E1 presente trabajo se realizo en Patzcuaro, Edo de Michoacan, Mexico, durante el ciclo de verano 1992. Se estudio espigamiento, madurez, altura de planta, peso hectolitrico, rendimiento y Coeficiente de Infeccion (C. I.) por septoriosis. Con base en el analisis de componentes principales y multivariados, las caracteristicas de rendimiento, espigamiento, madurez, altura y C.I. explicaron la variabilidad existente entre 22 genotipos y permitio formar 7 grupos. Se observo tolerancia a Septoria tritici en las lineas CMH78A.544, F30081, F28977, CM82368, CMH 83.262 y CM96251. Con base en la ecuacion de regresion, por cada dia de retraso en el espigamiento, el C.I. disminuye en 1.4 porciento y por cada centimetro menos en la planta, el C.I. aumenta en 1.9 porciento. I>s perdidas de rendimiento variaron del 22.1 a 70.8 porciento calculandose en base a la proteccion quimica. No existio una relacion directa entre las perdidas de rendimiento y el C.I.|The research presented here was carried out in Patzcuaro, Michoacan, Mexico, in the 1992 summer crop cycle. The following traits were studied: days to heading, days to maturity, plant height, test-weight, grain yield, and Coefficient of Infection (C.I.) for septoria. Principal component and multivariate analysis of the data indicated that the variability between the 7 groupings of 22 genotypes was explained by grain yield, days to heading, days to maturity, plant height, and C.I. Tolerance to Septoria tritici was observed in the following lines: CMH78A.544, F30081, F28977, CM82368, CMH83.262 and CM96251. Regression analysis showed that for each day heading was delayed, the C.I. value dropped 1.4 percent. C.I increased by 1.9 percent for every centimeter drop in plant height. Yield losses varied between 22.1-70.8 percent, relative to the control treatment protected with fungicide. No direct correlation was observed between yield losses and C.I.

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AGRIS 9602|R95PROCE

CIMMYT Publications Collection