The wine grape industry in the Okanagan Valley of British Columbia (BC), Canada has grown rapidly with respect to acreage and economic value since the early 1990s, with approximately 4,000 ha of
Previous research utilizing field microplots in Oregon (Pinkerton et al., 2004, 2005; Schreiner, Pinkerton and Zasada, 2012; Schreiner, Zasada and Pinkerton 2012) and California (McKenry et al., 2001) demonstrated that
Given the differences in growing conditions between BC and coastal Oregon and California, and the potential for geographical differences in
In spring of 2007, 160 field microplots were installed at the Agriculture and Agri-food Canada, Summerland Research and Development Centre (SuRDC) (49°33′45.200″ N; 119°38′55.300″ W). Soil at the site was an Osoyoos loamy sand (Wittneben, 1986). Four 40-m long trenches were dug to a depth of 60 cm, with a between-trench spacing of 3 m. Forty 100 L volume ‘Grip-Lip 10,000’ pots (Nursery Supplies, Inc., Chambersburg, PA) were installed in each trench with a 1 m spacing between the center of each pot. On 17 April 2007, all pots were back-filled with excavated soil to an effective soil volume of 92 L, and the granular fumigant Basamid (active ingredient Dazomet, methyl iso-thionate; Engage Agro Corporation, Guelph, ON, Canada) was incorporated into the soil during backfilling at a rate of 16 g/ microplot or 175 g/m3 soil. Immediately after backfilling and adding the Basamid, each pot was wetted to saturation and covered with polyethylene film. At four weeks after fumigation (mid-May 2007), the polyethylene film was removed from all microplots and they were allowed to off-gas until nematode inoculation and planting on July 4, 2007. An Environment and Climate Change Canada climate station was located approximately 500 m from the experimental site. Maximum, minimum, and mean daily temperatures for the warmest (July or August) and coldest (December or January) months at the site during the course of the experiment are summarized in Table 1.
Maximum, minimum, and mean daily temperatures for the warmest (July or August) and coldest (December or January) months at the site during the course of the microplot experiment.
Month, year | Maximum | Minimum | Mean |
---|---|---|---|
July, 2007 | 30.5 | 16.5 | 23.5 |
January, 2008 | 0.3 | −6.6 | −3.2 |
July, 2008 | 29.2 | 14.6 | 21.9 |
December, 2008 | −2.2 | −8.5 | −5.4 |
July, 2009 | 31.1 | 15.5 | 23.3 |
December, 2009 | −1.3 | −6.5 | −3.9 |
July, 2010 | 29.5 | 14.3 | 21.9 |
January, 2011 | 2.0 | −4.3 | −1.2 |
August, 2011 | 29.4 | 14.1 | 21.8 |
One-half of the microplots, randomly chosen, were each inoculated with 220
The plant material was derived from tissue culture and obtained from a commercial nursery where it had been grown in plugs (Bevo Farms, Langley, British Columbia). Twenty of the
A single soil sample was taken from each microplot in late October of 2008, 2009, 2010, and 2011. Each sample was comprised of two 2-cm diameter cores taken to a depth of 30 cm and combined. Nematodes were extracted from a 100 cm3 subsample from each sample using wet-sieving sucrose-centrifugation extraction. The
In 2010, the soil samples were passed through a 6 mm sieve prior to nematode extraction to facilitate removal of root fragments. The root fragments were separated into coarse (> 2 mm diameter) and fine (< 2 mm diameter) size classes, dried, weighed, and data expressed relative to dry weight of the soil sample (i.e. g roots/kg dry soil).
In spring of each year, vines were pruned to a single stem that was trained to the top trellis wire at 1.5-m above the ground. The prunings from each vine were collected, dried, and weighed. Vine trunk diameters were measured at 30 cm above the ground in two cardinal directions each winter, and trunk cross-sectional areas (TCSA) were calculated. An unusually early hard freeze occurred in 2009, when temperatures went below −5°C on three successive nights (October, 10, 11, 12). This cold event resulted in the mortality of 44 vines, leaving 116 vines in the experiment through the 2010 and 2011 growing seasons, with 12, 19, 13, and 18 inoculated vines of 44-53, Riparia Gloire, 3309C, and self-rooted vines, respectively, and 11, 16, 12, and 15 non-inoculated vines of 44-53, Riparia Gloire, 3309C and self-rooted vines, respectively. Soil sampling in 2012 revealed
A chi-square test was first used to determine if the fall 2009 to winter 2010 mortality was disproportionately associated with any particular combination of rootstock and
Population densities of
Effects of rootstock on population densities of
Mx population density | 2011 trunk cross-sectional area (mm2) | 2008-2011 cumulative pruning weights (g dry weight/vine) | Total root biomass (g/kg dry soil) | Fine root biomass (g/kg dry soil) | |||||
---|---|---|---|---|---|---|---|---|---|
Rootstock | Mx/L soil | −Mx | +Mx | −Mx | +Mx | −Mx | +Mx | −Mx | +Mx |
44-53 | 3,559 | 457 | 445 | 135 | 115 | 1.47 | 1.18 | 1.02 | 0.91 |
Riparia Gloire | 4,968 | 340 | 343 | 164 | 153 | 1.52 | 1.31 | 1.21 | 1.09 |
3309C | 3,985 | 559* | 310 | 149 | 153 | 1.44 | 1.73 | 1.11 | 1.34 |
Self-rooted | 2,172 | 269** | 167 | 116*** | 49 | 1.05* | 0.66 | 0.66*** | 0.38 |
Average | 406* | 316 | 141*** | 118 | 1.37** | 1.22 | 1.00* | 0.93 |
Rootstock genotype had significant main-factor effects on all vine growth parameters. Because inherent differences between rootstocks in overall growth characteristics has been analyzed and discussed extensively elsewhere (e.g. Keller, 2010), and the focus of this paper is the impacts of
Trunk cross-sectional area (TCSA) is a robust measure of cumulative vine growth and vigor. We found that TCSA was affected by
While all three rootstocks were equally good hosts for this BC population of
Our data are limited to vegetative growth parameters, as contamination of control microplots required termination of the experiment before it became possible to collect reliable fruit yield data. Additional research is needed to provide a more detailed indication of the damage potential of
The longer-term impacts of
This study builds on previous studies on fine-textured soils in Oregon (Pinkerton et al., 2004, 2005; Schreiner, Pinkerton and Zasada, 2012; Schreiner, Zasada and Pinkerton, 2012), demonstrating that self-rooted ‘Merlot’ and three commonly used rootstocks are excellent hosts for a BC population of