|Baldwin, Elizabeth - Liz|
Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/11/2005
Publication Date: 1/1/2006
Citation: Georgelis, N., Scott, J.W., Baldwin, E.A. 2006. Inheritance of high sugars from tomato accession PI270248 and environmental variation between seasons. Journal of the American Society for Horticultural Science. 131(1):41-45. Interpretive Summary: Consumers prefer sweeter tomatoes, thus breeding programs aim to increase sugar levels in tomato breeding lines. In this study a high sugar small-fruited cherry tomato was crossed to a large-fruited tomato that had normal to low fruit sugars and the subsequent generation back-crossed to the respective parents over several seasons (spring and fall in Florida) to study sugar inheritance patterns as affected by environmental conditions. It was found that the sugar level is controlled by more than one gene, and that levels were affected by season perhaps due to the higher amount of solar radiation in spring, resulting in higher sugar levels, than in fall.
Technical Abstract: Small-fruited cherry tomato accession PI 270248 (L. esculentum var. cerasiforme) with high fruit sugars was crossed to large-fruited inbred line Fla.7833-1-1-1 (7833) that had normal (low) fruit sugars. The F1 was crossed to PI 270248 and 7833 to obtain BC1 and BC2, respectively, and self-pollinated to obtain F2 seed. The resulting population was used to study the inheritance of high sugars from PI 270248. Continuous sugar level frequency distributions of BC1, BC2 and F2 suggest that the trait is under polygenic control. Additive variation was significant, but dominance variation was not. There was a heterozygote x heterozygote type of epistasis present that likely caused the F1 sugar level to skew nearly to the level of the high sugar parent. The F2 mean sugar level was lower than the midparent level. Broad sense heritability was 0.86. There was a significant line x season (fall, spring) interaction where lines with higher sugars were affected more by seasons than lines with lower sugars. Sugar level, in general, was higher in spring. Higher solar radiation in spring than in fall may explain the sugar level difference between the seasons.