The fertility of transgenic apple carrying exogenous cowpea trypsin inhibitor gene

The Cowpea Trypsin Inhibitor (CpTI) gene was transferred into an apple cultivar of Malus domestica cv. Gala via Agrobacterium-media transformation method in 1998. The transgenic lines confirmed by Southern blot were transferred into the greenhouse. The plants started to flower in 2004. The fertility of the flowers was evaluated in 2004 and 2005. The results showed that the pollen germination rate of the transgenic plants of Gala varied from 38.1% to 56.3% depending on the transgenic lines, and no significant difference was found between the transgenic and the non-transgenic Gala. The fruit set rate of the transgenic Gala apple varied from 64.9 to 79.7% when the pollen collected from the non-transgenic Fuji apple plants were used for the cross. The fruit set rate of the non-transgenic Fuji apple varied from 47.9 to 69.0% when the pollen collected from the transgenic plants were used for the cross. No significant difference was found between transgenic and non-transgenic crossing combinations. Therefore, it could be concluded that the transgenic Gala apple carrying exogenous CpTI gene was as fertile as non-transgenic plants in terms of the pollen germination and fruit set ability.