小麦品种混种对白粉病的调控及其对部分产量性状及蛋白质含量的影响

对品种混合种植控制小麦白粉病的效果以及对小麦穗重、千粒重、蛋白质等指标的影响进行了研究,为混合种植控制白粉病提供理论依据和品种组合.在对37个小麦品种进行SSR多样性分析的基础上,选用8个生产品种（后备品种）,按品种数3、4、5、6、8进行组合,在田间以随机区组设计种植混播组合和单播小区,人工接种白粉菌,比较各小区中小麦白粉病的AUDPC值、穗重、千粒重和粗蛋白差异.结果表明,8个品种亲缘关系较远;4品种混种时AUDPC最小,穗重最重.26个品种混种组合中有防治效果的组合占到73.08％,相对防效为1.23％～56.65％;混种未对穗重和粗蛋白含量造成负面影响.品种多样性种植可以用做调控小麦白粉病的一项措施.

燕麦对冠锈病水平抗性的QTL定位

为了确定与燕麦冠锈病水平抗性基因相关的分子标记 ,建立了具水平抗病性的品系MN84 180 1- 1和感病品种 Noble- 2杂交的 F8群体 .该群体由 158个重组自交系组成 .用 112个 RFLP标记构建了其连锁图 ,该图由 17个连锁群 (A- Q)组成 ,另有 2 3个位点未连锁 ,大约覆盖了燕麦基因组的 1498.2 c M.重组自交系群体的抗病性鉴定分别在温室和田间进行 .用病斑面积占总叶面积的百分率(PPA)和病害发展曲线下的面积 (AUDPC)作为抗病指标 ,在田间试验中分别探测到 3个燕麦冠锈病水平抗性的 QTL,依次命名为 PRQ1,PRQ2和 PRQ3.这 3个 QTL分别位于连锁群 C,P和 N上 ,总共可解释 2 7%的表现型变量 .在温室试验中只探测到 PRQ1和 PRQ2两个 QTL,当用 AUDPC和 PPA分别作为抗病指标时 ,这两个 QTL可分别解释 32 %和 2 6

The Effect of Wheat Mixtures on the Powdery Mildew Disease and Some Yield Components

Mixtures composed of five wheat cultivars,Jingshuang 16,Jing 411,Jingdong 8,Lunxuan 987,and Baofeng 104,with different levels of resistance against powdery mildew were tested for their potential containment of the disease development in the field and for the influence on grain yield and the content of crude protein in the years 2007 and 2010.The plots were inoculated artificially with mixed isolates collected in the fields and propagated in the greenhouse and the disease was scored in 7 d interval during the two growing seasons.It was indicated that certain combinations,e.g.,Jingdong 8：Lunxuan 987,Jingdong 8：Baofeng 104,and Jing 411：Jingdong 8：Baofeng 104,showed positive efficacy on the mildew.The cultivar combinations tested in 2007 showed increase of grain yield,while most of the combinations tested in 2010 did not show the increase.The differences of the increases or decreases were not statistically significant except combinations Jing 411：Jingdong 8：Baofeng104,Jingshuang16：Jingdong8：Lunxuang 987 and Jingshuang 16：Jingdong 8：Lunxuan 987：Baofeng 104,which showed the decrease of the grain yield.The mixtures did not show influence on the content of crude protein in grain.More cultivar combinations need to be tested.

马铃薯晚疫病发病程度田间观察记录标准的探讨

目前用于马铃薯晚疫病发病严重程度的描述方法主要分为两类,一是直接计数法,即感病百分数法;二是分级计数法,包括病情指数法及CIP 9级分级法。基于以上描述方法,还可计算出病情发展曲线下的面积(AUDPC),对遗传材料的抗性进行评价。无论何种方法,准确估计和记录晚疫病病斑侵染面积占植株总面积的比例是非常重要的,即使是长期从事晚疫病研究的专业人员有时也会产生较大的偏差。利用标准图谱作为参照,可以有效降低科研人员的判断误差。所以,有必要建立一套标准的彩色图谱,供从事病害调查的技术人员参考,有效地提高对晚疫病发病程度的评估准确性。

紫外线对小麦叶锈病病菌流行学因素的影响

研究紫外线对小麦叶锈病病菌12-5-1384-1菌株和其诱变菌株1384-B-10-1孢子萌发率和流行学因素的影响。结果表明,紫外线对这2个菌株的影响表现一致,紫外线处理均使夏孢子萌发率降低,潜育期延长,侵染效率、产孢量及病情发展曲线下面积(area under disease-progress curve,简称AUDPC)显著下降,病斑扩展率最大值下降;紫外线处理后,与原始菌株相比,诱变菌株夏孢子的相对萌发率较高,侵染效率提高,病斑扩展率最大值延迟,产孢量和AUDPC升高。以上结果表明,诱变菌株对紫外线的容忍度比原始菌株大,即诱变菌株更适宜在紫外线越来越强的自然环境中生存。

Effect of Varieties and Fungicide Rate on Chocolate Spot (Botrytis fabae) Disease of Faba Bean (Vicia faba L.) at Tach Gayint District in South Gondar Zone, Amhara Region, Ethiopia

Faba bean is suffered with many biotic and abiotic factors. Chocolate spot disease, caused by Botrytis fabae is one of the biotic factors limiting yields of this crop resulting in yield losses up to 68% in Ethiopia. The experiment was conducted during 2020/2021 cropping season at Tach Gayint district, Ethiopia to determine the integration of faba bean varieties and fungicide rates on reducing chocolate spot disease. The experiment consisted of 12 treatments, viz. three faba bean varieties and four rate of Mancozeb fungicide in factorial arrangement. The experiment was laid out as randomized complete block design (RCBD) with three replications. Data was collected and analyzed. Results indicated that, disease incidence was reached at maximum percentage in all treatments on the last dates of assessment. But treatments were significantly difference in severity level. The least disease severity was recorded from varieties treated by 3.5 kg/ha of Mancozeb 80% WP with mean values Walki (12.7%), and (18.1% and 20.8%) on Gora and local variety respectively at the final dates of disease assessment. Similarly, the reduced AUDPC was also recorded from varieties treated by 3.5 kg/ha of Mancozeb 80% WP with mean values Walki (371.8% unit/day) and (539% and 686.4% days) on varieties Gora, and Local respectively. Whereas the maximum disease severity and AUDPC were obtained from unsprayed plots. Based on the results obtained, variety Walki treated with Mancozeb 80% WP at rate of 2.5 kg/ha and 3.5 kg/ha were effective to reduce the effect of chocolate spot disease for the study area.

Phenotypic and Molecular Characterization of Wheat Leaf Rust Resistance Gene <i>Lr34</i>in Iranian Wheat Cultivars and Advanced Lines

Lr34 is a vital gene in developing resistance to leaf rust, stripe rust, and powdery mildew of wheat. Providing simultaneous resistance to various pathogens has made this gene valuable in breeding for wheat resistance to many diseases. The present study investigates the csLV34 marker’s capability in diagnosing this locus in130 wheat commercial cultivars and advanced wheat lines from Iran, and assesses the impact of this gene on disease severity in field conditions. To assess the reactions of cultivars and lines which contained Lr34 under epidemic conditions of leaf rust, these cultivars were cultivated during the 2009 and 2010 cropping season. Of the 130 studied cultivars, 43 contained Lr34. Cultivars that were selected and studied in stress conditions had the most frequent presence of Lr34. It can be concluded that this gene plays a vital role in increasing the tolerance of cultivars under stress conditions. Lr34 seems to cause active transition of materials out of the cell. In addition to being resistant to several important diseases of wheat, Lr34 can increase tolerance to stresses such as salinity. Considering the calculated value for AUDPC (3%-440%/d) in cultivars containing Lr34, it seems that some cultivars contained additional resistance genes. The rate of infection in all cultivars, when presence of Lr34 was detected through the molecular marker, was lower than in other cultivars. Field results confirmed the results of the analysis using the csLV34b molecular marker.

Assessing Reactions of Genetically Improved and Local Cassava Varieties to Cassava Mosaic Disease (CMD) Infection in a Savannah Region of the DR-Congo

The responses of eight genetically improved and eight local cassava varieties to cassava mosaic disease (CMD) were evaluated under field conditions at two sites, in Eastern Kasa?, region of the DR-Congo). The varieties were planted using randomized complete block design with three replications. The rate of cuttings sprouted varied significantly from variety to variety and from location to location. Local varieties were severely infected than improved varieties throughout the trial period. In general, the level of CMD incidence for genetically improved varieties was below 15% while it reached 100% for the local cassava varieties six months after planting (MAP). This trend was also observed for the CMD severity and gravity. The mean scores for CMD severity were 2 and 3.6 for genetically improved and local varieties, respectively at 6 MAP. CMD gravity for improved varieties was below 21% for genetically improved varieties and exceeded 85% for local varieties at the end of trials. Area Under the Severity index Progress Curve (AUSiPC) and Area Under Disease Progress Curve (AUDPC) estimates confirmed that improved varieties were moderately infested comparatively to local varieties. Molecular analysis is being conducted to determine the genetic variability and complexity of the cassava mosaic virus strains involved.

Effect of Various Soil Media on Disease Severity of <i>Fusarium</i>Wilt in Watermelon

Fusarium wilt is a major disease of watermelon (Citrullus lanatus) caused by Fusarium oxysporum f. sp. niveum (Fon). Use of host resistance is the most effective management strategy for the disease, and a major objective for breeding programs. Screening assays rely on the ability to discriminate resistant and susceptible genotypes in segregating populations. However, complex interactions between Fon and the soil environment can influence symptom development and disease severity rating. In the current study, severity of Fusarium wilt (race 1) in sand-peat (1:1 v/v), sand-perlite (1:1), sand-peat-vermiculite (4:1:1), peat-perlite (1:1) and Fafard 3B potting media was compared among five watermelon cultivars: Calhoun Gray (resistant), SunSugar (resistant), Allsweet (moderately resistant), Sugar Baby (susceptible) and Charleston Gray (susceptible). Plant biomass (average dry weight/plant) was lowest in peat-perlite (1.67 g) and sand-peat (2.16 g), and was significantly different (α = 0.05) from that of sand-perlite (3.48 g), sand-peat-vermiculite (4.94 g) and Fafard 3B (6.90 g). Conversely, disease severity [area under disease progress curve (AUDPC)] across cultivars was significantly higher in peat-perlite (AUDPC = 62.96) and sand-peat (AUDPC = 40.87), than in sand-perlite (AUDPC = 11.55), sand-peat-vermiculite (AUDPC = 10.67) and Fafard 3B (AUDPC = 9.29). Consistent discrimination (α = 0.05) of resistant and susceptible cultivars was realized in sand-peat-vermiculite and Fafard 3B, but was not possible in peat-perlite, sand-peat and sand-perlite. Collectively, these findings support suitability of sand-peat-vermiculite and Fafard 3B for routine screening of Fusarium wilt resistance in watermelon.

Assessment on early blight of potato in order to compare the two methods<i>in vitro </i>using pathogenic fungi <i>Alternaria solani</i>

Potato (Solanum tuberosum) early blight, caused by Alternaria solani is one of the most destructive fungal foliar diseases. This research was done in order to study methods comparison of evaluation by culture filtrate of A. solani in in vitro condition for selecting resistance cultivars to early blight. Plantlets of potato viruse free were obtained from the National plant gene bank of Iran, and were inoculated in vitro methods with a culture filtrate of A. solani. In in vitro selection by droplet of culture filtrate method, leaflet received a 10 μl droplet of the A. solani culture filtrate and in in vitro selection by direct using of culture filtrate method, plantlets were placed in test tubes that include 5 μl A. solani culture filtrate. The experimental design was factorial on basis of completely randomized design (CRD) with two factors, three replications and six genotypes. During droplet method assay, the A. solani symptoms appeared 1 - 2 days until 6 days and during direct method they appeared 2 - 3 days until 6 days. The AUDPC values were submitted to the analysis of varience (ANOVA) and AUDPC means were compared by using Duncan test (α = 0.01%). In each method, significant difference among potato cultivars was observed for disease to early blight (p < 0.01). Results show that casmos cultivar is susceptible for resistance to early blight and in vitro methods experiment had the same result.

品种混种控制小麦白粉病及其对小麦产量和蛋白质含量的影响

研究品种混种对控制小麦白粉病的效果以及对产量及蛋白质含量的影响,可为利用品种多样性持续控制白粉病提供理论依据及技术支持。2011—2012和2012—2013年度选用抗病性不同、遗传背景有较大差异的8个小麦生产品种,按每个组合3-8个品种进行田间混种,人工接种白粉菌混合菌株,比较品种混种对小麦白粉病的病害流行曲线下面积以及小麦产量、粗蛋白含量和千粒重的影响。结果表明,混种组分品种的数量对防效有影响,其中以4个品种混种的防病效果最好,但当品种数达到7个及以上时,混种也显示出较好的控病效果。2011—2012年度混种组合中有防效的占42.4%,相对防效为1.2%-26.8%,约50%的混种组合表现增产,增产幅度为0.2%-14.6%;2012—2013年度有防治效果的组合占75.0%,相对防效1.8%-45.4%,约71%的混种组合表现增产,增产范围为0.9%-16.6%。供试品种中周麦18总体表现最好,并且与其他品种混种后对控制小麦白粉病、增加产量和粗蛋白含量均有正向效应。不同混种组分品种间存在互作,其互作对病害控制及产量均有影响。

不同烟草品种在重庆市彭水地区的青枯病抗性比较

烟草青枯病是由青枯雷尔氏菌(Ralstoniasolanacearum)引起的土传细菌性病害,常造成重大经济损失,筛选高抗、良好生态适应性的种质资源是选育青枯病抗病品种、防治烟草青枯病的重要基础.为明确不同烟草种质对青枯病抗性的差异,筛选出优良的抗性材料,本研究在彭水田间自然发病地块连续2年(2020年和2021年)对不同烟草品种进行田间抗病评价.结果表明,供试抗性烟草品种的病程发展曲线下面积显著低于感病对照品种红花大金元、长脖黄、翠碧一号;依据抗性等级划分,在2年的发病高峰期(2020年8月15日和2021年8月22日),均表现抗病的供试品种为“岩烟97”和“6036”,“岩烟97”连续2年的病情指数分别为12.73和3.89,“6036”连续2年的病情指数分别为3.70和15.65.综合来看,本研究通过抗性评价明确了“岩烟97”和“6036”对青枯病的抗性最强,且抗性稳定,育种潜力较大,可作为后续高抗品种的参考材料.

小麦品种多样性对白粉病及产量和蛋白质的影响

对品种多样性控制小麦白粉病的效果以及对产量和蛋白质的影响进行了研究,为利用品种多样性控制白粉病提供理论依据和技术支持。采用SSR技术分析5个小麦品种的亲缘关系;2008年和2009年按组合所含品种数为2、3、4和5个进行组合,在田间种植混种组合和单播小区,人工接种白粉菌,比较各小区中小麦白粉病的AUDPC值、产量和蛋白质变化。结果表明,5个品种亲缘关系相对较近;2个品种混合时以抗感搭配较好,随着抗病品种比例增加控病效果增强;2008年混合种植中有防治效果的组合占54.55%,相对防效为10.02%～47.58%,2009年有防治效果的组合占23.08%,相对防效在1.85%到18.96%之间;在适当的组合中,如京冬8号/轮选987、京双16/京411/京冬8号对小麦白粉病有控制效果,混种不会影响产量和蛋白质含量;当有大量能克服本地品种抗性的外来菌源时混合种植的控病效果降低。品种多样性可以用做防治小麦白粉病的一项措施。