Cotton is a vital economic crop and reserve material and a pioneer crop planted on saline-alkaline soil. Improving the tolerance of cotton to saline alkaline environments is particularly important. Salt-tolerant and salt-sensitive cotton plants at the three-leaf stage were subjected to 200 mM NaCl stress treatment, thereafter, microstructural observations beside physiological and biochemical analyses were performed on cotton leaves at 0 h (CK), 48 h (NaCl) and re-watering (RW) for 48 h. Salt stress altered microstructural observations and physiological and biochemical in ST and SS (p < 0.05). After re-watering, ST recovered fully, while SS sustained permanent oxidative and structural damage, indicating distinct salt tolerance. Transcriptome analysis was performed on cotton leaves under salt stress and re-watering conditions. KEGG analysis revealed that the response of cotton to salt stress and its adaptation to re-watering may be related to major protein families such as photosynthesis (ko 00195), photosynthesis-antenna protein (ko 00196), plant hormone signal transduction (ko 04075), starch and sucrose metabolism (ko 00500), and porphyrin and chlorophyll metabolism (ko 00860). A gray coexpression module associated with cotton restoration under salt stress was enriched according to WGCNA. Salt stress did not only affect the physiological and biochemical levels of cotton but also induced structural changes in cells and tissues. Re-watering was relatively effective in stabilizing the physiological and biochemical parameters, as well as the leaf microstructure, of cotton plants under salt stress. WGCNA revealed enriched gray coexpression modules related to the recovery of cotton plants under salt stress, and screening of the pivotal genes in the gray module revealed five critical hubs, namely, GH_A01G1528, GH_A08G2688, GH_D08G2683, GH_D01G1620 and GH_A10G0617. Overall, our findings can provide new insights into enhancing cotton salt tolerance and exploring salt tolerance genes in cotton,including screening cotton genetic resources using those potential responsive genes. This study provides a theoretical basis for further exploration of the molecular mechanism of cotton salt tolerance and genetic resources for breeding salt-tolerant cotton.

Leaf colour mutants are ideal germplasm resources for investigating the mechanisms of chlorophyll (Chl) synthesis, chloroplast development and photosynthesis. In this study, we obtained a yellow-leaf mutant, designated SN288-2. The variant presented a yellow-leaf phenotype and halted the development of chloroplasts at the seedling stage, with reduced accumulation of Chl. The yellow-leaf phenotype reverted to the normal phenotype in the wheat revival stage. In addition, the ratio of the crucial Chl precursors protoporphyrin IX (Proto IX) and Mg-protoporphyrin IX (Mg-Proto IX) was relatively high in yellow leaves. Bulked segregant analysis sequencing (BSA-Seq) revealed that the aberrant phenotype was controlled by two recessive genes located on chromosomes 7A and 7D, designated Y1-7A and Y2-7D, respectively. Subsequent research focused on Y1-7A. We identified TraesCS7A03G1163900 as a viable candidate for Y1-7A, encoding a major subunit of Mg-chelatase that is essential for Chl synthesis. Whole-genome resequencing and Sanger sequencing revealed a 5.3 kb deletion on the long arm of chromosome 7A in SN388-2 that encompasses the entire Y1-7A sequence. Quantitative real-time PCR (qRT-PCR) revealed that the Y1-7A gene was predominantly expressed in green tissues and that the encoded protein was localized within the chloroplast. Moreover, weighted gene coexpression network analysis (WGCNA) revealed a gene module associated with leaf development and Chl content restoration. Consequently, these results provide a new theory regarding the regulation of Chl synthesis and chloroplast development. Overall, the loss of Y1-7A impaired the function of Mg-chelatase and blocked the conversion of Proto IX to Mg-Proto IX.

Stripe rust, induced by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive fungal diseases of wheat worldwide. Thinopyrum ponticum, a significant wild relative for wheat improvement, exhibits innate immunity to this disease. To transfer the stripe rust resistance gene from Th. ponticum to wheat, two translocation lines, SN21171 and SN52684, were produced through distant hybridization techniques. Disease evaluation results showed that these two lines were immune to Pst species CYR32 at the adult plant stage. Molecular cytogenetic analyses and specific intron-targeting markers amplification results revealed that SN21171 and SN52684 harbor several T3Eb-3DS·3DL and T1Eb-1BS·1BL translocation chromosomes. Furthermore, the comparison of the chromosome karyotype from two translocation lines and their recurrent parent YN15, revealed that structural variation occurred in chromosomes 2A, 5A, 2B, 4B, 5B, and 6B in SN21171 and chromosomes 5A, 3B, 4B, 5B, 6B, and 7B in SN52684. Agronomic trait assessments uncovered advantageous properties in both lines, with SN21171 matching the recurrent parent and SN52684 exhibiting elevated higher grain number per main spike and increased thousand grain weight. These two translocation lines and specific markers may apply to wheat stripe rust-resistance breeding.

Abstract Background Developing and enriching genetic resources plays important role in the crop improvement. The flag leaf affects plant architecture and contributes to the grain yield of wheat (Triticum aestivum L.). The genetic improvement of flag leaf traits faces problems such as a limited genetic basis. Among the various genetic resources of wheat, Thinopyrum intermedium has been utilized as a valuable resource in genetic improvement due to its disease resistance, large spikes, large leaves, and multiple flowers. In this study, a recombinant inbred line (RIL) population was derived from common wheat Yannong15 and wheat-Th. intermedium introgression line SN304 was used to identify the quantitative trait loci (QTL) for flag leaf-related traits. Results QTL mapping was performed for flag leaf length (FLL), flag leaf width (FLW) and flag leaf area (FLA). A total of 77 QTLs were detected, and among these, 51 QTLs with positive alleles were contributed by SN304. Fourteen major QTLs for flag leaf traits were detected on chromosomes 2B, 3B, 4B, and 2D. Additionally, 28 QTLs and 8 QTLs for flag leaf-related traits were detected in low-phosphorus and drought environments, respectively. Based on major QTLs of positive alleles from SN304, we identified a pair of double-ended anchor primers mapped on chromosome 2B and amplified a specific band of Th. intermedium in SN304. Moreover, there was a major colocated QTL on chromosome 2B, called QFll/Flw/Fla-2B, which was delimited to a physical interval of approximately 2.9 Mb and contained 20 candidate genes. Through gene sequence and expression analysis, four candidate genes associated with flag leaf formation and growth in the QTL interval were identified. Conclusion These results promote the fine mapping of QFll/Flw/Fla-2B, which have pleiotropic effects, and will facilitate the identification of candidate genes for flag leaf-related traits. Additionally, this work provides a theoretical basis for the application of Th. intermedium in wheat breeding.

Rye (Secale cereale L.) genes, which contribute to the tertiary gene pool of wheat, include multiple disease resistance genes useful for the genetic improvement of wheat. Introgression lines are the most valuable materials for wheat breeding because of their small alien segments and limited or lack of linkage drag. In the present study, wheat-rye derivative lines SN21627-2 and SN21627-6 were produced via distant hybridization. A genomic in situ hybridization analysis revealed that SN21627-2 and SN21627-6 lack alien segments, while a multi-color fluorescence in situ hybridization analysis detected structural changes in both introgression lines. At the seedling and adult plant stages, SN21627-2 and SN21627-6 were highly resistant to stripe rust and powdery mildew. Primers for 86 PCR-based landmark unique gene markers and 345 rye-specific SLAF markers were used to amplify SN21627-2 and SN21627-6 genomic DNA. Eight markers specific to rye chromosome 2R were detected in both introgression lines, implying these lines carry chromosome 2R segments with genes conferring stripe rust and powdery mildew resistance. Therefore, SN21627-2 and SN21627-6 are resistant to more than one major wheat disease, making them promising bridging parents for breeding disease-resistant wheat lines.

SummaryThe biotrophic fungal pathogenBlumeria graminisf. sp.tritici(Bgt) is a crucial factor causing reduction of global wheat production. Wild wheat relatives, e.g.Thinopyrum intermedium,is one of the wild-used parents in wheat disease-resistant breeding. FromT.intermediumline, we identified the aspartic acid protein gene,TiAP1, which involved in resistance againstBgt. TiAP1 is a secreted protein that accumulates in large amounts at the infection sites of powdery mildew and extends to the intercellular space. Yeast two-hybrid showed that it interacted with the chitin deacetylase (BgtCDA1) ofBgt. The yeast expression, purification, andinvitrotest confirmed the chitin deacetylase activity of BgtCDA1. The bombardment and VIGS mediated host-induced gene silencing showedBgtCDA1promotes the invasion ofBgt. Transcriptome analysis showed the cell wall xylan metabolism, lignin biosynthesis-related, and defence genes involved in the signal transduction were upregulated in the transgenicTiAP1wheat induced byBgt. The TiAP1 in wheat may inactivate the deacetylation function of BgtCDA1, cause chitin oligomers expose to wheat chitin receptor, then trigger the wheat immune response to inhibit the growth and penetration ofBgt, and thereby enhance the tolerance of wheat to pathogens.

Nitrogen is an important nutrient for crop growth and development. Plant height-related traits can be affected by nitrogen supplementation. In this study, we performed a genome-wide association study (GWAS) on plant height, spike length, length of different internodes, and lodging resistance strength at the grain-filling stage based on wheat local varieties subjected to low nitrogen and normal (CK) treatments. GWAS analysis showed that a total of 86 quantitative trait locus (QTLs) were detected, including 13 QTLs for plant height, 10 QTLs for spike length, 19 QTLs for the length of the first internode from the top of the plant, 6 QTLs for the second internode length, 11 QTLs for the third internode length, 13 QTLs for the fourth internode length, and 14 QTLs for the fifth internode length. Compared to the CK treatment, the plant height, spike length, and fourth and fifth internode lengths were significantly affected by the low nitrogen treatment. A total of 18 QTLs responding to low nitrogen level were detected, including three QTLs for the fourth internode length detected on 3A, 6A, and 6D chromosomes, eleven QTLs for the fifth internode length on 1A, 1B, 1D, 2A, 2B, 3A, 3B, 4A, 5B and 7B chromosomes, one QTL for spike length on 3A chromosome, and one QTL for plant height on 5B chromosome. These QTLs will enhance our understanding of the genetic basis of plant height responses to nitrogen deficiency and will benefit genetic reactions to nitrogen fertilization.

Powdery mildew is one of the most devastating foliar diseases in wheat production. The wild relative Thinopyrum ponticum (2n = 10x = 70) has been widely used in wheat genetic improvement due to its superior resistance to both biotic and abiotic stresses. In the present study, two wheat-Th. ponticum introgression lines named SN0293-2 and SN0293-7 were developed from the progenies of a cross between the octoploid Trititrigia SNTE20 and common wheat, including the elite cultivar Jimai 22. They had a novel powdery mildew resistance gene (temporarily named PmSN0293) putatively from Th. ponticum pyramided with Pm2 and Pm52, exhibiting excellent Pm resistance at both the seedling and adult stages. Sequential GISH-FISH detected no signal of Th. ponticum in these two lines but a pair of T1BL·1RS in SN0293-2. Chromosomal structural variations were also observed obviously in SN0293-2 and SN0293-7. Through the Wheat 660K SNP array, 157 SNPs, 134 of which were on 6A, were found to be specific to Th. ponticum. Based on the data combined with DNA re-sequencing, seven specific markers, including one CAPS marker on 2B and six CAPS and Indel markers on 6A, were developed, confirming their wheat-Th. ponticum introgression nature. Furthermore, the two lines displayed positive plant height and produced more kernels and higher 1,000-grain weight. Excellent resistance with desirable agronomic traits makes them valuable in wheat breeding programs.

Auxin is an important endogenous hormone in plants. The YUCCA gene encodes a flavin monooxygenase, which is an important rate-limiting enzyme in the auxin synthesis pathway and involved in the regulation of plant growth and development. In the study, we identified 63 wheat TaYUCCA genes; among them, some genes appeared in clusters. By constructing phylogenetic trees, we found that the TaYUCCA genes could be divided into six groups. In the WheatExp database, there were 22 differential expressed TaYUCCA genes, among which the TaYUCCA10 gene was abundantly expressed in the endosperm and medium milk stage, the TaYUCCA2 gene was abundantly expressed in the roots of three leaves and meiosis and transfer cells at 20 days post anthesis and the others 16 TaYUCCA genes had different expression level at different developmental stages in wheat, and there were 15 TaYUCCA genes induced by drought and heat stress, among which the TaYUCCA2-D, TaYUCCA3-B, and TaYUCCA9-D might be upregulated induced by drought stress, TaYUCCA10.1 might be upregulated induced drought and heat stress, TaYUCCA6-A was upregulated induced both drought and heat stress and the others 9 TaYUCCA genes were downregulated induced by drought and heat stress. Transcriptome and qRT-PCR analysis showed that TaYUCCA7-A was upregulated significantly after induced by powdery mildew. The comprehensive annotation and expression profiling of the TaYUCCA genes in this study enhanced our understanding of TaYUCCA family gene expression in wheat growth and development and laid the foundation for the further study of TaYUCCA gene mechanism.

为了解中国不同麦区小麦种质资源籽粒脂肪氧化酶(lipoxygenase,LOX)活性相关基因TaLox-Bl的差异和分布,利用小麦4B染色体上的功能标记LOX16和LOX18对7个麦区的436份种质资源进行分子检测.结果表明:在供试材料中共检测到3种TaLox-B1基因等位变异类型,分别为TaLox-B1a(与高LOX活性相关)、TaLox-B1b(与低LOX活性相关)和杂合型,其频率分别为19.0％、70.4％和10.6％.小麦LOX活性基因不同变异类型在各生态区的分布存在明显差异:基因型TaLox-B1a在黄淮冬麦区、北部冬麦区和长江中下游冬麦区分布较多,其比例分别为21.1％、19.8％和17.6％;基因型TaLox-B1b在西南冬麦区和长江中下游冬麦区分布较多,比例分别为87.9％、72.5％;杂合型仅存在于北部冬麦区、黄淮冬麦区与长江中下游冬麦区,比例分别为14.2％、12.4％和9.8％.利用标记LOX16和LOX18对53个自选高代品系进行分子检测,发现自选品系仅有TaLox-B1b与杂合型两种基因型,其中基因型TaLox-B1ab有32个,比例为60.4％.采用分子标记辅助选择,有利于快速鉴定小麦籽粒LOX活性,加速LOX的遗传改良和新品种选育.

Background Thinopyrum intermedium (2n = 6x = 42) is an important wild perennial Triticeae species exhibiting many potentially favorable traits for wheat improvement. Wheat- Th . intermedium partial amphiploids serve as a bridge to transfer desirable genes from Th . intermedium into common wheat. Results Three octoploid Trititrigia accessions (TE261–1, TE266–1, and TE346–1) with good resistances to stripe rust, powdery mildew and aphids were selected from hybrid progenies between Th . intermedium and the common wheat variety ‘Yannong 15’ (YN15). Genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH) and multicolor GISH (McGISH) analyses demonstrated that the three octoploid Trititrigia possess 42 wheat chromosomes and 14 Th. intermedium chromosomes. The 14 alien ( Th. intermedium ) chromosomes belong to a mixed genome consisting of J-, J S - and St-genome chromosomes rather than a single J, J S or St genome. Different types of chromosomal structural variation were also detected in the 1A, 6A, 6B, 2D and 7D chromosomes via FISH, McGISH and molecular marker analysis. The identity of the alien chromosomes and the variationes in the wheat chromosomes in the three Trititrigia octoploids were also different. Conclusions The wheat- Th. intermedium partial amphiploids possess 14 alien chromosomes which belong to a mixed genome consisting of J-, J S - and St- chromosomes, and 42 wheat chromosomes with different structural variations. These accessions could be used as genetic resources in wheat breeding for the transfer of disease and pest resistance genes from Th. intermedium to common wheat.

In order to identify QTLs for 1000-grain weight and its main component traits in wheat, a high-density genetic link map was constructed using a F 8:9 recombined inbred line (RIL) population as material and exploiting the single nucleotide polymorphism (SNP) as well as PCR-based molecular markers, and to go a step further, QTL mapping for 1000-grain weight, grain length, and grain width in wheat was conducted. The linkage map was composed of 1257 loci formed by the 3916 markers, including 143 SSR markers and 3773 SNP markers, which were distributed on 22 chromosomes (2A chromosome formed a break point) with the total length of 2291.6 cM and the average genetic distance between loci of 1.82 cM. A total of 41 qualitative trait loci (QTLs) on 19 chromosomes were detected, with contributions to phenotypic variance ranged from 3.59–58.49% for each QTL. Among these QTLs, two were detected in four environments, six in three environments, and 14 in two environments. Fifteen important loci with multi-effect were mapped on 9 chromosomes 1B, 2B, 3A, 4B, 5A, 5B, 6A, 7A, and 7B, involving 37 QTLs that accounted for 90.2% of total numbers of QTLs detected. Of these 15 loci, including one on chromosome 7A flanked by the markers Tdurum_contig77759_5 and BS00062425_51 , which consisted of QTLs controlling TGW, GL, and GW and explained 4.2 to 58.49% of the phenotypic variation in these traits. Thus, the chromosome intervals of the 15 loci were important areas controlling the expression of 1000-grain weight and its main component traits in wheat.

Thinopyrum ponticum (2n = 10x = 70) is a wild relative of wheat with high tolerance to both biotic and abiotic stresses; it has been wildly used in wheat genetic improvement. A disomic substitution line named SN19647 was derived from a cross between Triticum aestivum and the wheat-Th. ponticum partial amphiploid SNTE20 (2n = 8x = 56). It was evaluated for disease resistance and characterized via sequential fluorescence in situ hybridization (FISH)-genomic in situ hybridization (GISH) and molecular markers. The results showed that SN19647 carried resistance to both powdery mildew and leaf rust. It contained 42 chromosomes with a pair of wheat chromosome 1B replaced by a pair of J(S) chromosomes from Th. ponticum. In addition to chromosomal substitution events, structural variation also occurred on wheat chromosomes 2A, 5A, 6B, and 7B. Based on marker analysis, 19 markers specific to the J(S) chromosome were obtained, of which seventeen markers belonged to homoeologous group one. These results indicated that SN19647 was a 1J(S) (1B) substitution line. Compared with the known 1J(S) (1D) substitution line CH10A5, it was found that 17 markers generated different specific bands to Th. ponticum, confirming the novelty of the 1J(S) chromosome in SN19647. Therefore, SN19647, resistant to powdery mildew and leaf rust, was a novel 1J(S) (1B) substitution line that can be used in wheat genetic improvement.

Thinopyrum intermedium has been used as a resource for improving resistance to biotic and abiotic stresses and yield potential in common wheat. Wheat line SN304 was derived from a cross between common wheat cultivar Yannong 15 and Th. intermedium. Genomic in situ hybridization (GISH) produced no hybridization signal in SN304 using Th. intermedium genomic DNA as a probe, but fluorescence in situ hybridization (FISH) using oligonucleotides AFA-3, AFA-4, pAs1-1, pAs1-3, pAs1-4, pAs1-6, pSc119.2-1, and (GAA)10 as probes detected hybridization signals on chromosomes 2A, 7A, 2B, 3B, 6B, and 7B in SN304 that differed from Yannong 15. Results of specific markers also indicated that there were Th. intermedium chromatin introgressions on different chromosomes in SN304. In a hydroponic culture experiment, SN304 not only produced more biomass and higher stem and leaf dry weight but also accumulated more phosphorus than Yannong 15 under phosphorus-deficiency stress. Moreover, SN304 produced a lower pH and released more organic acids, especially oxalic acid, than Yannong 15, which suggests that SN304 exudates enabled more absorbance of P than Yannong 15 under comparable conditions. The results indicate that SN304 is a wheat-Th. intermedium introgression line with tolerance to phosphorus-deficiency stress.

Awn is one of wheat morphological characteristics and acts as a highly effective organ for photosynthesis in wheat. Variation in awn length is controlled primarily by three major genes, most commonly the dominant awn suppressor Tipped1 (B1). So far, the function of B1 is not well understood. In this paper, we identified a pair of near-isogenic lines (NILs) containing different awn inhibition gene B1 alleles and observed microstructures and ultra-microstructure of their awns. The typical awns differences between the NILs represented by the cross-sectional area and chloroplasts number. Long awn line had a larger cross- sectional area, and more cells in various parts of tissues, especially the cells containing more and larger chloroplasts, which could attribute to a strong cytological basis for photosynthesis. The results may suggest that the gene has pleiotropic effects in the control development of awn tissue structure and grain yield.

KEY MESSAGE:Present study revealed that specific expression of TaYUC10.3 in wheat young seeds could increase the content of auxin, and protein. Auxin is a vital endogenous hormone in plants, which is involved in the regulation of various physiological and biochemical processes in plants. The flavin-containing monooxygenase encoded by the YUCCA gene is a rate-limiting enzyme in the tryptophan-dependent pathway of auxin synthesis. TaYUC10.3 was identified, cloned and found that it was abundantly expressed in wheat young seeds. In this study, a seed-specific expression vector of TaYUC10.3 was constructed with the promoter of 1Bx17 glutenin subunit gene and transformed wheat using the particle bombardment method. The quantitative RT-PCR showed that TaYUC10.3 was expressed in a large amount in young seeds of the transgenic lines. Plant hormone-targeted metabolomics showed that the auxin content of the transgenic lines was significantly increased compared with controls. The GC / MS non-targeted metabolite multiple statistical analyses showed that the variable importance in projection (VIP) of tryptophan reduced in the transgenic lines. Simultaneously, the VIP of indole acetic acid increased. The precursor amino acids for synthesizing some proteins and carbohydrates were upregulated in the transgenic lines. Subsequently, it was found that the protein content of the seeds of the transgenic TaYUC10.3 wheat was significantly higher than that of the control. The wet gluten content and sedimentation value of the transgenic TaYUC10.3 wheat were also high. This result indicated that TaYUC10.3 might participate in auxin synthesis and affects the protein content of wheat seeds.

Wheat (Triticum aestivum) is a major staple food crop worldwide. Genetic dissection of important agronomic traits is essential for continuous improvement of wheat yield to meet the demand of the world's growing population. We conducted a large-scale genome-wide association study (GWAS) using a panel of 768 wheat cultivars that were genotyped with 327 609 single-nucleotide polymorphisms generated by genotyping-by-sequencing and detected 395 quantitative trait loci (QTLs) for 12 traits under 7 environments. Among them, 273 QTLs were delimited to ≤1.0-Mb intervals and 7 of them are either known genes (Rht-D, Vrn-B1, and Vrn-D1) that have been cloned or known QTLs (TaGA2ox8, APO1, TaSus1-7B, and Rht12) that were previously mapped. Eight putative candidate genes were identified for three QTLs that enhance spike seed setting and grain size using gene expression data and were validated in three bi-parental populations. Protein sequence analysis identified 33 putative wheat orthologs that have high identity with rice genes in QTLs affecting similar traits. Large r2 values for additive effects observed among the QTLs for most traits indicated that the phenotypes of these identified QTLs were highly predictable. Results from this study demonstrated that significantly increasing GWAS population size and marker density greatly improves detection and identification of candidate genes underlying a QTL, solidifying the foundation for large-scale QTL fine mapping, candidate gene validation, and developing functional markers for genomics-based breeding in wheat.

Abstract Background Lesion-mimic and premature aging (lmpa) mutant lmpa1 was identified from the ethyl methane sulfonate (EMS) mutant library in the bread wheat variety Keda 527 (KD527) background. To reveal the genetic basis of lmpa1 mutant, phenotypic observations and analyses of chlorophyll content and photosynthesis were carried out in lmpa1, KD527 and their F1 and F2 derivatives. Further, bulked segregation analysis (BSA) in combination with a 660 K SNP array were conducted on the F2 segregation population of lmpa1/Chinese spring (CS) to locate the lmpa1 gene. Results Most agronomic traits of lmpa1 were similar to those of KD527 before lesion-like spots appeared. Genetic analysis indicated that the F1 plants from the crossing of lmpa1 and KD527 exhibited the lmpa phenotype and the F2 progenies showed a segregation of normal (wild type, WT) and lmpa, with the ratios of lmpa: WT = 124:36(χ2 = 1.008 < =3.841), indicating that lmpa is a dominant mutation. The combination of BSA and the SNP array analysis of CS, lmpa1 and lmpa1/CS F2 WT pool (50 plants) and lmpa pool (50 plants) showed that polymorphic SNPs were enriched on chromosome 5A, within a region of 30–40 Mb, indicating that the wheat premature aging gene Lmpa1 was probably located on the short arm of chromosome 5A. Conclusions EMS-mutagenized mutant lmpa1 deriving from elite wheat line KD527 conferred lmpa. Lmpa phenotype of lmpa1 mutant is controlled by a single dominant allele designated as Lmpa1, which affected wheat growth and development and reduced the thousand grain weight (tgw) of single plant in wheat. The gene Lmpa1 was tentatively located within the region of 30–40 Mb near to the short arm of chromosome 5A.

芒是许多禾本科作物穗部的重要结构,不仅可以作为区分不同品种以及基因定位的重要形态标记,而且在禾谷类作物的种子传播、籽粒灌浆、蒸腾作用及产量形成等方面起重要作用.该文综述了小麦(Triticum aestivum)、大麦(Hordeum vulgare)和水稻(Oryza sativa)芒的结构、功能与遗传调控机制研究进展,以期为芒性状遗传机理的进一步研究及其在育种中的应用提供参考.

为了明确本实验室创制的小麦新种质SN0594的光温反应特性及其利用价值,本研究以SN0594和不同春化习性的小麦品种为材料,在明确不同材料的春化基因和光周期基因组成特点的基础上,对其在不同环境条件进行生育期鉴定.结果表明,在Vrn-A1位点含有显性等位变异的多数小麦材料在人工气候室不经过低温春化且满足长日照的条件下都能够完成抽穗,其中小麦种质系SN0594在Vrn-A1位点含有显性等位变异基因Vrn-A1a,扬麦14和扬麦15含有显性等位变异基因Vrn-A1b,中国春等则含有显性等位变异基因Vrn-D1;不同环境鉴定结果表明,SN0594在人工气候室不经春化处理条件下,能够较早开花并完成生育周期,不同显性变异基因春性效应大小为Vrn-A1a>Vrn-A1b>Vrn-B1>Vrn-D1;田间鉴定结果表明,不同小麦材料在经过冬季低温春化后,其抽穗期与在人工气候室调查发生较大差异,其中SN0594和中国春抽穗较其他品种晚,证明除了春化基因以外,光周期Ppd-D1b等其他基因对小麦生育期影响也较大,需满足一定的长日照条件才能促使小麦抽穗开花.