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1.
Spot blotch (SB), caused by Bipolaris sorokiniana, is a devastating disease of wheat globally, especially in South Asia and South America. Understanding the genetics of resistance to SB is important for developing breeding strategies to improve resistance. A panel of 301 genotypes from Afghanistan was phenotyped over two crop seasons using a mixture of virulent B. sorokiniana isolates and genotyped using DArTSeq to obtain genome-wide markers. Fifty genotypes (16.6%) showed disease scores less than the resistant control. Principal component analysis using the genotypic data clustered the genotypes into five different groups. Among models used for genome-wide association mapping, the multilocus mixed model, and fixed and random model circulating probability unification algorithms were most effective in identifying significant marker-trait associations (MTA). Twenty-five MTAs at p ≤ .001 were identified on chromosomes 1A, 1B, 1D, 2B, 2D, 3A, 3B, 4A, 5A, 5B, 6A, 7A, and 7D, indicating the quantitative nature of resistance to SB. Phenotypic variation explained by these markers ranged from 2.0% to 17.7%, and genomic regions on the chromosomes 1D, 2D, 3A, 3B, 4A, 5A, and 5B coincided with loci identified in previous studies. Three single nucleotide polymorphism (SNP) markers on chromosomes 1B (SNP 1113207) and 5A (SNPs 5411867 and 998276) were significant in both crop seasons as well as in the combined analysis across seasons. Marker 5411867 is close to Vrn-A1, shown to be associated with SB in previous studies. Furthermore, among known SB resistance genes, Sb2 on chromosome 5B was predicted to be significant in this panel.  相似文献   
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Crop production in arid/semi-arid regions is restricted by soil moisture and nitrogen (N) deficiencies. Consequently, sufficient levels of N and irrigation are important in improving the crop's productivity. Therefore, a 2-year field experiment was conducted to understand influences of watering techniques namely 300, 500 and 700 mm with contrasting N supply (0, 60, 120 and 180 kg ha?1) on wheat cv. “landrace” productivity, dry matter translocation (DMT) and contribution of pre-anthesis assimilates to the grain (CPAAG, %). Experiments were conducted each year using a split-plot design with three replications at a private farm, North Hamedan Province, Iran. Accordingly, when 500/700 mm water was applied, CPAAG values were higher than those obtained after applying 300 mm water, i.e. 49.99 and 45.45 vs. 40.13%. The highest productivity in terms of grain yield, grain N concentration, nitrogen harvest index, special products analysis division and protein content was achieved in normal deficiencies of irrigation and N. This was further supported by a higher leaf area index, crop growth rate and N uptake of such treatment. Meanwhile, co-application of 120 kg N and 500 mm water significantly improved DMT, water and N use efficiency, and it was the optimal scheme for wheat production.  相似文献   
4.
【目的】了解我国西南地区不同玉米地方品种的遗传多样性,为合理利用这些玉米种质资源提供参考。【方法】以西南地区12份玉米地方品种为材料,对Glb1基因片段进行克隆、测序及序列比对,分析其遗传多样性。【结果】12份玉米材料Glb1基因序列长度为1138-1149 bp,其序列一致性为96.21%。12份材料Glb1基因序列间存在较多的变异位点,大于等于3 bp的插入/缺失有8个,主要位于第81-84、122-128、161-164、368-371、428-442、668-680、966-976和1003-1011 bp。不同玉米地方品种材料间的遗传相似系数为96.50%-100.00%,平均为98.58%。根据聚类分析结果可将12份材料分为五大类,且来源于同一地区的玉米材料趋向于聚为一类。【结论】Glb1基因具有较高的保守性,所选材料间Glb1基因序列存在一定的遗传多样性,利用Glb1基因序列可作为鉴定不同玉米地方品种的一种理想分子标记。  相似文献   
5.
Mexican pigmented maize (Zea mays L.) landrace kernels have been scantily evaluated regarding potential as functional food. In this study, eight Mexican pigmented (yellow and red) maize accessions of Tuxpeño, Tabloncillo and Chapalote landraces collected in the northwestern region of Mexico were processed into tortilla to determinate carotenoid profiles, as well as their Oxygen Radical Absorbance Capacity for Lipophilic extract (ORAC-L). The total carotenoid content ranged from 3.66 to 5.56 mg LE/kg DW in the yellow maize and from 1.49 to 3.49 mg LE/kg DW in the red maize among all raw genotypes. Lutein and zeaxanthin were major carotenoids in all pigmented maize, accounting for ∼85% of total carotenoids. The traditional nixtamalization and lime-cooking extrusion process significantly (p < 0.05) decrease total carotenoid and ORAC-L assays when compared to raw kernels. Traditional tortillas retained among 72.0–87.6% and 65.1–78.8% of total carotenoids and ORAC-L levels respectively, compared to 68.8–79.5% and 60.3–75.5% assayed in extruded tortillas. Interestingly, traditional and extruded tortillas maintained more 72.7 and 60%, respectively; of the lutein concentration associated with raw grains. Our results suggest that yellow maize landrace could be considered for the elaboration of nixtamalized food products with nutraceutical potential.  相似文献   
6.
河南省玉米地方品种主要产量性状间的相关和通径分析   总被引:2,自引:1,他引:1  
为了更有效的改良和利用现有的玉米地方品种,基于表型和基因型的聚类分析的基础上,从不同类群中筛选到46份河南省优异地方品种,进行产量及其相关性状的重复鉴定。相关和通径分析结果表明,对产量影响最大的是千粒重(r=0.7734),其次为穗长和穗粗,均达极显著正相关,其中千粒重具有最大的正向直接通径系数(P=0.6518),而穗行数对产量影响较小,未达显著水平。因此,提高千粒重,同时兼顾其它产量性状是提高河南地方品种产量的有效途径。结合田间株型等性状,从众多的地方品种中培育产量突出的自交系,为玉米育种积累材料,并为今后的相关研究提供参考。  相似文献   
7.
[目的]对3份小麦农家品种‘矮秆芒麦’、‘红头麦’和‘大红头’进行苗期抗性的遗传分析,研究它们的抗白粉病遗传特点,为其在抗病育种中的有效利用提供依据.[方法]将这3份小麦农家品种分别与感病品种‘铭贤169’正、反杂交,获得了F1和F2代.利用白粉菌E09菌株,分别对这3份农家品种、感病亲本‘铭贤169’以及各自的F1和F2代植株进行抗性鉴定.调查统计的数据经卡方测验分析其符合度.[结果]这3份农家品种对白粉菌E09菌株的抗性均由1对隐性核基因控制.[结论]3份农家品种对石家庄本地区的混合白粉病菌表现出良好的抗性,并且对E09的抗性均由1对隐性基因控制.可以进一步对它们进行分子标记及定位研究,为其作为抗源在小麦抗白粉病育种中的应用奠定基础.  相似文献   
8.
A total of 415 sorghum (Sorghum bicolor (L.) Moench) accessions representing different regions of Ethiopia, Eritrea and a group of introduced lines were evaluated for 15 quantitative characters to determine the extent and geographical pattern of morphological variation. The extent of variation was highly pronounced for agronomically important characters for sorghum. These characters included plant height, days for 50% flowering, peduncle exsertion, panicle length and width, number and length of primary branches per panicle and thousand seed weight. Significant regional variation was also observed for most of the characters. The results implied that environmental factors such as altitude, rainfall, temperature and growing period are important in regional variation. Mean for plant height and for days for 50% flowering showed clinal variation along the gradients of rainfall pattern and growing period in Ethiopia. Moreover, there were significant positive correlation coefficients between most of the characters. This included the correlation between agronomic characters of primary interest in sorghum breeding such as plant height and days for 50% flowering and also between various characters and the altitude of the collection sites. The implications of the results in plant breeding, germplasm collection and conservation as well as the probable sources of the wide range of variation are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
9.
This study quantified the magnitude of heterosis in pearl millet (Pennisetum glaucum) topcross hybrids produced by crossing 16 diverse landraces and three high yielding open-pollinating varieties on two homozygous male-sterile lines. Hybrids and pollinators were grown in 12 year ×;location combinations in India that were grouped into three zones. Genetic components of variance quantifying the differences among these hybrids were estimated. The hybrids showed a conspicuous heterosis for grain yield, earliness and biomass yield but not for straw yield. The level and direction of heterosis for time to flowering depended strongly on the earliness of the male-sterile line. In the terminal drought stress zone hybrids made on the early maturing male-sterile line 843A had the highest level of heterosis for grain yield (88%). This was partly due to escape from terminal stress. In the other two zones the heterosis for grain yield was on average 30%. Heterosis for biomass yield and biomass yield per day was on average also positive in all three zones. For all traits, except time to flowering and biomass yield per day, pollinator effects were the only significant source of variation. Differences between hybrids were mostly caused by additive genetic effects. Significant amount of heterosis observed in landrace-based topcross hybrids for grain yield and other productivity-related traits suggested that substantial improvement in pearl millet productivity in and environments can be obtained by topcrossing locally adapted landraces on suitable male-sterile lines. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
10.
中国不同省份籼稻地方品种的指纹图谱分析   总被引:2,自引:0,他引:2  
【目的】通过对中国不同省份籼稻地方品种的SSR标记多样性分析,为中国籼稻地方品种的指纹图谱构建及其有效保护和利用提供理论依据。【方法】利用78对SSR引物,对中国14个省280份籼稻地方品种进行指纹图谱检测,分析不同省份籼稻地方品种间SSR标记遗传多样性差异、等位基因组成及其出现频率等。【结果】共检测到330个等位基因,每对引物等位基因数为2—12个,平均等位基因数为4.141个。RM336、RM334、RM264、RM297、RM204、RM248、RM444的等位基因数和有效等位基因数较多,分别在6和3以上,且遗传多样性指数较高,在1.4以上。78对SSR引物各等位基因的出现频率变异在0.18%—99.56%,RM338的A等位基因出现频率最高,RM131的E等位基因和RM276的F等位基因出现频率最低。RM338、RM308、RM484、RM29等44对SSR引物的某个等位基因在单个或多个省份籼稻地方品种中出现频率为100%。RM336、RM334、RM264、RM204、RM297、RM248、RM263、RM276、RM444、RM21、RM246和RM258等12对引物在多数省份中均表现为较高的遗传多样性。【结论】上述12对SSR引物适用于中国籼稻地方品种的指纹图谱构建。  相似文献   
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