A comparative analysis into the genetic bases of morphology in tomato varieties exhibiting elongated fruit shape

Fruit shape is a quantitatively inherited charac- ter. In tomato, two major loci, sun and ovate, control fruit shape index, which is the ratio of fruit height over width. In this study, we measured many additional fruit shape fea- tures in three inter-speciWc F 2 populations using the soft- ware application Tomato Analyzer. These populations were derived from varieties carrying elongated fruit but for which the major shape loci diVered. We compared the eVect of the major fruit shape loci with overall shape, as well as with the distal and proximal end shape features in each pop- ulation. sun and ovate represented the largest eVect on fruit shape in the Howard German and Sausage F2 populations, respectively. The largest eVect QTL in the Rio Grande pop- ulation carrying neither sun nor ovate, were fs8.1 on chro- mosome 8 and tri2.1/dblk2.1 on chromosome 2. These latter loci were also segregating in the other two popula- tions, thus indicating common regions that control shape across the three populations. The phenotypic analyses showed that sun and ovate contributed to almost all aspects of shape such as the distal and proximal end features. In Rio Grande however, the largest eVect QTL did not control all aspects of shape and the distal and proximal features were distinctly controlled in that population. Combined, our results implied that within the cultivated tomato germ- plasm pool the largest eVect on elongated fruit shape was controlled by a combination of the loci sun, ovate, fs8.1 and