Authors:Tomohiro Ban, Naoyuki Kawad, Akira Yanagisawag and Akane Takezaki
We review and report the progress of germplasm enhancement for FHB resistance in Japan. Since 1970s, numerous wheat and barley germplasms have been screened for FHB resistance in intensive national breeding system. Resistance to FHB varies not only among wheat varieties but also their wild relatives, but no accession has been found to be completely immune. Spring wheat varieties from the Japanese and Chinese gene pools were screened and analyzed for their genetic diversity. It showed the uniqueness of the Japanese gene pool, and its distinction from the Chinese one. We traced the pedigrees of resistant wheat varieties to examine genetic diversity and potential in Japanese breeding programs. ‘Shinchunaga’, in addition to ‘Saitama 29’ and local varieties such as ‘Nobeokabouzu-komugi’ and ‘Nyubai’, is considered to the main donors for moderate resistance to FHB in many Japanese commercial varieties. Another contributor ‘Sumai 3’ from China made gains of the resistance level for modern Japanese commercial varieties. These results showed the advancement in development of new varieties with pyramiding of genes to enrich FHB resistance and low level of mycotoxin contamination in the breeding programs.
Authors:W. Abera, H. Shimelis, J. Derera, M. Worku and M. Laing
Productivity of maize (Zea mays L.) is curtailed by a number of stress factors, predominantly by diseases and insect pests. The Northern leaf blight disease of maize caused by Exserohilum turcicum (Pass.) Leonard and Suggs inflict significant yield losses in the humid tropical regions. The objectives of this study were to determine the leaf blight response of 50 elite maize inbred lines developed for the mid-altitude, sub-humid tropics and to select promising parents for resistance breeding. Inbred lines were evaluated in the field using a 5 × 10 alpha lattice design with three replications. Plants were artificially inoculated at the 4–6 leaf stages during 2011 and 2012. Data on disease severity and incidence, AUDPC and yields were recorded. Inbred lines had significant differences for E. turcicum reactions, and were classified into resistant, intermediate or susceptible categories. The mean disease severity ranged from 2.04% for the inbred line 136-a to 3.25% (Kuleni-C1-101-1-1-1). The upper leaf area infection of inbred lines 143-5-I and 136-a was 3.3%, while the line Kuleni-C1-101-1-1-1 displayed 100% infection. Further, 136-a developed the lowest AUDPC score at 238, whereas Kuleni-C1-101-1-1-1 had the maximum at 700. Overall, inbred lines CML202, 144-7-b, 139-5-j, 136-a, 30H83-7-1-1-1-2-1, ILoo’E-1-9-1-1-1-1-1 and 142-1-e, were identified as promising sources of resistance against E. turcicum. The selected elite inbred lines would be recommended for use in general varietal development, disease management and to enhance maize productivity, in the mid-altitude sub-humid tropics.
The new stem rust strain, Puccinia graminis f. sp. tritici — Ug99, has been a rising threat since the alarm was rung in Uganda in 1998. The genetic and breeding dimensions of research against this disease include the development of vigorous molecular markers, the identification and introgression of multiple resistance genes, the translocation of alien chromosomes, the enrichment of breeding lines with crossability alleles and the development of interspecific hybrids. Resistance genes have been identified in the primary wheat gene pool and in alien sources such as Aegilops spp., Dasypyrum villosum, Secale cereale, Hordeum vulgare and Oryza spp. and some of these sources have been used to confer resistance as a function of single or multiple gene effects. Realizing the potential disaster if Ug99 and related variants break out in other regions, wheat-producing countries are characterizing their germplasm and improving their stem rust race tracking systems. Equally important is “appropriate genetic management”, i.e. the use of currently effective resistance genes in such a way that the evolution and adaptation of new virulence will be deterred. This review will summarize the recent research advances and future perspectives in setting effective genetic barriers vis-à-vis the seemingly intractable spread and evolution of Ug99.
Authors:C. Bolduan, J. Montes, B. Dhillon, V. Mirdita and A. Melchinger
Ear rots of maize caused by
spp. reduce grain yield and produce mycotoxins, which are harmful to humans and animals. To breed maize cultivars resistant to
spp., reliable large-scale phenotyping is essential. Our objectives were to (i) examine the precision of the ELISA method for determination of important mycotoxins, namely deoxynivalenol (DON) and fumonisins (FUM), (ii) evaluate the potential of near-infrared reflectance spectroscopy (NIRS) to estimate concentrations of DON and FUM in grain produced in inoculated maize plants, and (iii) compare the efficiency of ELISA, NIRS, and visual rating of disease severity for estimation of mycotoxin concentrations. Insignificant variation was observed between duplicate evaluations of DON and FUM by ELISA, showing the high repeatability of this method. DON and FUM determinations by ELISA were more closely correlated with mycotoxin concentrations predicted through NIRS than with visual rating of disease severity. For the prediction of DON, NIRS had very high magnitude of the coefficients of determination of calibration and cross validation (R
= 0.90–0.88). Thus, NIRS has a promising potential to predict DON concentration in grain samples of inoculated maize genotypes evaluated in resistance breeding programs.
Authors:R. Hajianfar, Zs. Polgár, I. Wolf, A. Takács, I. Cernák and J. Taller
blight caused by Phytophthora infestans : An overview of pathology and resistancebreeding. Plant Disease 96, 4–17.
Kozik E. U.
Potato and tomato late blight caused by Phytophthora infestans: An overview of pathology and
Authors:C Szőke, Z. Zsubori, I Pók, F. Rácz, O. Illés and I. Szegedi
: Rezisztencianemesítés lehetőségei a kukorica kártevőivel szemben. (Resistancebreeding against maize pests.) Agrártudományi Közlemények , 37 , 183-186.
Rezisztencianemesítés lehetőségei a kukorica kártevőivel szemben. (Resistancebreeding
Authors:István Virág, K. Szalay, C. Szőke, G. Milics, L. Marton and M. Neményi
Kernel samples of two maize hybrids (46308 and 463017) with different levels of resistance to Fusarium ear rot were collected from artificially and naturally infected plants. The spectral characteristics of the samples were analysed with an ASD Fieldspec 3 MAX spectroradiometer in the wavelength range of 350 to 2500 nm using an ex situ method. The different extents of artificial and natural Fusarium infection on the maize kernels resulted in spectral differences detectable with a spectroradiometer. The data showed that for both genotypes the level of Fusarium infection generated by artificial inoculation was significantly higher than that caused by natural infection over a wavelength range of 2030 to 2080 nm. Principal Component Analysis (PCA) on the data set for this range revealed that the first component explained 77.0% of the variability for hybrid 46308 and 97.0% for hybrid 46317.
Authors:Karin Huber, Maria Buerstmayr and Hermann Buerstmayr
The aim of the project is the detection, genetic mapping and characterization of quantitative trait loci (QTL) that confer resistance against
head blight in a resistant line of
Authors:D. Soresi, D. Zappacosta, A. Garayalde, I. Irigoyen, J. Basualdo and A. Carrera
Langdon(Dic-3A)-10 line carrying the QTL Qfhs.ndsu-3AS from T. turgidum ssp. dicoccoides that confers Type II resistance to Fusarium head blight (FHB) was crossed with Argentinean durum wheat cultivars. F4 progeny were screened with the microsatellite locus Xgwm2, tightly linked to the Qfhs.ndsu-3A region. Reaction of these plants and parents to FHB was evaluated at 7, 14 and 21 days post-inoculation (dpi) with F. graminearum; severity (% symptomatic spikelets/spike) and AUDPC (area under disease progress curve) were calculated. F4 progeny carrying the resistance allele in heterozygous or in homozygous condition showed significantly lower scab damage at 21 dpi and slower progress of disease than cultivated parents. Our results indicate that the resistance Qfhs.ndsu-3AS has a stable dominance expression in genetic backgrounds of durum cultivars and demonstrate that the linked microsatellite is an effective molecular tool for resistance screening. This work offers valuable information for Qfhs.ndsu-3AS utilization in wheat breeding programs.