Genotype x Environment Interaction in Vitis rotundifolia Michaux

¹ Center for Viticultural Sciences, Florida Agricultural and Mechanical University, Tallahassee, FL 32307
² Central Florida Agricultural Research and Educational Center, IFAS, University of Florida, Leesburg, FL 32749.

Six muscadine grape cultivars were evaluated in two locations in Tallahassee, Florida (Campus Vineyard and West Farm Vineyard), for in situ °Brix and pruning weights. Overall performance of all cultivars for the two traits was better on the Campus Vineyard when compared to the West Farm Vineyard. The genotype x environment effects from combined analysis of variance were significant for the two traits. This resulted in changes in cultivar rankings between both locations. Ecovalence analysis revealed that the cultivar Fry had a wide ecological adaptation for relatively high in situ °Brix production, while Cowart, although stable over all locations, consistently showed low performance for pruning weights and in situ °Brix. Welder, on the other hand, had high ecovalence for in situ °Brix and moderate ecological adaptation for pruning weights. Dixie showed the least ecovalence for °Brix content but only moderate adaptability for pruning weights. The two cultivars showing the least ecological adaptation for pruning weights were Higgins and Noble. Although some cultivars may be recommended for cultivation over a wide range of environments, it may be necessary to specify particular environments for other cultivars. Furthermore, breeding lines should be tested over a broad range of environments prior to being released.

Key words: ecovalence, in situ °Brix, muscadine grapes, pruning

Submitted on July 14, 1987