Abstract

SOLIS-MOYA, Ernesto; HUERTA-ESPINO, Julio; VILLASENOR-MIR, H. Eduardo  and  AGUADO-SANTRACRUZ, G. Armando. Stripe rust, phenology, yield and yield components in bread wheat (Triticum aestivum L.). Agrociencia [online]. 2007, vol.41, n.5, pp.563-573. ISSN 2521-9766.

In El Bajío, México, yellow stripe rust (Puccinia striiformis f. sp. tritici Eriks.) is the main problem of the commercial bread wheat (Triticum aestivum L.) crops in the fall-winter cycle. The present study was carried out to evaluate the effect of yellow stripe rust on the phenology of the bread wheat plant, yield and its components. Four experiments were conducted on two sowing dates (December 1 and 16 of 1998): two with the pressure of yellow stripe rust and two free of it by means of chemical control. An evaluation was made of 250 genotypes, of which 240 were families F5 derived from seven cycles of recurrent selection and the other ten were commercial varieties. The experimental design was alpha lattice, of 25 incomplete blocks, sublots of 10 genotypes and two replicates. According to the percentage of severity, the materials were classified in five categories: 0-20, 21-40, 41-60, 61-80 and 81-100. The rust reduced the cycle of the wheat from the dough grain stage (p≤0.05) and the yield in 41.7 and 43.3% (p≤0.05) on the first and second date of sowing, in the genotypes with severity from 81 to 100%. In the optimum production environment (December 1) the yellow stripe rust reached 100% severity in the susceptible genotypes, in the milky grain stage, affecting only the grain weight component. In the sowing of December 16, this condition was reached at an earlier stage (75% of grain formed), which reduced the number of grains per square meter and the grain weight. Of the components that generate the number of grains per surface unit (grains per spike and spikes per square meter), the number of grains per spike was affected to a higher degree (p≤0.05), due to the fact that the highest severity of the rust occurred after heading, stage in which the number of fertile spikes per surface unit had already been established.

Keywords : Biomass; harvest index; number of grains per square meter; yellow stripe rust; grain weight.

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