spikelet number per spike(TSN)and spike compactness(SC).Using NILs for XX329(2D+)and TAA10(2D−),we determined the genetic and pleiotropic effects of QGl.cau-2D.1.The target sequences were aligned with the wheat reference genome RefSeq v2.1 and spanned an~0.9 Mb genomic region.TraesCS2D03G0114900(ortholog of Os03g0594700)was predicted as the candidate gene based on whole-genome re-sequencing and expression analyses.In summary,the map-based cloning of QGl.cau-2D.1 will be useful for improving grain weight with enhanced GL and TSN.

Identification of Wheat-Barley 2H Alien Substitution Lines

The genetic constitution of fifteen materials derived from the cross wheat (Triticum aestivum L. cv. 'Chinese Spring') X barley (Hordeum vulgare L. cv. 'Betzes') was analyzed, and six disomic alien substitution lines were screened by GISH. The chromosome configurations in pollen mother cells at meiotic metaphase I (PMCs M I) of F, from each disomic substitution line respectively crossed with double ditelocentric lines 2A, 2B and 2D of 'Chinese Spring' were observed, and a set of wheat-barley disomic alien substitution lines 2H(A), 2H(B) and 2H(D) were obtained. The RFLP analysis with the probe psr131 on the short arm of wheat homeologous group 2 combining with four restriction enzymes were carried out. The results indicated that the probe psr131 could be used as molecular marker to tag the barley chromosome 2H. The barley chromosome 2H had good genetic compensation ability for wheat chromosomes 2B and 2D in vitality and other agronomic characters. The result of testing seed was that the wheat appearance starch quality had been changed from the half-farinaceous of 'Chinese Spring' to the half-cutin of substitution lines by transferring the barley chromosome 2H to wheat.

Preliminary Study on Inheritance of Stigma Exertion in Wheat Thermo-photo Sensitive Genic Male Sterile Line

Stigma exertion is one of the key factors for improving the outcrossing ability of wheat thermo-photo sensitive genic male sterile（TPSGMS） line. A DH population derived from K239S/K92 S was constructed to investigate the inheritance of stigma exertion. K239 S and K92 S are TPSGMS lines with higher and lower stigma exertion rates（SER）, respectively. The SERs of parents, reciprocal crosses and the DH population were evaluated for two consecutive years. The results showed that no significant difference was observed in SER between F1 s of K239S/K92 S and K92S/K239 S,implying that stigma exertion was a trait controlled by nuclear gene（s）. In the DH population, the segregation of low and high SERs fitted to a ratio of 3 ∶1 by Chisquare test, suggesting that the stigma exertion of K239 S was controlled by one pair of recessive genes. In addition, the effects of temperature and humidity on the expression of stigma exertion were also discussed.

Effect of high-molecular-weight glutenin subunit deletion on soft wheat quality properties and sugar-snap cookie quality estimated through near-isogenic lines

High-molecular-weight glutenin subunits（HMW-GSs） play a critical role in determining the viscoelastic properties of wheat dough. The HMW-GSs are encoded by Glu-A1, Glu-B1, and Glu-D1 loci on the long arms of chromosomes 1A, 1B, and 1D, respectively. In the present study, four near-isogenic lines with different HMW-GS deletions and compositions at the Glu-A1 and Glu-D1 loci in Yangmai 18 background were used for quality analysis. Deletion in Glu-D1 showed much weaker gluten quality and dough strength than null Glu-A1 genotype and wild genotype（WT）, based on the measurements of sodium dodecyl sulfate（SDS）-sedimentation, lactic acid solvent retention capacity（SRC）, gluten index, development time, stability time, and alveograph P and L values. The deletion of Glu-D1 did not significantly affect grain hardness, grain protein content, water SRC, sodium carbonate SRC, and sucrose SRC. Double null genotype in Glu-A1 and Glu-D1 and single null genotype in Glu-D1 showed significantly higher cookie diameter, crispness, and lower cookie height compared with single null genotype in Glu-A1 and WT. These indicate that the null Glu-D1 genotype is useful for improvement of biscuit quality, and use of this germplasm would be a viable strategy to develop new wheat varieties for biscuit processing.

Development and genetic analysis of wheat double substitution lines carrying Hordeum vulgare 2H and Thinopyrum intermedium 2Ai#2 chromosomes

Thinopyrum intermedium and barley are two close relatives of wheat and carry many genes that are potentially valuable for the improvement of various wheat traits. In this study we created wheat double substitution lines by hybridizing different wheat–Th. intermedium and wheat–barley disomic alien substitution lines, with the aim of using genes in Th. intermedium and barley for wheat breeding and investigating the genetic behavior of alien chromosomes and their wheat homoeologs. As expected, we obtained two types of wheat double substitution lines,2D2Ai#2(2B)2H( A) and 2A2 Ai#2(2B)2H(2D), in which different group 2 wheat chromosomes were replaced by barley chromosome 2 H and Th. intermedium chromosome 2Ai#2. The new materials were characterized using molecular markers, genomic in situ hybridization(GISH), and fluorescent in situ hybridization(FISH). GISH and FISH experiments revealed that the double substitution lines harbor 42 chromosomes including 38 wheat chromosomes, a pair of barley chromosomes, and a pair of Th. intermedium chromosomes. Analysis using specific DNA markers showed that two pairs of wheat homoeologous group 2 chromosomes in the new lines were substituted by a pair of 2H and a pair of 2Ai#2 chromosomes. Chromosome 2H showed a higher transmission rate than 2Ai#2, and both chromosomes were preferentially transmitted between generations via female gametes. Evaluation of botanic and agronomic traits demonstrated that,compared with their parents, the new lines showed similar growth habits and plant type but differences in plant height, flowering date, and self-fertility. Cytological observations using different probes suggested that the double substitution lines showed nearly normal genetic behavior before and during meiosis. The novel substitution lines can potentially be used in wheat meiosis research and breeding programs.

Identification of AFLP Markers Linked to Leaf Rust Resistance Genes Using Near Isogenic Lines of Wheat

The present investigation was undertaken to find molecular markers linked to leaf rust resistance genes, Lr9 and Kharchia local mutant KLM4-3B. Preliminary AFLP analysis was carried out with different stocks, a survey of primer combinations with different selective nucleotide indicated that for each primer combination, the number of scorable loci ranged from 34 to 123. Only a limited primer combination used in the set of parental and near isogenic lines showed a high level of polymorphism for AFLP marker. Putative AFLP marker were found to be linked to Lr9, Lr19 and KLM4-3B. The alien genes were readily identified.

A genetic evidence of chromosomal fragment from bridge parent existing in substitution lines between two common wheat varieties

Locating of important agronomic genes onto chromosome is helpful for efficient development of new wheat varieties. Wheat chromosome substitution lines between two varieties have been widely used for locating genes because of their distinctive advantages in genetic analysis, compared with the aneuploid genetic materials. Apart from the substituted chromosome, the other chromosomes between the substitution lines and their recipient parent should be identical, which eases the gene locating practice. In this study, a set of chromosome substitution lines with cv. Wichita （WI） as the recipient parent and cv. Cheyenne （CNN） as the donor parent were studied for the composition of high molecular weight glutenin subunits （HMW-GS） as well as a range of agronomic important traits. Results revealed that the substitution lines of WI（CNN5D）, WI（CNN6A） and WI（CNN7B） had higher plant heights than the two parents of WI and CNN, and WI（CNN3D） had later maturity than the parents. By sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE） and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF-MS） analysis, a substitution line WI（CNN5B） was found to contain different HMW-GS patterns from its two parents, in which 1 By9 was replaced by 1 By8 on chromosome 1BL. Simple sequence repeat （SSR） analysis confirmed that the variation on 1BL in WI（CNN5B） was originated from Chinese Spring （CS）. It is concluded that chromosomal fragments from bridge material and donor parent were quite often retained in intracultivaral chromosome substitution lines except the substituting chromosomes.

Introgression of chromosome 6PL terminal segment from Agropyron cristatum to increase both grain number and grain weight in wheat

Agropyron cristatum(2n=4x=28,PPPP),which harbours many high-yield and disease-resistance genes,is a promising donor for wheat improvement.Narrow genetic diversity and the trade-off between grain weight and grain number have become bottlenecks for increasing grain yield in wheat.In this study,a novel translocation line,WAT650l,was derived from the chromosome 6P addition line 4844–12,which can simultaneously increase both grain number per spike(GNS)and thousand-grain weight(TGW).Cytological analysis and molecular marker analysis revealed that WAT650l was a 5BL.5BS-6PL(bin 12–17)translocation line.Assessment of agronomic traits and analysis of the BC4F2 and BC5F2 populations suggested that the 6PL terminal chromosome segment in WAT650l resulted in increased grain number per spike(average increased by 14.07 grains),thousand-grain weight(average increased by 4.31 g),flag leaf length,plant height,spikelet number per spike and kernel number per spikelet during the two growing seasons of 2020–2021 and 2021–2022.Additionally,the increased GNS locus and high-TGW locus of WAT650l were mapped to the bins 16–17 and 12–13,respectively,on chromosome 6PL by genetic population analysis of three translocation lines.In summary,we provide a valuable germplasm resource for broadening the genetic base of wheat and overcoming the negative relationship between GNS and TGW in wheat breeding.

Characterization of Newly Developed Wheat/Barley Introgression Lines in Respect of Aluminium Tolerance

The Al tolerance of newly developed wheat/barley disomic addition, substitution and translocation lines carry chromosomes of three different barley cultivars was evaluated by comparing the root growth in solution containing 75 μM AlCl3 at pH 4.0 to that of known Al-tolerant and sensitive wheat genotypes. The wheat Asakaze komugi, barley Manas cultivars and their hybrid derivatives were found to have high levels of Al tolerance. The wheat line Mv9kr1, barley cultivar Igri and progenies of the hybrids were sensitive to Al. In most cases, the Al tolerance of the wheat/barley introgression lines derived from Al-sensitive wheat Mv9kr1 and barley Betzes with moderate Al tolerance was similar to that of the wheat parents, but the 2DS.2DL-1HS translocation line of Mv9kr1/Betzes exhibited more intensive root growth, while accumulating less Al than the parental lines. This indicates that either the lack of the distal part of chromosome 2DL or the presence of the distal part of 1HS improved the Al tolerance level.

The Study of the Anatomical Features of Wheat Grains in the Species T. dicoccum Schuebl,, Sort Mironovskaya-808 and AIIoplasmatic Lines （Their Interspecific Hybrids F9）

In cross sections by microscopic studies have examined the features of the shell thickness grains, cells, aleuronic layer and endosperm in the species T. dicoccum Schuebl., sorts Mironovskaya-808 and their interspecific hybrids F9 （alloplasmatic lines）. The result of studies showed the specific and varietal differences, and differences in hybrid plants on linear parameters size grains, the degree of specificity of the shells grains of wheat and identified species and varietal differences as well as differences among hybrids in the linear dimensions of the cells of the aleuronic layer. It is shown that among the studied forms of wheat allocated species T. dicoccum Shuebl. and the lines D-N-05, D-F-05 and D-40-05-KhNA with relatively large grains, a well-developed endosperm, most of thin shells and large grain aleurone layer cells. They are of most interest for further breeding research in terms of nutritional value.

小麦光温敏核雄性不育系BS366和BS1086杂种一代结实率研究

为了解小麦光温敏核雄性不育系BS366和BS1086的育性恢复状况,评估恢复系人工定向改良对其恢复能力的效果,在不育生态区对以55份定向改良的恢复系和33份非改良恢复系(常规小麦)为父本配制的杂种一代的结实率进行了分析。结果表明,BS366和BS1086杂种一代结实率变化范围为15.42%~140.34%和20.28%~119.07%(国际法),平均结实率分别为73.02%和72.21%,二者差异不显著,说明2份母本的育性恢复能力差异不显著。BS366和BS1086杂种一代结实率主要分布于40%~110%和60%~100%间,BS1086杂种一代结实率分布更为集中。BS366和BS1086与改良父本的杂种一代平均结实率分别为84.45%和78.97%,与非改良父本的杂种一代平均结实率分别为53.97%和60.95%,改良父本的平均恢复力高于非改良父本,表明定向改良有利于提高恢复系的恢复力。BS366和BS1086与相同父本的杂种一代结实率差异在-41.66%~61.93%之间,表明相同父本对不同母本的育性恢复力存在差异。BS366和BS1086与相同改良父本的杂种一代中有61.82%的结实率差异分布于-10%~20%之间,与相同非改良父本的杂种一代中有51.52%的结实率差异在-30%~0%之间,表明同一改良父本对不同母本的育性恢复力差异小于非改良父本。BS366与14份父本、BS1086与7份父本的杂种一代结实率高于对照,其中父本14YH261、14YH551、SD036与2份母本杂种一代的结实率均高于对照,说明具有可用恢复力的父本不仅数量极少,而且对不同母本的恢复力存在较大差异。杂种一代主茎穗的平均结实率极显著大于分蘖穗。因此,建议对不同母本分别开展强恢复力的恢复系筛选,并以中选强恢复系为亲本进行定向改良,有效增加杂种一代结实率达对照水平的组合数量,为获得更多强优势杂交组合奠定基础。

旱地小麦区试品系中抗旱高产相关基因的KASP标记检测

利用分子标记检测小麦区试品系,明确其优异等位基因组成,有利于进一步精准改良利用。分析KASP标记检测中存在的问题,有助于促进分子育种应用。以山东省2021—2022年小麦旱地区试24份参试品系为材料,利用32个抗旱高产相关基因的KASP标记,分析KASP标记检测中存在的异常结果和材料的优异等位基因利用情况。结果表明,未知基因型产生的主要原因是KASP反应失败或非特异扩增。混合DNA样品检测结果为杂合的主要原因是单株间基因型不一致,次要原因是错误分型。32个KASP标记中,14个标记的优异等位基因检出率超过83%,表明这些基因在育种中已经得到有效利用;17个标记的优异等位基因检出率低于50%,其中,WRKY51-2B、AX-95025477-7B、SnRK2.4A3、TaMoc-2433和NCED15个标记的优异等位基因未检出,表明这些基因在育种中利用较少,可通过分子标记辅助选择开展遗传改良。24份材料中,HQ04携带20个优异等位基因,是数量最多的,可作为基因供体用于育种。利用KASP标记开展辅助选择定向精准提高优异等位基因在小麦育种中的利用率仍有可为。

基于GT双标图对小麦新品系的分类评价

为了从产量、品质方面准确评价旱肥地试验小麦新品系,以2020—2021年连续2年参加国家黄淮冬麦区旱地组多点比较试验的26份新品系为材料,应用多元统计方法分析了大田条件下2年间产量和品质性状的变化。结果表明:26份品系的产量和品质性状2年变异系数分别为2.0%~74.2%和2.1%~95.1%,变异较大,变异系数大小顺序依次为稳定时间>湿面筋含量>蛋白质含量>吸水率=单位面积产量>容重;相关分析表明,2年产量与品质性状存在负相关关系,稳定时间均与蛋白质含量、吸水量正相关,稳定时间与产量负相关,其中稳定时间与蛋白质含量相关系数均较高。在相关分析的基础上,采用聚类分析方法将2年中26份小麦参试品系聚为4类,并在主成分品种、性状(genotype by trait,GT)双标图(biplot)和聚类图中进行展示,聚类结果与新品系的实际表现一致,其中‘泰科麦4835’‘洛旱35’‘农大162’‘山农611436’连续2年划为同一类型,表现为产量较高、品质优良。该研究结果可为参试新品系的合理评价和推广应用提供理论依据。

新疆冬麦区AL型三系杂交小麦亲本配合力、杂种优势和聚类分析

为了解新疆AL型三系杂交小麦亲本间配合力及其杂种优势关系,利用稳定不育系8份,恢复力强的恢复系9份,按照NCⅡ不完全双列杂交(8×9)设计配制72个F 1杂交组合,对亲本及杂交组合的7个农艺性状进行配合力效应和杂种优势分析,再根据亲本性状和一般配合力划分杂种优势类群。结果表明,三系小麦杂交组合中普遍存在产量和产量性状杂种优势,针对强优势组合的亲本选择,双亲之一一般配合力(GCA)或双亲GCA之和为正值且相对较大;相关性分析表明,中亲优势与父本和母本GCA值之和呈极显著正相关,父本和母本的GCA相关性大于特殊配合力(SCA)相关性。针对6个性状的GCA效应值和性状表型值分别进行聚类分析表明,配合力距离远的亲本组配可能出现强优势杂交组合的几率较大,性状表型值距离较远的两个亲本同一性状之间的优势互补也可以在后代中表现出较强的杂种优势。将17个亲本划分为4个和5个类群,为后续AL型杂交小麦强优势杂交组合的配制提供了依据。

安农1687抗条锈病候选基因TraesCS2A01G070700鉴定与分析

为了探索安农1687对于条锈病抗性的遗传机理,加快安农1687小麦品种的推广,为小麦新品种的遗传改良提供参考,减少小麦条锈病对于我国小麦生产安全的危害。以安农1687(安农1687是由安农1106和西农822杂交选育的,对生理小种CYR32具有抗性的半冬性小麦品种)及其姊妹系和亲本为材料,利用小麦55K SNP芯片对安农1687及其双亲和姊妹系进行全基因组扫描,同时利用生理小种CYR32对安农1687及其姊妹系进行接种和鉴定,并在成株期统计其抗条锈病等级,综合接种及田间表型对小麦品系抗条锈病进行评价。鉴定结果显示,安农1687和5个姊妹系(系24、系26、系28、系30、系140)为中抗条锈病,2个姊妹系(系89和系105)为中感条锈病。利用安农1687及其姊妹系间的基因组差异信息,发现差异SNP位点富集在2A染色体短臂的31~37 Mb区间上,说明2A染色体可能存在某个或某些基因导致了这样的结果。为了排除其他抗条锈病基因的干扰,对亲本及2A染色体上携带的已知抗条锈病基因进行验证,结果表明,安农1687的2A染色体短臂的31~37 Mb区间可能存在一个新抗条锈病基因。通过试验和生物信息学分析发现,该区段内的TraesCS2A01G070700基因在抗感品系的NBS结构域上存在差异,感病品系中NBS结构域有3个错义突变,推测TraesCS2A01G070700为安农1687抗条锈病候选基因。

济麦44/济麦229重组自交系群体籽粒蛋白质含量QTL分析

小麦籽粒蛋白质含量与面团流变学特性及加工特性的关系密不可分。本研究在2020—2021年济南试验基地(E1)及2021—2022年济南试验基地(E2)和济阳试验基地(E3)三个环境下,以“济麦44×济麦229”构建的包含285个家系的重组自交系群体(F2∶6RILs)为材料,利用小麦55K SNP芯片构建高密度遗传连锁图谱,对籽粒蛋白质含量进行QTL分析。结果共筛选到2344个SNP标记用于构建遗传连锁图谱,图谱总长度3349.95 cM,平均标记密度为1.43 cM/标记。通过对籽粒蛋白质含量的QTL分析,共检测到18个籽粒蛋白质含量相关QTL,分布在1A、1B、2B、3D、4B、4D、5A、5B、5D、7A、7B共11条染色体上。Qpc.saas.4B-1在E1、E2和E3三个环境和BLUE(最佳线性无偏估计)值中均被稳定检测到,可以解释3.26%~23.79%的表型变异。Qpc.saas.4D和Qpc.saas.5A在两个环境和BLUE值中被检测到,分别解释2.42%~11.18%和2.48%~5.47%的表型变异,且Qpc.saas.4D与小麦矮秆基因Rht-D1b物理位置重合。本研究中检测到的QTL新位点Qpc.saas.4B-1、Qpc.saas.4D和Qpc.saas.5A是控制籽粒蛋白质含量的主效基因,具有高表型变异解释率。本研究结果可为小麦品质育种提供分子标记及理论参考。

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。