2020 Volume 62 Issue 1 Pages 2-11
As cultivated tomatoes are autogamous (self-fertilizing) plants, we had cultivated commercial cherry tomato F1 cultivars ‘Orenji Kyaroru (Sakata Seed Co.), Aiko (Sakata Seed Co.) and Tyinkar Beru (Nanto Seed Co.)’ then got self-pollinated F2 seeds from the harvested fruits. We have cultivated 104, 70 and 41 F2 generation individuals respectively with 10.5 cm diameter small pots. In these F2 individuals, we observed clear genetically segregated characters of leaf colors with growth degree, flesh colors, pericarp colors. Especially in the case of ‘Orenji Kyaroru F2’, it showed three Mendel’s laws, i.e. the law of dominance, segregation and independence. We conclude that commercial cherry tomato F1 cultivars are good teaching materials for genetics because you cultivate them and can easily get F2 seeds which enable to cultivate sufficient quantity of individuals to observe genetic phenomena. In scientific course of a high school, they cultivated ‘Orenji Kyaroru F2’ and successfully observed genetic segregations. A survey by questionnaire showed that they have become more interested in genetics and understood Mendel’s laws more deeply. It is an advantage to use commercial cherry tomato F1 cultivars because you don’t need to cross or hybridize which is somewhat complicated procedure. Another advantage is that we can observe genetic segregation of leaf colors easily within two or three weeks after sowing. At the same time, it is a great disadvantage that we cannot use the parents of the F1 cultivars because they are never allowed to be taken out from the seed companies.
