ASHS 2015 Annual Conference

Fruit growers in northern New Mexico are frustrated with erratic and severe late spring frosts. Most growers would like to diversify their operation to other alternative fruit species to reduce the risks. Blackberries bloom later and late frosts present less chance of flower damage, but their winter hardiness and adaption to high pH soils are not clear in northern New Mexico. Two semi-trailing, three free-standing and one primocane blackberry cultivars were tested both in high tunnels and in the field from 2011-14 at New Mexico State University Sustainable Agriculture Sciences Center at Alcalde, NM. Two semi-trailing cultivars-Triple Crown and Chester were planted at 1.5×2.6 m in a 5.2×12.2 m high tunnel with an identical field planting and all free standing cultivars (Ouachita, Natchez and Navajo, and primocane cultivar-Prime–Ark 45) were planted at 0.6×1.7 m in another 5.2×12.2 m high tunnel with an identical field planting. Comparing all cultivars together, yield of floricane cultivars was correlated to winter damage while primocane cultivar Prime-Ark 45 had reliable crops in high tunnel each year in northern New Mexico. Comparing the winter of 2012–13 to 2013–14, 2013–14 was milder with minimal temperature of –15.6 °C and 2012–13 was colder with minimal temperature of –21.6 °C. In 2013, all floricane cultivars lost their crop in the field and had minimal yield in high tunnels. ‘Chester’ was hardier than ‘Triple Crown’ and ‘Ouachita’ was hardier than ‘Natchez’ and ‘Navajo’. When temperature dropped to –21.6 °C, High tunnels could protect the cane from winter damage, but not the flower buds. In 2014, there was light winter damage in the field but a full crop in high tunnels for both semi-trailing and free standing cultivars. ‘Triple Crown’ had higher yield than ‘Chester’ both in the high tunnel (21,800 kg/ha versus 11,239 kg/ha) and in the field (7252 kg/ha versus 3843 kg/ha). ‘Ouachita’ had higher yield than ‘Natchez’ and ‘Navajo’ in both 2013 and 2014. ’Prime-Ark 45’ had similar yield to ‘Ouachita’ in the high tunnel in 2014 but twice the yield of ‘Ouachita’ in 2013. ‘Navajo’ did not grow well either in the field or in the high tunnel, presumably because of high pH soils.  Growers can grow blackberries and expect a good yield in mild winters but floricane blackberries are marginal and winter damage is expected in severe winters; and ‘Prime-Ark 45’ had reliable crops in high tunnels in northern New Mexico.