Abstract
Two studies were conducted in 1995 and 1996 in the field and under controlled environments to test the yield and dry matter (DM) content stability of selected sweetpotato genotypes. In the field study, initial screenings of over 300 genotypes were conducted. Six genotypes were selected and further tested under a controlled environment for their adaptability in the Tuskegee University Nutrient Film Technique system for inclusion in crop production for long-duration space missions. In both studies, plants were grown for 120 days. Data collected over the twoyear period were combined and comparisons of genotype performance were done between the two growing conditions. Regression analysis on overall mean for the two environments showed that yield for the six selected genotypes were highest when plants were grown under field conditions. For all six genotypes, there were differences shown in yield performance when they were grown in the greenhouse or under the controlled environment. There was a significant interaction between environment and genotypes for root yield while DM accumulation was independent of environment. Yield stability analysis indicated that lower-yielding genotypes regress closer to unity than higher-yielding genotypes, while variance due to deviations from regression was closest to zero for genotypes whose mean yields were closest to the grand mean.
