Leaf diseases, healthy green area and kernel weight in different wheat cultivars

Abstract

This paper aimed to find out correlations between the severities of incident leaf diseases, the duration of photosynthetic active green area and the weight of wheat grains. Wheat cultivars BR 23, Embrapa 16 and BRS 179 were used in the experiment, carried out in the experimental area of the Embrapa -  Wheat Research National Center, in the municipality of Passo Fundo, Rio Grande do Sul state. Each cultivar was sown in two plots during the years of 2003 and 2004. In one of the plots, a large spectrum fungicide was sprayed three times during the crop vegetative cycle, to keep it free of leaf diseases. The evaluations were carried out weekly in five plants randomly collected in each plot. Data was submitted to statistical analysis using program “R”. The results showed that, in 2003, the dry weight of the vegetative parts decreased, and a strong correlation (r= 0.96) was observed between the duration of the green area and the wheat grain weight. On the other hand, in 2004 this trend was not evidenced, showing a moderate correlation (r= 0.48) between the duration of the green area and the grain weight. The correlation between the weight of vegetative plant parts and the weight of grains depends on the leaf diseases intensity and, therefore, is variable according to the climatic conditions.