Analysis of Genotype and Genotype By Environment Interaction in Louisiana Sugarcane Research Plots By GGE Biplots.

Sugarcane is cultivated under a wide range of soil types and cultural management practices in south Louisiana. The variety development program places experimental varieties in cooperator’s fields across the sugarcane growing region to take advantage of this variability in the selection process. The cooperators apply the same production management practices to the field trials as their commercial fields.  The variety development team then selects and harvests the trials to obtain yield data. The yield and selection of these varieties is affected by genotypic and genotype by environmental (GGE) interactions. To study these effects the sugar per hectare yield data of eleven check varieties sampled over four years including 2-4 crops across 21 locations, was analyzed by GGE biplot software in order to visualize GGE effects.  The resulting analyses suggest yield variability is strongly dependent on crop, year, and variety. There does not appear to be any regional or soil patterns. However, there were significant differences among locations for yield discrimination, and yield stability significantly varied by genotype in the outfield trials. In the nurseries some crop years were more representative of the mega environment than others. The results indicate that each crop year has unique growth conditions that affect both yield and the selection process.