发掘稳定的数量性状位点（Quantitative trait loci，QTL），并开发其紧密连锁分子标记，是进一步提高小麦产量的重要途径。本研究以中麦578/济麦22重组自交系（Recombinant inbreed lines，RIL）群体262个家系为材料，通过调查两年五个环境千粒重、粒长、粒宽、平均灌浆速率、穗粒数和株高共六个产量相关性状，利用50K SNP芯片基因型分析数据，构建了含有1501个bin标记的遗传连锁图谱，图谱总长度2384.95 cM。利用完备区间作图法，在1D（2）、2A（9）、2B（6）、2D、3A（2）、3B（2）、4A（5）、4D、5B（8）、5D（2）、7A（7）、7B（3）和7D（5）染色体上共定位到53个产量相关QTL，可解释表型变异的2.7–25.5%，其中23个QTL可在3个以上环境定位到，表现稳定；QKl.caas-2A.1、QKl.caas-7D、QKw.caas-7D、QGfr.caas-2B.1、QGfr.caas-4A、QGfr.caas-7A和QPh.caas-2A.1等7个QTL可能是新的位点。定位到的一因多效QTL共形成六个富集区段（R1–R6），分别包含2–6个QTL，位于2A、2B、4A、5B、7A和7D染色体；TaSus2-2B和WAPO-A1分别是位于2B和7A染色体上一因多效QTL的候选基因。7D染色体上的QTL富集区段内含有4个稳定QTL，分别控制千粒重、粒长、粒宽和株高，利用与其紧密连锁的侧翼标记，开发了KASP标记，在自然群体中对其效应进行了验证。本研究结果为小麦的高产育种和中麦578的进一步改良提供了基因和分子标记。

苗期根系的氮素吸收与利用效率是决定植株生长发育及产量收益的关键因素，研究氮肥调控下小麦苗期根系生物量及其相关形态学的遗传调控对培育高产稳产小麦品种具有重要意义。本研究利用扬麦16/中麦895构建的DH群体，分别在硝酸钙浓度为0 mmol L⁻¹（空白对照）、0.05 mmol L⁻¹（低氮）、2.0 mmol L⁻¹（高氮）3个梯度下进行液体培养，对4个根系生物量相关性状和5个根系结构性状进行基因定位，及连锁标记遗传转化研究。结果表明，不同氮肥处理与基因型间存在显著差异，根系生物量相关性状与结构性状间呈显著正相关，范围在0.20-0.98。基于全基因组660K SNP高密度遗传图谱，共定位到51个调控根系性状QTL，主要分布在12个根系性状调控基因富集区。并发掘出12个受氮肥调控影响的根系性状新基因，包括1AL染色体上携带受0氮调控的1个基因、1DS携带受高氮调控2个、4BL携带受高氮和低氮调控5个、7DS和7DL分别携带受低氮调控的3个和1个基因。4DS染色体上与Rht-D1 基因临近区域携带有控制根系性状且遗传表现稳定的基因QRRS.caas-4DS，解释表型变异为13.1%。12个根系性状基因富集区包括28个QTL位点，其中6BL和7BL染色体上的两个富集区C10和C11较为重要，主要控制根系干重、根表面积和幼苗干重等性状，连锁标记AX-109558906-6B和AX-95025477-7B已转化成育种可用的KASP标记。本研究发掘的QTL位点、QTL富集区及开发的KASP标记将有助于小麦育种工作中的苗期根系性状遗传改良。

Stripe rust is a serious foliar disease posing a grave threat to wheat production worldwide.  The most economical and environmentally friendly way to control this disease is to breed and deploy resistant cultivars.  Zhongmai 175 is an elite winter wheat cultivar conferring resistance to a broad spectrum of Puccinia striiformis f. sp. tritici (Pst) races.  To identify the resistance gene in the cultivar, genetic analysis was conducted using the parents, F₁, F₂ and F_2:3 populations derived from the cross of Lunxuan 987/Zhongmai 175.  Segregations in the F₂ and F_2:3 populations indicated a single dominant gene conferring resistance to stripe rust in Zhongmai 175, temporarily designated YrZM175.  Bulked segregant analysis (BSA) with wheat iSelect 90K SNP array determined a preliminary location of YrZM175.  Subsequently, YrZM175 was mapped on chromosome 2AS using simple sequence repeats (SSR), expressed sequence tags (EST) and newly-developed kompetitive allele specific PCR (KASP) markers, being flanked by Xgwm636 and Xwmc382 at genetic distances of 4.9 and 8.1 cM, respectively.  Comparison of reaction patterns of YrZM175 on 23 Pst races or isolates and pedigree analysis with other genes on chromosome 2AS suggested that it is likely to be a new gene for resistance to stripe rust.  The resistance gene and linked molecular markers will be useful in wheat breeding targeting for the improvement of stripe rust resistance.

    Starch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultivars, and to compare structure and functionality of starches in four leading cultivars Zhongmai 175, CA12092, Lunxuan 987, and Zhongyou 206. A wide variation in volume percentages of A- and B-type starch granules among genotypes was observed. Volume percentages of A- and B-type granules had ranges of 68.4–88.9% and 9.7–27.9% in the first cropping seasons, 74.1–90.1% and 7.2–25.3% in the second. Wheat cultivars with higher volume percentages of A- and B-type granules could serve as parents in breeding program for selecting high and low amylose wheat cultivars, respectively. In comparison with the B-type starch granules, the A-type granules starch showed difference in three aspects: (1) higher amount of ordered short-range structure and a lower relative crystallinity, (2) higher gelatinization onset (T_o) temperatures and enthalpies (ΔH), and lower gelatinization conclusion temperatures (T_c), (3) greater peak, though, and final viscosity, and lower breakdown viscosity and pasting temperature. It provides important information for breeders to develop potentially useful cultivars with particular functional properties of their starches suited to specific applications.

The Italian wheat cv. Strampelli displays high resistance to powdery mildew caused by Blumeria graminis f. sp. tritici. The objective of this study was to map quantitative trait loci (QTLs) for resistance to powdery mildew in a population of 249 F2:3 lines from Strampelli/Huixianhong. Adult plant powdery mildew tests were conducted over 2 yr in Beijing and 1 yr in Anyang and simple sequence repeat (SSR) markers were used for genotyping. QTLs Qpm.caas-3BS, Qpm.caas-5BL.1, and Qpm.caas-7DS were consistent across environments whereas, Qpm.caas-2BS.1 found in two environments, explained 0.4-1.6, 5.5-6.9, 27.1-34.5, and 1.0-3.5% of the phenotypic variation respectively. Qpm.caas-7DS corresponded to the genomic location of Pm38/Lr34/Yr18. Qpm.caas-4BL was identified in Anyang 2010 and Beijing 2011, accounting for 1.9-3.5% of phenotypic variation. Qpm.caas-2BS.1 and Qpm.caas-5BL.1 contributed by Strampelli and Qpm.caas-3BS by Huixianhong, seem to be new QTL for powdery mildew resistance. Qpm.caas-4BL, Qpm.caas-5BL.3, and Qpm.caas-7DS contributed by Strampelli appeared to be in the same genomic regions as those mapped previously for stripe rust resistance in the same population, indicating that these loci conferred resistance to both stripe rust and powdery mildew. Strampelli could be a valuable genetic resource for improving durable resistance to both powdery mildew and stripe rust in wheat.

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a devastating wheat disease worldwide. The Chinese wheat cultivar Chuanmai 32 has shown stable resistance to stripe rust for 10 yr in Sichuan Province, a hotspot for stripe rust epidemics. The objective of the present study was to map quantitative trait loci (QTL) for adult-plant resistance (APR) to stripe rust in a population of 140 recombinant inbred lines (RILs) derived from Chuanmai 32/Chuanyu 12. Field trials were conducted in Chengdu and Yaan, Sichuan, from 2005 to 2008, providing stripe rust reaction data for 6 environments. 797 simple sequence repeat (SSR) markers were screened for association with stripe rust reaction, initially through bulked segregant analysis (BSA). Based on the mean disease values averaged across environments, the broad-sense heritability of maximum disease severity (MDS) was 0.75. Two QTLs for stripe rust resistance were detected by composite interval mapping (CIM). They were designated QYr.caas-3BL and QYr.caas-3BS and explained from 6.6 to 20.1%, respectively, of the phenotypic variance across environments. QYr.caas-3BL came from Chuanmai 32; QYr.caas-3BS with lower effect was from the susceptible parent Chuanyu 12. Both QTLs appear to be new.

Dumpling is one of the most important traditional wheat products in China. Dumpling quality is determined by the characteristics of both flour and filling, thus improvement of flour quality plays an important role in improving dumpling quality. Thirty-nine Shandong winter wheat cultivars and advanced lines sown in Jinan, Shandong Province, China, in the 2008-2009 cropping season were used to determine genetic variation in Chinese raw dumpling quality and its relationship with flour characteristics. Large variations were observed for protein quality parameters in comparison with starch properties. Variation in color of the raw dumpling sheet was broader than that of sensory evaluation parameters of boiled dumpling among tested wheat cultivars, indicating the large influence of filling on dumpling color. Two cultivars, Jimai 20 and Zimai 12, were identified as possessing very good quality of raw dumpling, and 21 cultivars and advanced lines showed good quality. Protein and total starch content influenced the L* value of raw dumpling sheets. L* value at 0 and 2 h after sheeting were significantly influenced by protein content (r=-0.46 and -0.52, P<0.01) and total starch content (r=0.55 and 0.57, P<0.01), respectively. Flour yellow pigment was significantly corrected with a* (r=-0.67 and -0.62, P<0.01) and b* (r=0.87 and 0.84, P<0.01) value of raw dumpling sheets at 0 and 2 h after sheeting, respectively. Gluten strength parameters such as farinograph mixing tolerance index (MTI, r=-0.55, P<0.01) were positively associated with appearance. MTI and energy were also significantly and positively correlated with elasticity of raw dumpling, with r=-0.54 and 0.47 (P<0.01). The positive relationships between peak viscosity (r=0.51, P<0.01), breakdown (r=0.54, P<0.01), and smoothness of raw dumpling were also observed. Therefore, it is suggested that breeding programs should give more attention to gluten strength and starch pasting parameters for raw dumpling quality improvement.