小型植保无人机超低量喷雾对荒漠绿洲麦区小麦白粉病的防治效果

研究小型植保无人机超低量喷雾对小麦白粉病的防治效果,为科学使用小型植保无人机防控小麦病害提供指导。采用随机区组的方法,定点调查各处理小麦白粉病发生情况,评价供试药剂对小麦白粉病的防治效果。结果表明,240 g/L氯氟醚·吡唑酯SC 180 g/hm²、19%啶氧·丙环唑SC 199.50 g/hm²和 23%醚菌·氟环唑 SC 103.50 g/hm²添加增效剂迈飞对小麦白粉病具有较好的防效,防效分别为77.88%、74.23%和 73.26%。42%苯菌酮 SC 189.00 g/hm²、430 g/L戊唑醇悬浮剂SC 129.00 g/hm²、75%肟菌·戊唑醇 WG 202.50 g/hm²和 40%腈菌唑 WP 120.00 g/hm²添加增效剂迈飞对小麦白粉病防效在60.90%～65.72%之间。7 种药剂均可用于小型植保无人机超低量喷雾防治小麦白粉病,为了减缓抗药性的产生,建议在生产上轮换使用。     

The Inheritance of Resistance to Septoria Glume Blotch II. The Wild Wheat Species Aegilops speltoides

The inheritance of resistance in the wild wheat species Ae. speltoides L. to Septoria glume blotch (Septoria nodorum Berk.) was investigated. It was characterized by two parameters measured on detached leaves, namely lesion size (LS) and length of latent period (LP), and by the severity of the disease under field conditions (DS). The genetic analysis was based on the F₁ and F₂ generations of a 4 × 4 diallel cross between four Ae. speltoides accessions showing differential resistance to the pathogen. The three parameters of resistance were highly correlated. Considerable heterosis for resistance was found for each of the parameters in most of the diallel combinations. The estimates of broad-sense heritability were moderately high (0.50 — LS, 0.60 — LP, 0.52 — DS), while the estimates of narrow-sense heritability were low (0.16 for LS, 0.20 for LP, 0.25 for DS). There were no indications for genie interaction. It is suggested that the resistance is controlled by at least two genes with over-dominance of the alleles for higher resistance. Highly resistant Ae. speltoides accessions are a potential source of germplasm for improving the resistance of cultivated wheats to Septoria glume blotch. The possibility of using dominant alleles for resistance in hybrid cultivars is discussed.     

Genetics of multiple disease resistance in a doubled-haploid population of barley

The barley accession Q21861 possesses resistance to the stem-rust (Puccinia graminis f.sp. tritici), leaf-rust (P. hordei), and powdery-mildew (Blumeria graminis f.sp. hordei) pathogens. An anther-culture-derived doubled-haploid population was produced from F₁ plants from a cross of this accession and the susceptible breeding line SM89010 as a means of rapidly and efficiently determining the genetics of multiple disease resistance. The doubled-haploid population segregated 1:1 (resistant:susceptible) for resistance to the stem rust pathotype QCC indicating the involvement of a single resistance gene, rpg4. Two-gene (3:1) and one-gene (1:1) segregation ratios were observed for resistance to the stem-rust pathotype MCC at low (23–25°c) and high (27–29°C) temperature, respectively. These different segregation patterns were due to a pathotype × temperature interaction exhibited by rpg4 and Rpg1. another stem-rust-resistance gene present in Q21861. One-gene and two-gene segregation ratios were observed in reaction to the leaf rust and powdery mildew pathogens. These data demonstrate the utility of doubled haploid populations for determining the genetics of multiple disease resistance in barley.     

Harmful winter wheat diseases and possibilities for their integrated control in Latvia

Decision support systems based on control thresholds are an important part of integrated disease control systems in winter wheat. Various warning and forecast systems have been developed in different countries (in Latvia – under the framework of Danish-Baltic joint project ‘Development and Implementation of an Internet-based Decision Support System for Integrated Pest Management’), but results were contradictory. The aim of this investigation was to identify the possibilities for integrated disease control under intensive management of winter wheat. Different schemes of fungicide treatment, including a decision support system, were tested in field trials from 2008 to 2012 in two places. Leaf blotches caused by Pyrenophora tritici-repentis and Zymoseptoria tritici are recognised as the most harmful wheat diseases in Latvia. The total impact of diseases, which was calculated as area under disease progress curves, was affected by the year and the scheme of fungicide treatment. Significantly higher yields were obtained in treatments with fungicide application, but differences between control strategies were not significant. The obtained results confirmed that two fungicide applications are not necessary (except certain cases). The results suggest that recommendations should be based on the disease incidence on the third or second leaf of wheat.     

Variations in pathogenicity patterns ofMycosphaerella graminicola withinTriticum spp. in Israel

Summary Pathogenicity patterns of 42Mycosphaerella graminicola (Septoria tritici) isolates secured from the major wheat growing regions in Israel, were assessed on seedlings of 16 bread and durum wheats. The spring bread wheat cultivar Titan (CI12615), the winter bread wheats Bezostaya 1, Kavkaz, NE7060 and the durum wheats Nursit 163 and Zenati Bouteille, all exhibited a high level of resistance. Significant cultivar × isolate interactions were recorded for isolates from the different regions in relation to the response of the 16 cultivars organized in 6 reponse classes to the test isolate ISR8036. Number of genes for resistance in the 16 cultivars was estimated, based on the assumption of a gene-for-gene relationship. Twelve complementary genes were hypothesized in the 42M. graminicola isolates × 16 wheat cultivars matrix. There was considerable variation in virulence frequencies between regions and between locations within the same region. The overall frequency of Bezostaya-Kavkaz virulence was low throughout the country (5–7%). The frequency of designated hypothesized virulence genes VST OLAF, VST COLOTANA, VST IAS 20 in Israel, was high in most locations. The reported analytical approach enables the identification of virulence hot-spots and assists in designing breeding for resistance strategies.     

Heading date and resistance to septoria tritici blotch in wheat not genetically associated

Nineteen cultivars, with large differences in heading date, were evaluated for their response to septoria tritici blotch in two experimental setups in Njoro, Kenya. Due to the more or less constant temperatures during the growing season and the overhead irrigation applied the epidemic conditions were similar over the whole observation period for the early and late cultivars. In experiment 1 the cultivars were assessed for disease severity at the same moment irrespective of the developmental stage, while in experiment 2 the cultivars were assessed at the same developmental stage. Measured at the same time, the disease severity was highest in the early maturing cultivars and lowest in the late maturing cultivars (r = –0.78). When assessed at the same development stage the disease build up was independent of heading date (r = –0.10) but strongly dependent on resistance level. There were no indications that early heading cultivars were more susceptible than late heading cultivars. This revised version was published online in July 2006 with corrections to the Cover Date.     

Race Specific Powdery Mildew Resistance in 31 Northwest European Wheat Cultivars

Race specific powdery mildew resistance in 23 winter wheat cultivars, eight spring wheat cultivars, and 14 lines/cultivars possessing known powdery mildew resistance genes, has been studied by analyzing host/pathogen interactions. The cultivars were tested as intact seedlings, and as detached primary leaf segments on water agar; both methods revealed reproducible and concordant results. The 45 cultivars/lines were divided into 24 resistance spectra according to the patterns of reaction to the powdery mildew isolates used. Of the 31 cultivars investigated, eight did not possess any of the resistance genes detected, and the remaining 23 were divided in 16 resistance spectra. The race specific resistance of nine cultivars was conferred by the single resistance genes Pm2, Pm4b, Pm5/Ml-i: or Pm6, while the race specific resistance of 14 cultivars was conferred by 2, 3, 4 or 5 genes in combination.     

Inheritance of the Powdery Mildew Resistance Mlk in Wheat

The inheritance of the Mlk powdery mildew resistance originating from ‘Heine 2174.50’ was analyzed by crossing the Mlk resistant cultivar ‘Ralle’× cv. ‘Amor’ (highly susceptible) and vice versa and by observing the reactions of F₁- and F₂-plants after inoculation with two different Mlk avirulent powdery mildew isolates. In all cases, a 3 (resistant): I (susceptible) segregation was found in F₂. The reactions of the F₂plants against the two powdery mildew isolates were identical in each case. Therefore, it is supposed that one dominant resistant gene is responsible for the resistant reactions against these two isolates. These results support the earlier assumption of Heun and Fischbeck (1987b) that the whole Mlk resistance pattern is controlled by a single gene.     

Disease Law and Forecasting of the Needle Blight ofPinus sylvestris var. mongolica

IntroductionNeedleblightofPinussylvcsIrisvarmongolicaisoneofthemaindiseaseonPinus3:VlvesIrlAvar.mongolicawhichisanativesPeciesinthearcabetWecnHulunbcirgrasslandandforest.Thisdiscaseisnotcdforscriousinfestation,fastspreadanddifficulttobecontrolled.Inthepas…