Hybrid Nursery Production

Improve the efficiency of hybrid Prunus rootstock propagation to allow cost-effective tree production by commercial nurseries.

MP-29 does not grow in diameter well.Recently, the interspecific plum-peach hybrid rootstock ‘MP-29’ was released with resistance to ARR. Due to its interspecific origin, ‘MP-29’ cannot be seed propagated and requires clonal propagation. However, despite adequate rooting and shoot elongation, ‘MP-29’ does not reach stem diameters required for scion grafting rapidly enough to be economically viable for commercial production. This slow growth can introduce up to a year-long delay in the production cycle along with decreased efficiency due to liner mortality. Additional concerns include plagiogravitropic shoots (buds on rooted cuttings running parallel to the ground) instead of having an upright growth (pictured below).

Plagiotropic shoots.The second objective of the project is to work with a nursery to optimize the propagation of ‘MP-29’ at large enough volumes for commercial production. A project protocol will be developed for new, improved ARR/PTSL resistant rootstock production. The ‘MP-29’ propagation protocol will be shared with nurseries that serve peach producers. This will include large tree fruit nurseries, with the largest peach producing nurseries located in Tennessee, Pennsylvania, and California.