Abstract

RAMON M, Miguel C et al. Association between varietal traits and damage caused by the sugarcane stemborer in portuguesa state, venezuela. Agronomía Trop. [online]. 2008, vol.58, n.2, pp.111-116. ISSN 0002-192X.

The sugarcane borer (Diatraea spp.) is the second major pest in Venezuela right after the sugarcane froghopper (Aeneolamia varia). The Venezuelan sugar cane program includes screening experimental clones at the final stages during the regional trials when percentage of exited internodes and percentage of bored internodes are recorded at harvest during three crops. However, concerns have been raised over effectiveness and confidence of these two traits in assessing the resistance to the borer. In order to identify varietal traits related to reaction of attacks by sugar cane borer and evaluate efficiency of currently used infestation index a correlation analysis for the data recorded in 12 years of sugar cane regional trials in Portuguesa State, Venezuela was conducted. The data analyzed revealed very low correlation between juice fiber content, stalk weight and stalk number and percentage of bored internodes (I.I.I.) and percentage of exited internodes (I.I.) indicating the useless of this traits in constructing a selection index for identifying resistant clones in a population. Also, no relationship between fiber content with resistance to Diatraea spp. can be confirmed from these results. However, a low but significant negative correlation was found between stalk diameter and I.I.I. (-0.105 P>0.0016). Diatraea damage showed a negative and significant degree of correlation with reduction of sugar content and juice and quality. High and positive correlations between I.I.I. and I.I. (0,892 P>0, 0001) may indicate the reliability of their use. Screening the gene bank in order to avoid the use of susceptible parents is a must.

Keywords : Sacharum spp; intensity of infestation; intensity of infestation index; Pearson,s correlation; INIA; varietal resistance.