Inheritance of Latent Period of Puccinia recondita in Wheat

Crop Science ◽  
1997 ◽  
Vol 37 (3) ◽  
pp. 748-756 ◽  
Author(s):  
Gregory Shaner ◽  
George Buechley ◽  
Wyman E. Nyquist
1999 ◽  
Vol 3 (1) ◽  
pp. 20
Author(s):  
Luis Fernando Campuzano Duque

<p>Se realizó este estudio para determinar tres componentes epidemiológicos de la roya de la hoja: período de latencia, tasa de desarrollo de la enfermedad y área bajo la curva de progreso de la roya de la hoja, también, la clase de acción génica y heredabilidad implicados en el tipo de resistencia denominada "desarrollo lento" de la roya de la hoja en tres variedades de trigo: Pavón 76, Nacozarí 76 y Hermosillo 77 ;trabajo que se llevó a cabo en el Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT),localizado en Texcoco, Estado de México, México. Para comenzar, se obtuvieron seis cruzas simples posibles de éstas tres variedades con una variedad susceptible carente de genes de resistencia, denominada Jupateco 73<sup>S</sup>. Los progenitores y 74 familias F<sub>5</sub>, de cada una de las seis cruzas, fueron sembradas en un diseño de bloques completos al azar con un arreglo de parcelas divididas con tres repeticiones. Los resultados indicaron que en las 3 variedades el período de latencia fue largo y la tasa de desarrollo de la enfermedad baja. El análisis de aptitud combinatoria indicó que los efectos de tipo aditivo fueron los más importantes. La heredabilidad en sentido restringido en promedio de todas las cruzas y en cada una de ellas fue alta. No se encontró asociación entre el área bajo la curva de progreso de la roya de la hoja con madurez fisiológica y la altura de la Planta.</p><p><strong><br /></strong></p><p><strong>Inheritance and Components of slow rusting to leaf rust (Puccinia recondita f.sp.tritici) in wheat.</strong></p><p>In order to determine the latent period and rate of development of the disease, the area under the leaf rust progress curve, the type of gene action, and heritability implicated in the type of resistance called "slow rusting" of the leaf rust in the Pavon 76, Nacozari 76 and Hermosillo 77,was carried out this work at the International Maize and Wheat Improvement Center (CIMMYT),located in Texcoco, State of Mexico, Mexico. All possible single crosses were entered into these three varieties with a susceptible lacking genes resistance, called Jupateco 73<sup>S</sup>. Parents and 74 F<sub>5</sub>, Families of each cross were planted in a plot randomized block design with three replications. The results indicate that in the 3 varieties the latent period was long and the rate of disease development was low. Combining ability analysis indicates that the additive variance was the most important. The narrowsense heritability as an average of all crosses, as well as in each cross was high. There was no relationship between the area under the leaf rust progress curve and Plant maturity or height.</p>


1997 ◽  
Vol 87 (2) ◽  
pp. 170-176 ◽  
Author(s):  
Jeffrey S. Lehman ◽  
Gregory Shaner

Wild-type fungal population 851-WT was selected for shortened latent period on cv. CI 13227 for five uredinial generations to study the adaptation of Puccinia recondita f. sp. tritici to partially resistant wheat cultivars. Differences among wild-type and selected populations for traits contributing to parasitic fitness (i.e., latent period, infection frequency, and uredinium area and growth rate) were assessed in monocyclic infection experiments on susceptible cv. Monon and partially resistant cvs. Suwon 85, Sw 72469-6, L-574-1, and CI 13227. Differences were greatest among fungal populations on cv. CI 13227. The mean latent period of selected population 851-C5 was 2 days shorter (~20%) than that of wild-type population 851-WT. In addition, uredinia of population 851-C5 expanded 40% faster and produced ~75% more urediniospores. On cv. L-574-1, the selected population was also more fit than the wild-type progenitor for initial uredinium area and growth rate and cumulative urediniospore production. In contrast to wild-type and selected populations on cvs. CI 13227 and L-574-1, selected population 851-C5 on cv. Monon produced slower expanding uredinia with fewer urediniospores than did population 851-WT on Monon. These results show that variation in the latent period of P. recondita f. sp. tritici populations is partially under genetic control and wild-type P. recondita f. sp. tritici populations contain members reproductively more fit on partially resistant wheat cultivars but not necessarily on susceptible cultivars. Such members are capable of partially overcoming quantitative host resistance.


Author(s):  
R. F. Bils ◽  
W. F. Diller ◽  
F. Huth

Phosgene still plays an important role as a toxic substance in the chemical industry. Thiess (1968) recently reported observations on numerous cases of phosgene poisoning. A serious difficulty in the clinical handling of phosgene poisoning cases is a relatively long latent period, up to 12 hours, with no obvious signs of severity. At about 12 hours heavy lung edema appears suddenly, however changes can be seen in routine X-rays taken after only a few hours' exposure (Diller et al., 1969). This study was undertaken to correlate these early changes seen by the roengenologist with morphological alterations in the lungs seen in the'light and electron microscopes.Forty-two adult male and female Beagle dogs were selected for these exposure experiments. Treated animals were exposed to 94.5-107-5 ppm phosgene for 10 min. in a 15 m3 chamber. Roentgenograms were made of the thorax of each animal before and after exposure, up to 24 hrs.


Author(s):  
Irving Dardick

With the extensive industrial use of asbestos in this century and the long latent period (20-50 years) between exposure and tumor presentation, the incidence of malignant mesothelioma is now increasing. Thus, surgical pathologists are more frequently faced with the dilemma of differentiating mesothelioma from metastatic adenocarcinoma and spindle-cell sarcoma involving serosal surfaces. Electron microscopy is amodality useful in clarifying this problem.In utilizing ultrastructural features in the diagnosis of mesothelioma, it is essential to appreciate that the classification of this tumor reflects a variety of morphologic forms of differing biologic behavior (Table 1). Furthermore, with the variable histology and degree of differentiation in mesotheliomas it might be expected that the ultrastructure of such tumors also reflects a range of cytological features. Such is the case.


Crop Science ◽  
1985 ◽  
Vol 25 (2) ◽  
pp. 262 ◽  
Author(s):  
J. G. Moseman ◽  
E. Nevo ◽  
Z. K. Gerechter-Amitai ◽  
M. A. El-Morshidy ◽  
D. Zohary

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