Broad-Sense Heritabilities, Genetic Correlations, and Selection Indices for Sugarcane Borer Resistance and Their Relationship to Yield Loss

MILLIGAN S; BALZARINI M; WHITE W

CROP SCIENCE

High Wire Press Stanford Univeristy

Año: 2003 p. 1729 - 1735

0011-183X

The sugarcane borer ([Diatraea saccharalis (Frabricius)] causes significant damage to sugarcane (Saccharum sp. hybrid), rendering cultivar resistance important. Researchers assess borer induced damage using up to five different measures: percent bored internodes, percent exited internodes, pupation success, moth production, and a damage rating. The inheritance of the different damage measures and the best approach to integrate the different variables into a simplified damage-resistance assessment has not been well studied. Furthermore, the relationships of the damage traits to sugar production have not been comparatively assessed.  We planted a replicated, two-location test of 28 clones typical of the selection stage screened  for borer resistance in the Louisiana sugarcane breeding programs. We recorded the five  measures together with sucrose production and its components. Using appropriate variance components, the heritability, expected response to selection, and genetic correlations among the traits were used to construct selection indices of all combinations of the five damage traits studied. We used the regression coefficients of the damage traits on sucrose production as economic weights. The indices indicated that percent bored internodes was the most effective single trait to reduce sugarcane borer damage. If data collection costs were considered, then the subjectively assessed damage rating was the most expeditious of the traits examined. High correlation values among several of the traits lead to the observation that inclusion of more than the bored internode, exited internodes and the damage rating in an index were unnecessary.Diatraea saccharalis (Frabricius)] causes significant damage to sugarcane (Saccharum sp. hybrid), rendering cultivar resistance important. Researchers assess borer induced damage using up to five different measures: percent bored internodes, percent exited internodes, pupation success, moth production, and a damage rating. The inheritance of the different damage measures and the best approach to integrate the different variables into a simplified damage-resistance assessment has not been well studied. Furthermore, the relationships of the damage traits to sugar production have not been comparatively assessed.  We planted a replicated, two-location test of 28 clones typical of the selection stage screened  for borer resistance in the Louisiana sugarcane breeding programs. We recorded the five  measures together with sucrose production and its components. Using appropriate variance components, the heritability, expected response to selection, and genetic correlations among the traits were used to construct selection indices of all combinations of the five damage traits studied. We used the regression coefficients of the damage traits on sucrose production as economic weights. The indices indicated that percent bored internodes was the most effective single trait to reduce sugarcane borer damage. If data collection costs were considered, then the subjectively assessed damage rating was the most expeditious of the traits examined. High correlation values among several of the traits lead to the observation that inclusion of more than the bored internode, exited internodes and the damage rating in an index were unnecessary.