Potential for Selection Gains Using Actinidia deliciosa (Kiwifruit) Hermaphrodites

Estimating the response to selection and the realized gain for various traits in an Actinidia deliciosa breeding programme is vital to the programme's success. One challenge in advancing the programme is the dioecious nature of this crop. An approach to this challenge is to use progeny-tested males; however, progeny-testing adds at least five years to the selection cycle. Another tactic to improve realized selection gains is to use hermaphrodites. This allows direct selection of fruit attributes from the pollen-source genotypes without the required timeframe for progeny-testing. A 3x3 hermaphrodite diallel has been evaluated for fruit number, harvest soluble solids, fruit weight and dry matter content, to determine if there was an effect linked to the hermaphrodite trait for the attributes evaluated. Taking into consideration the degree of inbreeding among the parents, there was no statistical significance between the hermaphrodite and female progenies in the traits evaluated. This suggests that breeding using hermaphrodites can be implemented without progeny testing, as phenotypic selection can occur on both ovule and pollen parents.