The status of Pseudomonas syringae pv. actinidiae (Psa) in the New Zealand kiwifruit breeding programme in relation to ploidy level
The bacterium Pseudomonas syringae pv. actinidiae (Psa) causes a disease of kiwifruit vines that was first detected in New Zealand in November 2010 in an orchard in the Bay of Plenty. Since then, the disease has spread quickly to other orchards, including the Plant & Food Research (PFR) orchards in Te Puke and Kerikeri. The PFR breeding programme is one of the largest kiwifruit breeding programmes in the world, with more than 100,000 seedlings being evaluated each year. Since the arrival of Psa in PFR orchards, regular field monitoring and removal of Psa-infected seedlings have been carried out to manage the disease and to identify Psa-resistant genotypes. To date, a total of 57,000 vines has been removed because of Psa symptoms. At both Kerikeri and Te Puke during the first year after planting, more than 60% of diploid and around 50% of tetraploid seedlings of Actinidia chinensis var. chinensis were affected. Among hexaploid A. chinensis var. deliciosa seedlings, there were lower removal rates, of 3 and 8% for Kerikeri and Te Puke, respectively.
Saei, A., Hoeata, K., Krebs, A., Sutton, P., Herrick, J., Wood, M. and Gea, L. (2018). The status of Pseudomonas syringae pv. actinidiae (Psa) in the New Zealand kiwifruit breeding programme in relation to ploidy level. Acta Hortic. 1218, 293-298
Actinidia chinensis var. chinensis, Actinidia chinensis var. deliciosa, kiwifruit breeding, Psa impact, Psa resistance