荞麦是我国传统的药食两用作物,具有丰富的营养价值和独特的保健作用.近年来,荞麦在重庆地区广泛种植,但其与不同作物轮作的种植模式对荞麦生长和生物特性的影响鲜有报道.本试验以荞麦-大豆轮作(A1)、荞麦连作(A2)和荞麦-小麦轮作(A3)为主区处理,以酉荞 2 号(YQ2,B1)、乌克兰大粒荞(W,B2)、酉荞 1 号(YQ1,B3)和九江苦荞(J,B4)4 种不同荞麦品种为裂区处理,在重庆市北碚区进行了为期 3 年的定位试验,以研究不同种植模式对荞麦产量构成、植株形态和根系指标的影响,主要研究结果为:① 荞麦-大豆轮作下荞麦籽粒产量高于荞麦-小麦轮作处理,高于荞麦连作处理,且轮作使荞麦的单株粒数增加,单株粒重增大,千粒重也随之增加.② 同一生育时期,各荞麦品种在轮作模式下荞麦株高、地上部鲜质量和干质量获得最大值.相比于连作,轮作促进荞麦的增高、地上部鲜质量和干质量的增加.③ 荞麦轮作处理下的根系生物量的积累速率、根平均直径、总根长、总根体积、总根表面积和根尖数均高于连作处理,且在荞麦-大豆轮作下能获得最大值.综上,在本试验条件下,荞麦-大豆轮作模式有利于促进荞麦生长,提高荞麦产量,适合在重庆地区推广.

To explore the effect and application potential of different dwarf genotypes on wheat heterosis, the parents with different dwarf genes were used to configure hybrid combinations. The plant height, number of spikes per plant, 1 000-grain weight, and yield per plant of the parents and hybrid were measured at maturity stage. 10 traits were used to analyze the correlations between heterosis, plant heights of different dwarf genotype of hybrid combinations and investigated traits. The yield differences per plant among some genotypes in hybrid combinations of four different dwarf genotypes are significant. Rht1′+Rht21′, Rht1′+Rht2′ and Rht1″+Rht2′ genotypes had positive high heterobeltiosis on yield per plant. Rht1″+Rht21′ genotypes had distinct heterobeltiosis on number of spikes per plant, 1000-grain weight, biomass and yield per plant. Except for Rht1″+Rht21′ genotypes, other dwarf genotypes had hybrid combinations with heterobeltiosis of more than 10% in yield per plant. Rht1′+Rht2′ and Rht1″+Rht2′ dwarf genotypes had no significant correlation between plant height and yield per plant, but yield per plant was still significantly positively correlated with spike number per plant and biomass per plant. The four dwarf genotypes could reduce the plant height of hybrid wheat to different degrees and improve its lodging resistance. The hybrid with the Rht1′+Rht21′ genotype had the highest average heterobeltiosis, followed by the hybrid combination with the Rht1′+Rht2′ genotype. Therefore, it is easier to obtain theheterosis combinations by formulating the hybrid combination with those two genotypes in hybrid wheat breeding.

Common buckwheat (Fagopyrum esculentum M.) is an important pseudo-cereal crop and contains an abundance of nutrients and bioactive compounds. However, the yield of buckwheat is low compared to that of other major crops. QTL mapping and candidate gene screening of grain size are very important for increasing production in common buckwheat through molecular breeding in the future. In the present study, an F1 segregating population with 217 individuals was established using a cross between Ukraine daliqiao (UD) and Youqiao 2 (YQ2) that showed a significant difference in grain size. The InDel and SSR primers were developed based on transcriptome sequencing between parents in the previous study. We constructed a genetic linkage map, including 39 SSR loci and 93 InDel loci, with a total length of 1398.33 cM and an average spacing of 10.59 cM. Combined with the grain size phenotype data of the F1 population, a total of 14 QTL were detected, including 6-grain length QTL, 3-grain width QTL, and 5 hundred-grain-weight QTL. QTL of grain width and hundred-grain weight were all detected near SWU_Fe_InDel086 and SWU_Fe_InDel076. Some putative candidate genes with the ex1pression or InDel difference between parents were screened within the QTL interval. This study would lay the foundation for map-based cloning and molecular mechanism of grain size and ultimately improvement of yield in common buckwheat.

Common buckwheat (Fagopyrum esculentum M.) is known for its adaptability, good nutrition, and medicinal and health care value. However, genetic studies of buckwheat have been hindered by limited genomic resources and genetic markers. In this study, Illumina HiSeq 4000 high-throughput sequencing technology was used to sequence the transcriptome of green-flower common buckwheat (Gr) with coarse pedicels and white-flower Ukrainian daliqiao (UD) with fine pedicels. A total of 118,448 unigenes were obtained, with an average length of 1248 bp and an N50 of 1850 bp. A total of 39,432 differentially expressed genes (DEGs) were identified, and the DEGs of the porphyrins and chlorophyll metabolic pathway had significantly upregulated expression in Gr. Then, a total of 17,579 sequences containing SSR loci were detected, and 20,756 EST-SSR loci were found. The distribution frequency of EST-SSR in the transcriptome was 17.52%, and the average distribution density was 8.21 kb. A total of 224 pairs of primers were randomly selected for synthesis; 35 varieties of common buckwheat and 13 varieties of Tartary buckwheat were verified through these primers. The clustering results well verified the previous conclusion that common buckwheat and Tartary buckwheat had a distant genetic relationship. The EST-SSR markers identified and developed in this study will be helpful to enrich the transcriptome information and marker-assisted selection breeding of buckwheat.

西南11号是利用蓝粒标记小麦隐性核型不育系12L8016与恢复系川14品16配制的杂交组合,2年区域试验每hm2平均产量3664.54kg,比对照渝麦13增产9.43％;生产试验平均产量3717.12kg,比对照渝麦13增产7.27％;异地制种最高产量达到8173.5kg,克服了杂交小麦制种产量低的缺点.2021年通过重庆市农作物品种审定委员会审定,审定编号:渝审麦20210001,定名为西南11号,适宜于重庆地区种植.

[目的]通过分析不同杂交小麦组合及其亲本苗期叶片的光合特性与籽粒产量的相关性,为杂交小麦强优势组合早期筛选和预测提供理论依据.[方法]以2个恢复系和4个不育系及其配制的6个杂交小麦组合为材料,在大田种植条件下测定小麦苗期叶片的光合特性,包括净光合速率(Pn)、气孔导度(Gx)、胞间CO2浓度(C1)、蒸腾速率(Tr)、水分利用效率(WUE)、叶绿素含量、Rubisco活性及其大小亚基编码基因rbcL、rbcS相对表达量;调查成熟期的产量性状,包括株高、主穗穗长、单株地上生物量、有效穗数、穗粒数、单株籽粒产量、主穗小穗数、千粒重、收获指数,并分析杂种优势以及光合性状与产量性状的相关性.[结果]杂交小麦苗期的净光合速率、气孔导度、蒸腾速率均表现出显著的超高亲优势,其中净光合速率的平均超高亲优势为15.4％,气孔导度为21.3％,蒸腾速率则为11.46％,净光合速率值高的恢复系所配制的杂交组合具有更高的净光合速率和杂种优势,而胞间二氧化碳浓度、水分利用效率则少数有负向优势.成熟期有效穗数、单株籽粒产量及单株生物量具有较高的超高亲优势,其中穗数的超高亲优势值达到最高,平均优势值为34.21％.相关性分析表明,净光合速率与气孔导度、蒸腾速率、单株生物量和单株籽粒产量呈显著或极显著正相关,说明气孔导度、蒸腾速率可辅助筛选高光合小麦,同时苗期净光合速率与产量关系密切.叶绿素含量、Rubisco活性、大小亚基编码基因rbcL、rbcS相对表达量的杂种优势差异较大,其中杂交小麦Rubisco活性均高于双亲,且具有显著的超高亲优势,平均超高亲优势为5.38％.编码基因中,与rbcL相比rbcS具有更高的超高亲优势和中亲优势,而叶绿素含量主要表现为负向优势,少数表现出中亲优势,极少数表现出超高亲优势,且各项指标与净光合速率均无显著相关性.[结论]杂交小麦在苗期已表现出显著的杂种优势,尤其是净光合速率、气孔导度和蒸腾速率,而净光合速率与单株产量、单株生物量显著正相关,因此结合小麦杂交组合的田间表现,苗期净光合速率高低可以作为早期预测杂交组合的产量潜力的参考依据.

为探明小型机械在丘陵山区播种苦荞的农机农技配套技术,以酉荞5号(中抗倒伏苦荞品种)为试验材料,于2016和2017年秋季,利用播种深度2(A1)、3(A2)和4 cm(A3),播种量16.8(B1)、33.6(B2)和50.4 kg·hm-2(B3),施肥量150(C1)、300(C2)和450 kg·hm-2(C3)三因素三水平设计L934正交试验,研究9个处理水平对苦荞倒伏和产量的影响.结果表明:对苦荞倒伏影响表现为播种深度>播种量>施肥量,随播种深度的增加,倒伏时期后移,3 cm播种深度苦荞倒伏级别和倒伏率最小;随播种量、施肥量的增加倒伏级别和倒伏率都增大.茎秆基部第二节间长度、茎粗、鲜重和抗折力从盛花期到成熟期逐渐增加,对茎秆基部第二节间茎粗、鲜重和抗折力的影响表现为播种量>播种深度>施肥量,随播种量的增加,第二节间茎粗、鲜重和抗折力逐渐减小,第二节间长度先减后增;播深对茎秆第二节间长度影响大于播量和施肥量,随播深的增加,第二节间茎粗、鲜重和抗折力先增后减,第二节间长度先减后增;随施肥量的增加,第二节间长度、直径、鲜重和抗折力逐渐增加.从盛花期到成熟期茎秆基部第二节间4-香豆酸辅酶A连接酶(4-coumarate:CoA ligase,4CL)、苯丙氨酸解氨酶(phenylalanine ammonia-lyase,PAL)、肉桂醇脱氢酶(cinnamyl alcohol dehydrogenase,CAD)活性先升后降,木质素含量逐渐增加,对木质素含量、4CL、PAL、CAD酶活性的影响表现为播种量>播种深度>施肥量.对产量、单株粒数和总株数的影响表现为播种量>播种深度>施肥量,对千粒重的影响表现为播种量>施肥量>播种深度.随播种量的增加,总株数增加,单株粒数和千粒重减少,产量先增后减;随播种深度的增加,产量、单株粒数和总株数先升后降,千粒重先减后增;随施肥量的增加,总株数和产量差异不显著,单株粒数和千粒重显著增加.本试验条件下,丘陵山区苦荞小型机械播种A2B2C3处理(3 cm播种深度、33.6 kg·hm-2播种量和450 kg·hm-2施肥量)最佳.

[目的]通过亲本条锈病的抗性评价预测F1代杂交种的抗病性,增强杂交小麦抗病育种的可预见性.[方法]以CYR23、CYR31、CYR33、CYR344个小麦条锈菌(Puccinia striiformis f.sp.tritici)生理小种作为供试菌源,感病小麦品种铭贤169作为阴性对照,通过成株期混合接种,对13份恢复系(父本)材料和21份不育系(母本)材料及其F1代杂交种进行抗病性鉴定,并利用Yr5、Yr9、Yr10、Yr15、Yr17、Yr18、Yr26等抗条锈基因的分子标记或基因标记对其可能携带的抗条锈基因进行分子检测.同时通过半定量PCR方法在亲本及部分F1代植株的成株期进行条锈菌侵染量测定.[结果]所有材料均未鉴定到Yr5、Yr10、Yr15,Yr26多存在于四川品系,Yr9、Yr17多存在于北方品系,本研究所有恢复系材料均未鉴定到Yr18.亲本抗条锈基因在F1代杂交种得到了聚合,符合遗传规律,表明分子标记可以用于杂交小麦抗病辅助选育.来自四川的恢复系及其F1代杂交种整体表现优良抗性,推测其具有纯合显性的抗条锈基因,同时,这些小麦材料可以用于我国小麦抗条锈育种.F1代的实际鉴定反应型趋于亲本反应型的平均值,二元回归分析结果表明亲本和F1代的反应型之间有显著相关性(R2=0.812).来自四川的恢复系及其F1代对新毒性小种CYR34表现优良抗性,但亲本中未检测到Yr5、Yr15,推测其可能含有未知的抗条锈病基因.利用半定量PCR方法对所有恢复系、不育系和部分F1代杂交种分别进行了供试条锈菌生理小种的菌量测定,结果显示所有亲本及其杂种中均未检测到CYR23,恢复系15CA50、不育系17L6078和15L7128有少量CYR31侵染,恢复系川13品6、MR1101和川麦98及其F1代杂交种未检测到CYR33、CYR34.同时发现,对不同生理小种抗性互补的亲本能有效提高F1代的抗病性.[结论]根据双亲对条锈病的反应型可以预测其F1代杂交种的抗性水平,双亲的抗病水平越高,其F1代杂交种的抗性就越好.同时可以选用具有不同条锈病生理小种抗性互补的亲本来提高F1代杂交种的抗性水平.研究结果有助于探究亲本与F1代杂交种之间的抗病规律,同时为杂交小麦抗病育种提供可参考的实践方案.

A large set of potential microsatellites markers covering the entire genome are required for genetic diversity, mapping and functional genomics studies. In this study, a total of 37,572 microsatellites with frequency of 83.25 microsatellites per Mb were mined in the recently sequenced Fagopyrum tataricum. Among these 37,572 microsatellites, most of the microsatellites were di-nucleotide (26,196, 69.72%) and AT/TA repeat motifs were the most abundant (24,742, 65.85%). A total of 26,549 microsatellite markers were designed from the flanking sequences of 37,572 microsatellites and 2643 (9.96%) were genic microsatellite markers. All of these newly-developed microsatellite markers were physically anchored to the eight chromosomes of F. tataricum and the first and high-density physical map was constructed with an average marker density of 58.82 markers per Mb. Amplification efficiency and experimental evaluation of the newly-developed microsatellite markers assessed with 440 markers randomly selected in F. tataricum, showed that these microsatellite markers are highly effective and valuable. The large number of new microsatellite markers and their location on the physical map provided a valuable resource for studying diversity, constructing genetic maps, functional gene mapping, QTL exploration and molecular breeding in Fagopyrum species.

Common buckwheat (Fagopyrum esculentum M.) belongs to the eudicot family Polygonaceae, Fagopyrum Mill, and its seeds have high nutritional value. The mechanism of seed development of common buckwheat remains unclear at the molecular level and no genes related to seed size have been identified. In this study, we performed genome-wide transcriptome sequencing and analysis using common buckwheat seeds at 5 days post anthesis (DPA) and 10 DPA from two cultivars (large-seeded and small-seeded). A total of 259,895 transcripts were assembled, resulting in 187,034 unigenes with average length of 1097 bp and N50 of 1538 bp. Based on gene expression profiles, 9127 differentially expressed genes (DEGs) were identified and analyzed in GO enrichment and KEGG analysis. In addition, genes related to seed size in the IKU pathway, ubiquitin-proteasome pathway, MAPK signaling pathway, TFs and phytohormones were identified and analyzed. AP2 and bZIP transcription factors, BR-signal and ABA were considered to be important regulators of seed size. This study provides a valuable genetic resource for future identification and functional analysis of candidate genes regulating seed size in common buckwheat and will be useful for improving seed yield in common buckwheat through molecular breeding in the future.

Nitrogen fertilizer and planting density are two crucial factors that affect the yield of common buckwheat (Fagopynun esculentum M.). Yougiao2, a common buckwheat cultivar with high photosynthetic capacity and planted widely in local production was used to investigate the effects of nitrogen fertilizer and planting density on the leaf photosynthetic characteristics, agronomic traits, and grain yield in common buckwheat by a split plot design. The main plots were assigned to three nitrogen fertilizer rates: 0, 45, and 90 kg ha(-1), and the subplots were assigned to three planting densities: 60, 90, and 120 plants m(-2). Results showed that the grain yield was significantly and positively correlated with net photosynthesis rate (P-n), stomatal conductance (G(s)), transpiration rate (T-r), stomatal limitation value (L-s), chlorophyll content (SPAD value), leaf area index (LAI), plant height, stem diameter, branch number, internode number, grain number per plant, and 1000-grain weight, while significantly and negatively correlated with intercellular CO2 concentration (C-i) and water-use efficiency (WUE). The P-n, G(s), T-r, L-s, SPAD, LAI, grain yield, stem diameter, branch number, internode number, grain number per plant, and 1000-grain weight increased and then decreased with the increase of nitrogen fertilizer and planting density, and their maximum values appeared in the nitrogen fertilization of 45 kg ha(-1) and planting density of 90 plants m(-2) treatment. The C-i and WUE decreased and then increased with the increase of nitrogen fertilizer and planting density, and their minimum values appeared in the nitrogen fertilization of 45 kg ha(-1) and planting density of 90 plants m(-2) treatment. The plant height increased with the increase of nitrogen fertilizer, while decreased with the increase of planting density. These results suggested that nitrogen fertilizer and planting density had significant effects on the leaf photosynthetic capacity, agronomic traits, and grain yield of common buckwheat, and the combination of nitrogen fertilization of 45 kg ha(-1) and planting density of 90 plants m(-2) is recommended for common buckwheat planting.

Lignin plays an important role in increasing the mechanical intensity of culm and improving lodging resistance of culm. In this study, three common buckwheat, Youqiao2 (lodging-tolerant cultivar; YQ2), Ningqiao1 (middle lodging-tolerant cultivar; NQ1) and Ukraine daliqiao (lodging-susceptible cultivar; UD), were used to investigate the effects of spraying exogenous hormones uniconazole (S-3307) or gibberellic acid (GA3) on lignin metabolism and its relation to lodging resistance in the three common buckwheat cultivars. Results showed that application of S-3307 significantly increased lignin content and its related enzymes activities of phenylalanine ammonia-lyase (PAL), 4-hydroxy cinnamoyl CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POD). The major genes involved in lignin synthesis, PAL, CCR (cinnamyl CoA reductase), C4H (cinnamate4-hydroxylase), 4CL and CCoAOMT (caffeoyl CoA O-methyltransferase), were all upregulated expression, and COMT (catechol-O-methyltransferase) was downregulated. What is more, application of S-3307 significantly improved the resistance of common buckwheat stem to lodging and increased yield. Whereas, spraying with GA3 caused opposite effect on those characteristics. These results suggested that application of exogenous S-3307 or GA3 significantly changed the risk of lodging occurred by regulating the lignin metabolism in culms of common buckwheat.

Waxy wheat (Triticum aestivum L.) is grown throughout the world for its specific quality. Fertilization and planting density are two crucial factors that affect waxy wheat yield and photosynthetic capacity. The objectives of the research were to determine the effects of fertilization and planting density on photosynthetic characteristics, yield, and yield components of waxy wheat, including Yield, SSR, TGW, GNPP, GWPP, PH, HI, Pn, Gs, Ci, E and WUE using the method of field experiment, in which there were three levels (150, 300, and 450 kg ha–1) of fertilizer application rate and three levels (1.35, 1.8, and 2.25 × 106 plants ha–1) of planting density. The results suggested that photosynthetic characteristics, yield, and yield components had close relationship with fertilization levels and planting density. Under the same plant density, with the increase of fertilization, Yield, SSR, TGW, GNPP, GWPP, HI, Pn, Gs, E and WUE increased and then decreased, PH increased, but Ci decreased. Under the same fertilization, with the increase of plant density, Yield, SSR, TGW, GNPP, GWPP, HI increased and then decreased, PH, Pn, Gs and E increased, PH and WUE declined. The results also showed that F2 (300 kg ha–1) and D2 (1.8 × 106 plants ha–1) was a better match in this experiment, which could obtain a higher grain yield 4961.61 kg ha–1. Consequently, this combination of fertilizer application rate and plant densities are useful to get high yield of waxy wheat.

甜养极易倒伏,而株高和茎粗是影响甜荞倒伏的重要性状.以高秆健壮品种酉荞2号和矮秆纤细品种乌克兰大粒荞为亲本配制正、反交组合,P1、P2、F1、B1、B2和F2群体株高和茎粗的遗传分析表明,株高和茎粗的最适遗传模型均为2对加性-显性-上位性主基因+加性-显性多基因模型.株高正交组合中2对主基因加性效应均为-1.39,显性效应分别为-6.59和-7.91,B1、B2和F2群体主基因遗传率分别是45.73％、63.49％和81.12％,多基因遗传率分别是27.41％、0.95％和0;反交组合中2对主基因加性效应值均为-1.63,显性效应分别为-7.03和-4.19,B1、B2和F2群体中主基因遗传率是41.51％、66.18％和81.81％,多基因遗传率分别是11.19％、0和0.茎粗正交组合中2对主基因加性效应均为0.03,显性效应分别为-0.50和-0.08,B1、B2和F2群体中主基因遗传率分别是37.26％、48.80％和72.10％,多基因遗传率分别是11.18％、0和0;反交组合中2对主基因加性效应均为-0.15,显性效应分别为-0.30和-0.16,B1、B2和F2群体中主基因遗传率是76.22％、47.12％和82.51％,多基因遗传率分别为0、14.53％和0.可见,株高的主基因+多基因遗传率在80％以上,可在低世代进行选择;茎粗的主基因+多基因遗传率在80％以下,采取合理的栽培措施可以提高养麦抗倒伏能力.

[目的]通过研究硅肥对甜荞倒伏和产量相关性状的影响,筛选甜荞栽培最适施硅量,为其实现高产、稳产、抗倒伏提供参考.[方法]以宁荞1号(中抗倒伏)为试验材料,2015-2016年在西南大学歇马科研基地进行田间试验,试验设置基施0 (CK)、100 kg·hm-2(S1)、200 kg·hm-2(S2)、300 kg·hm-2(S3)和400 kg·hm-2(S4)5种施硅量梯度(SiO2≥25％),研究各生育阶段不同器官硅含量及倒伏和产量相关指标.[结果](1)根中硅含量高于茎,从盛花期到成熟期先增后减,在灌浆期达到最大值,并且随着施硅量的增加而增加;茎中硅含量从盛花期到成熟期逐渐增加,随着施硅量增加先增后减.(2)总根长、总根表面积、平均根直径和根尖数从盛花期到成熟期逐渐增加;根表面积随施硅量的增加而增加;平均根直径和根尖数随着施硅量增加先增加后减少,S2处理达到最大值.(3)茎秆基部第二节间长度、直径、鲜重和抗折力从盛花期到成熟期逐渐增加;茎秆基部第二节间长度、直径随施硅量的增加而增加;茎秆基部第二节间鲜重和抗折力随着施硅量的增加先增加后减少,均在S3处理达到最大值.(4)木质素含量从盛花期到成熟期逐渐增加,4CL、PAL和CAD活性从盛花期到成熟期先升后降,在灌浆期达到最大值;木质素含量,4CL、PAL和CAD活性随着施硅量的增加先升后降,在S3处理达到最大值.(5)硅肥降低甜荞倒伏级别,显著减小倒伏率;当施硅量在300-400 kg·hm-2时,甜荞倒伏时期推迟到成熟期.(6)产量、单株粒重和千粒重随着硅肥施用量的增加先增后减;单株粒数随着硅肥施用量的增加而增加.[结论]本试验条件下,硅肥基施300 kg·hm-2效果最佳,可在实际生产中推广应用.

In order to screen suitable high hybrid wheat seed production technology, the split-plot experiment design was adopted and study was carried out about the effects of the different row ratios of male and female parents and application amount of nitrogen fertilizer on hybrid wheat seed production and its component factors. The results showed that the seed production increased with the increase in the number of female parent row. When the row ratio of male and female parents was 2:6, the seed production was 3 683.8 kg/ha; when the application amount of nitrogen fertilization was 50 kg/ha, the seed production was 3 649.4 kg/ha; the interaction between the row ratio of male and female parents and the application amount of nitrogen fertilizer indicated that when the row ratio of male and female parents was 2:6 and the application amount of nitrogen fertilizer was 300 kg/ha, the seed production reached the highest (4 160.6 kg/ha). The row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the component factors of seed production, including the number of grains per spike, spike weight and setting percentage. When the row ratio of male and female parents was 2:5, the number of grains per spike, spike weight and setting percentage were the highest at 26.7 grains, 1.12 g, and 62.6% respectively; when application amount of nitrogen fertilizer was 450 kg/ha, the number of grains per spike, spike weight and setting percentage were the highest at 26.0 grains, 1.08 g, and 59.2% respectively; the interaction of row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the number of grains per spike, spike weight and setting percentage; when the row ratio of male and female parents was 2:5 and the application amount of nitrogen fertilizer was 300 kg/ha, the number of grains per spike, spike weight and setting percentage were the highest at 29.6 grains, 1.24 g, and 71.6% respectively. Conclusions: the number of grains per spike is the largest component factor for seed production. Increasing the number of grains per spike can increase the seed production. According to the effects of row ratio of male and female parents and application amount of nitrogen fertilizer on the component factors of seed production, the optimal condition was 2:5-2:6 for row ratio of male and female parents and 300-450 kg/ha for application amount of nitrogen fertilizer.

[Objective] This research aims to study the content change rule oflignin,total lignin monomer,G,S and H type lignin monomer of culm with different lodging resistance capabilities of buckwheat cultivars at different stages,so as to determine the lignin and lignin monomer synthetic characteristics.[Method] The varieties of Youqiao2 (YQ2,high lodging resistance),Xinnong1 (XN1,medium lodging resistance) and Ukraine Daliqiao (UD,sensitive to lodging) were used as test materials.The field experiment arranged in a factorial randomized complete design,with three replicates.Acetyl bromide method was used to determine the lignin content of different lodging resistance varieties at different growth stages.GC-MS method was conducted to determine the content of total lignin monomer which includes G,S and H type lignin monomer.Stems in common buckwheat were used to determine stem bending force and lodging index.[Result] At same growth stages,YQ2 was superior in culm breaking resistance and lodging index compared with XN1 and UD.The culm breaking resistance increased firstly and then decreased from the stage of branching to milk ripe,the maximum values arrived at full bloom stage.The lodging index among different varieties changed differently,the lodging index of YQ2 and UD increased and then decreased from branching to milk ripe stage,and the maximum values arrived at full bloom stage.The lodging index of XN1 increased gradually from branching to milk ripe stage,and the maximum values arrived at milk ripe stage.The content of culm lignin and lignin monomer increased from branching to milk ripe stage.The YQ2 contained higher lignin and lignin monomer than XN1 and UD.At the same growth stage,the content of S type monomer was higher than G type monomer,and the H type monomer was the lowest.From branching to milk ripe stage,S and G type monomer increased gradually,but H type monomer decreased gradually.Furthermore,from branching to milk ripe stage,the ratio of S/G decreased,and the ratio of G type monomer to total lignin monomer increased gradually.[Conclusion] The main type of lignin monomer of culm in common buckwheat is S-G type.At different growth stages,the content of lignin,total lignin monomer,G,S and H type lignin monomer of high resistance varieties are higher than moderate resistance and lodging susceptible varieties.The S type lignin monomer increased quickly at branching stage,and G type lignin monomer increased in a great deal from branching to maturity stage.

In order to screen suitable high hybrid wheat seed production technology, the split-plot experiment design was adopted and study was carried out about the effects of the different row ratios of male and female parents and application amount of nitrogen fertilizer on hybrid wheat seed production and its component factors. The results showed that the seed production increased with the increase in the number of female parent row. When the row ratio of male and female parents was 2:6, the seed production was 3 683.8 kg/ha; when the application amount of nitrogen fertilization was 50 kg/ha, the seed production was 3 649.4 kg/ha; the interaction between the row ratio of male and female parents and the application amount of nitrogen fertilizer indicated that when the row ratio of male and female parents was 2:6 and the application amount of nitrogen fertilizer was 300 kg/ha, the seed production reached the highest (4 160.6 kg/ha). The row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the component factors of seed production, including the number of grains per spike, spike weight and setting percentage. When the row ratio of male and female parents was 2:5, the number of grains per spike, spike weight and setting percentage were the highest at 26.7 grains, 1.12 g, and 62.6% respectively; when application amount of nitrogen fertilizer was 450 kg/ha, the number of grains per spike, spike weight and setting percentage were the highest at 26.0 grains, 1.08 g, and 59.2% respectively; the interaction of row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the number of grains per spike, spike weight and setting percentage; when the row ratio of male and female parents was 2:5 and the application amount of nitrogen fertilizer was 300 kg/ha, the number of grains per spike, spike weight and setting percentage were the highest at 29.6 grains, 1.24 g, and 71.6% respectively. Conclusions: the number of grains per spike is the largest component factor for seed production. Increasing the number of grains per spike can increase the seed production. According to the effects of row ratio of male and female parents and application amount of nitrogen fertilizer on the component factors of seed production, the optimal condition was 2:5-2:6 for row ratio of male and female parents and 300-450 kg/ha for application amount of nitrogen fertilizer.

Lignin is closely related to the lodging resistance of common buckwheat (Fagopyrum esculentum Moench.). However, the characteristics of lignin synthesis related genes have not yet been reported. We investigated the lignin biosynthesis gene expression, activities of related enzymes, and accumulation of lignin monomers during branching stage, bloom stage, and milky ripe stage by real-time quantitative PCR, UVspectrophotometry, and gas chromatography-mass spectrometry in the 2nd internode of three common buckwheat cultivars with different lodging resistance. The results showed that lignin content and the activity of phenylalanine ammonia lyase (PAL), 4-coumarate: CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POD) were closely related to the lodging resistance of common buckwheat. Further, we studied gene expression of cinnamate 4-hydroxylase (C4H), caffeoyl-CoA O-methyltransferase (CCoAOMT), ferulate 5-hydroxylase (F5H), cinnamoyl-CoA reductase (CCR), and caffeic acid O-methyltransferase (COMT). The lignin biosynthesis genes were divided into three classes according to their expression pattern: 1) expression firstly increasing and then descending (PAL, 4CL, CAD, C4H, CCoAOMT, F5H, and CCR), 2) expression remaining constant during maturation (C3H), and 3) expression decreasing with maturation (COMT). The present study provides preliminary insights into the expression of lignin biosynthesis genes in common buckwheat, laying a foundation for further understanding the lignin biosynthesis.

Nearly 100,000 ha in the Three Gorges Reservoir Area (TGRA) are in wheat production and the area is a junction where wheat stripe rust overwinters and causes epidemics the next spring; thus the area plays a pivotal role in wheat stripe rust epidemics in China. To better understand wheat resistance levels and the application of Yr genes in this area, 116 wheat cultivars (lines) were collected from the TGRA to investigate stripe rust resistance during the 2014–2016 cropping seasons. Seedling resistance evaluation results indicated that only nine accessions (7.8%) were immune or nearly immune to three predominant races of CYR32, CYR33 and PST-V26. In the field evaluation, 51 accessions (43.9%) showed adult-plant resistance, whereas 56 accessions (48.3%) were susceptible. The application of resistant sources focused on ineffective Yr9 (26.7%) and Yr17 (18.9%), and gradual ineffective Yr26 (34.5%), while effective Yr5, Yr10 and Yr15 were absent. Among them, 21 accessions (18.1%) were combined with two resistance genes. Both low resistance and more concentrated use of Yr genes indicated that this region faces a major risk for a wheat stripe rust epidemic. To improve the wheat resistance level in the TGRA, it is important to discover new all-stage resistance resources and diversify resistance resources for breeding.