Comparison of selection for root rot tolerance and machine harvestability

P.P. Moore, W.K. Hoashi-Erhardt
The focus of the Washington State University raspberry breeding program is breeding floricane fruiting raspberry cultivars for the Pacific Northwest that combine machine harvestability with root rot tolerance. This study compared selection for root rot tolerance with adaptation to machine harvesting. In 2007, crosses were made among promising selections with the goal of 140 seedlings for each of 30 crosses. Half of the seedlings from each cross were planted with a cooperating grower in Mount Vernon, WA in 2008. These seedlings were machine harvested in 2010 and 2011 and selections made while machine harvesting the seedlings. The remaining seedlings from these crosses were planted at the Washington State University Goss Farm, Puyallup, WA. The Puyallup Goss Farm is known for having high levels of Phytophthora, and seedlings at this site are subjected to root rot pressure. Seedlings at each location were also evaluated subjectively for yield, ease of harvest, firmness, color and flavor. There were differences in selection rate for the crosses between the two locations. At Mount Vernon, 76 selections were made among 2,160 seedlings (3.5%), where the crosses with the most selections were WSU 1638 × WSU 1447 (15% selected) and WSU 1447 × Chemanius (14% selected). WSU 1447 was a parent of 6 of the 7 “best crosses” and a parent of 52 of the 76 selections. At Puyallup, 31 selections were made among the 2,114 seedlings (1.5%), where the cross with the most selections was WSU 1447 × WSU 0697 (7% selected). Neither WSU 1447 nor WSU 0697 have any obvious root rot tolerant parents. Six of the seven crosses with more than one selection at the Puyallup had 'Cascade Bounty' or WSU 1499 as parents, both known to be root rot tolerant.
Moore, P.P. and Hoashi-Erhardt, W.K. (2020). Comparison of selection for root rot tolerance and machine harvestability. Acta Hortic. 1277, 149-154
DOI: 10.17660/ActaHortic.2020.1277.21
Rubus, Phytophthora, machine harvest, firmness, flavor

Acta Horticulturae