Increased growth response of strawberry roots to a commercial extract from Durvillaea potatorum and Ascophyllum nodosum

Journal of Applied Phycology, Jan 2018

The withdrawal of soil fumigants like methyl bromide is forcing strawberry growers to consider supplementary and alternative ways of producing crops. In addition to controlling soil-borne pests, soil fumigation causes an increased growth response in strawberry roots, and the use of biostimulants may offer an alternative to replace this response. We tested the hypothesis that treatment with a commercial extract (Seasol®) from the seaweeds Duvillaea potatorum and Ascophyllum nodosum can increase root growth, and transplant (runner) and fruit yields of strawberry. From 2014 to 2016, we conducted three field trials on strawberry farms in the nursery sector at Toolangi and in the fruiting sector at Coldstream in Victoria, Australia. We applied the seaweed extract as a monthly drench (10 L ha−1) to two cultivars of strawberry (‘Albion’ and ‘Fortuna’), compared with an untreated control. In the nursery sector, use of the extract significantly increased the density of secondary roots (feeder roots) on harvested runners by up to 22%. Treatment with the extract also significantly increased yields of marketable runners by 8–19%. In the fruit sector, use of the extract significantly increased the root length density (root length per volume of soil) of strawberry plants by 38% and marketable fruit yields by 8%. Root length density at final harvest and marketable fruit yield of strawberry were highly correlated (r = 0.94). This relationship provides an insight into the mode of action of seaweed extracts and is discussed. Overall, the results show the potential benefits of the integrated use of seaweed extracts in strawberry production across the nursery and fruit sectors, and their promise for supplementing or replacing the increased growth response provided by soil fumigants.

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Increased growth response of strawberry roots to a commercial extract from Durvillaea potatorum and Ascophyllum nodosum

Journal of Applied Phycology https://doi.org/10.1007/s10811 Increased growth response of strawberry roots to a commercial extract from Durvillaea potatorum and Ascophyllum nodosum Scott W. Mattner 0 1 Mirko Milinkovic 0 1 Tony Arioli 0 1 0 Seasol International , Bayswater, VIC 3155 , Australia 1 Victorian Strawberry Industry Certification Authority , Toolangi, VIC 3777 , Australia The withdrawal of soil fumigants like methyl bromide is forcing strawberry growers to consider supplementary and alternative ways of producing crops. In addition to controlling soil-borne pests, soil fumigation causes an increased growth response in strawberry roots, and the use of biostimulants may offer an alternative to replace this response. We tested the hypothesis that treatment with a commercial extract (Seasol®) from the seaweeds Duvillaea potatorum and Ascophyllum nodosum can increase root growth, and transplant (runner) and fruit yields of strawberry. From 2014 to 2016, we conducted three field trials on strawberry farms in the nursery sector at Toolangi and in the fruiting sector at Coldstream in Victoria, Australia. We applied the seaweed extract as a monthly drench (10 L ha−1) to two cultivars of strawberry ('Albion' and 'Fortuna'), compared with an untreated control. In the nursery sector, use of the extract significantly increased the density of secondary roots (feeder roots) on harvested runners by up to 22%. Treatment with the extract also significantly increased yields of marketable runners by 8-19%. In the fruit sector, use of the extract significantly increased the root length density (root length per volume of soil) of strawberry plants by 38% and marketable fruit yields by 8%. Root length density at final harvest and marketable fruit yield of strawberry were highly correlated (r = 0.94). This relationship provides an insight into the mode of action of seaweed extracts and is discussed. Overall, the results show the potential benefits of the integrated use of seaweed extracts in strawberry production across the nursery and fruit sectors, and their promise for supplementing or replacing the increased growth response provided by soil fumigants. Fragaria × ananassa; Root length density; Seasol®; Seaweed extract; Specific root length; Strawberry runner Introduction The Australian strawberry (Fragaria × ananassa) industry was recently valued at AUS$420 million per annum. Production occurs in every Australian state, with major regions in Victoria and Queensland. The fruit sector in Victoria predominantly uses day-neutral cultivars of strawberry (e.g. Albion), which fruit in response to mild temperatures over summer. In contrast, the fruit sector in Queensland predominantly uses short-day cultivars of strawberry (e.g. Fortuna), which fruit in response to short days and mild temperatures through winter. * Pathogen-tested runners (bare-rooted transplants) form the backbone of a profitable strawberry fruit industry. Seventy percent of Australian runners are produced in Victoria, with the remainder mostly produced in Queensland. In the 2014/2015 season, 90 million runners were planted in the fruit sector (Horticulture Innovation Australia 2017) . Strawberry runner and fruit production in Australia and many regions around the world relies on the use of fumigants to control soil-borne pathogens, weeds and other pests (Ajwa et al. 2003; Fennimore et al. 2008; López-Aranda 2014; Mattner et al. 2014) . Soil fumigation can also cause an increased growth response in the roots of strawberry and other crops that is not related to control of soil-borne pathogens and pests (Wilhelm and Paulus 1980; Yuen et al. 1991; Porter et al. 2005) . The increased growth response of crop roots is associated with changes in soil biology and chemistry, particularly nitrogen, following fumigation (Ridge 1976; Rovira 1976; Porter et al. 2005) . Furthermore, Yuen et al. (1991) found that improved root density and health of strawberry plants caused by soi (...truncated)


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Scott W. Mattner, Mirko Milinkovic, Tony Arioli. Increased growth response of strawberry roots to a commercial extract from Durvillaea potatorum and Ascophyllum nodosum, Journal of Applied Phycology, 2018, pp. 1-9, DOI: 10.1007/s10811-017-1387-9