Abstract

DE SOUSA-VIEIRA, Orlando; REA, Ramón  and  BRICENO, Rosaura. The use of clonal repeatibility to select environments for sugarcane regional trials in Lara and Yaracuy States. Bioagro [online]. 2003, vol.15, n.2, pp.77-82. ISSN 1316-3361.

The term "clonal repeatability" refers to the phenotypic correlation between different plants of the same clone. The technique is quite useful to look at the effectiveness of sugarcane (Saccharum sp., hybrid) selection and to estimate genotype by environment interaction. The present study was carried out to identify similar outfield test sites in order to explore different ways to optimize testing efficiency. Cane yield (TCH) and percentages of pol in cane (Pol % cane) were used as variables. Results indicated that all four sites should be kept as outfield test sites. This holds true for the sites but not for the harvest seasons. Early harvest was the season most affected by genotype by environment interaction, which reduces the effectiveness of clone selection. Results of repeatability between harvest seasons within testing sites suggested that sugarcane clone selection in Veroes and Río Turbio would be equally effective using just the early harvest season. In contrast, the test sites Matilde and El Rodeo should maintain both harvest seasons. Wide sense heredability results were in agreement with those obtained using repeatability analysis, which showed Matilde and El Rodeo as the testing sites with the higher variability due to environmental factors.

Keywords : Saccharum sp.; heredability; genotype x environment interaction.