-year multistate comparison of supercore accessions was conducted in five states in northern temperate latitudes. Data were collected on survival, cold tolerance, disease susceptibility, runner production, flowering and fruiting dates, and fruit size and quality in
For years, strawberry ( Fragaria × ananassa L.) runner plant nurseries have relied on methyl bromide (MB) or mixtures of MB and chloropicrin (Pic) fumigation of soil to produce healthy transplants ( Ajwa et al., 2003 ; Kabir et al., 2005
System requirements for organic strawberry (Fragaria × ananassa) runner production under cover were determined during the 2001-02 and 2002-03 seasons. In the field, yield and fruit quality were assessed for organically produced runners (plug and bare-rooted transplant) in comparison with barerooted conventionally produced runners under organic, BioGro certified production conditions. The preferred organic production system was the enhanced suspended system, where mother plants grew on benches in the tunnel house and the first two runners were potted into growth substrate. This system produced approximately 50 plug transplants/mother plant or 200 plug transplants/m2. The least preferred system was the nursery bed, where mother plants were allowed to produce runners that yielded approximately 100 bare-rooted runners or 100 transplants/m2. Tunnel house production of runners (plug transplants and bare-rooted) allowed earlier planting (March vs. May) compared to field-produced bare-rooted runner plants. The earlier planting date increased yield by approximately 181 g/plant. Under organic production conditions, organically produced runners (plug and bare-rooted transplants) performed at least as well as bare-rooted conventionally produced runners. Our results show that indoor production of organic strawberry runners is possible. We also showed that organically produced runners (bare-rooted and plug transplants) perform similarly in the field compared to bare-rooted conventionally produced runners. Generally, there were no differences in yield or fruit quality among runner sources.
.2 billion, accounting for 79% of the total U.S. gross sales ( National Agricultural Statistics Service, 2007 ). California nurseries produce more than a billion strawberry runner plants annually with a total value of ≈$60 million ( California Strawberry
The National Plant Germplasm Repository, Corvallis, houses over 700 different Fragaria genotypes. Many of these produce few or no runners, making propagation difficult by in vitro or conventional methods. Experiments were run to determine the response of non-runnering genotypes to environmental conditions and GA3 treatments. Two groups of plants of 12 genotypes were grown in a 25°C growth chamber (GC) with 24 h light. One group was sprayed twice with 500 ppm GA3, 24 h apart, while a second group was not sprayed. Control plants of each genotype were grown at ambient temperature and long days and were not sprayed with GA3. Both F. vesca L. cultivars and day-neutral genotypes produced significantly more runners with the GA3 GC treatment than the unsprayed GC or the control. Most June-bearing cultivars had improved runnering with both GC treatments. A separate experiment using 30 genotypes with two GA3 sprays (500 ppm, 24 h apart) at ambient temperature and long daylength showed that plants with the GA3 sprays produced significantly more runners than unsprayed controls. In both experiments, GA3 sprays improved runner production by most of the unresponsive Fragaria genotypes.
Strawberry genotypes (Fragaria × ananassa Duchesne) varying in yield per plant were studied. In 1985, genotypes were grown in matted rows and in 1986 as individual plants. Yield per plant within genotypes was mainly dependent on the number of berries per plant, regardless of cultural system. Other variables were correlated with yield, including crown dry weight and leaf area after harvest, and number of inflorescences, which indirectly affected berry number. Potential differences in yield within genotypes apparently were established prior to flower bud differentiation. Variables associated with yield among genotypes differed with cultural conditions. When genotypes were grown in matted rows, vegetative variables were highly correlated with yield. With less interplant competition, reproductive variables were correlated with yield among genotypes. Data suggested that, in some genotypes, runnering and fruiting may have competed for assimilates. Genotypic variability in yield components suggests that genotypes with similar yield can have different routes to yield.
Using the annual hill cultural system, runners of 2 strawberry cultivars were removed twice monthly, monthly, or left on the plants during each of 2 seasons. An additional treatment was the transplanting of runners into the planting slits of the original transplants followed by removal of the original transplants when the runners became established. ‘Tufts’ produced 2 to 8 times more runners than ‘Dover’, over a 2 to 3 month period instead of one month as with ‘Dover’. Early marketable yields of ‘Tufts’ were reduced each season when runners remained attached to the fruiting plants, and the total marketable yield was reduced for the 2nd season as well. Yields were reduced because of fewer marketable-size fruit. ‘Dover’ yields were unaffected by runner removal treatments. Early and total marketable fruit yields of the runner plants of both cultivars were reduced each season compared to other treatments. Early yields of ‘Dover’ were greater than those of ‘Tufts’.
Three preplant soil fumigation treatments were applied on 5 Apr. 1993 to a nursery site that had not been planted previously to strawberries (Fragaria ×ananassa Duch.): 1) a mixture of 67 methyl bromide: 33 chloropicrin (CP) (by weight, 392 kg·ha–1) (MBCP); 2) 140 kg CP/ha; and 3) nonfumigation (NF). On 26 Apr., cold-stored `Chandler' and `Selva' strawberry plants of registered stock were established in each treatment. Soil and root/crown disease symptoms were absent in all treatments during the course of the study. In October, runner plants were machine-harvested and graded to commercial standards. The cultivars produced a similar number of runners per mother plant. Fumigation with MBCP, CP, and NF resulted in 18.56, 15.75, and 7.89 runners per mother plant, respectively. For `Selva', runner root and crown dry weights were similar for the MBCP and CP treatments, but NF resulted in significant reductions compared to the other two treatments. For `Chandler', fumigation with CP resulted in reduced root dry weight, and NF resulted in reduced crown and root dry weights compared to fumigation with MBCP. The results demonstrate the marked decreases in strawberry runner production and runner size that can occur in the absence of preplant soil fumigation, even on new strawberry ground. Also, small, but significant, reductions in runner production and runner size may occur with CP applied at a rate of 140 kg·ha–1 compared to standard fumigation with MBCP. Chemical name used: trichloronitromethane (chloropicrin).
In greenhouse and field studies, benzyladenine (BA) and gibberellic acid (GA3) applied together as a foliar spray increased runner production in dayneutral strawberries (Fragaria ×ananassa Duch.) but not when applied separately. Runner production increased linearly with increased BA concentration to 1800 mg·L–1. At high dosages, GA3-treated plants produced elongated internodes that, in the field, led to fewer daughter plants. In Florida, daughter plants derived from plants sprayed with the growth regulators increased yield by up to 10% in fruiting experiments. To induce runnering in the field and greenhouse, a treatment with BA at 1200 mg·L–1 and GA3 at 300 mg·L–1 is recommended. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine (benzyladenine); gibberellic acid A3; gibberellic acids A4 and A7.
Methods were developed for efficient shoot regeneration from leaf and runner tissues of the strawberry (Fragaria × ananassa) cultivars Allstar and Honeoye. Optimal regeneration conditions differed for ‘Allstar’, depending on whether leaf tissue was derived from plantlets grown in vitro or from plants grown in the greenhouse. ‘Allstar’ leaf tissues derived from in vitro cultures regenerated shoots most efficiently in a Linsmaier–Skoog (LS) medium containing 2.5 mg BA and 0.5 mg IBA/liter. ‘Allstar’ leaf tissues derived from greenhouse plants regenerated shoots best in LS medium containing 3.0 mg BA and 0.1 mg IBA/liter. Addition of casein hydrolysate (CH) at either 400 or 600 mg·liter−1 stimulated shoot production. A supplement of KNO3 at 2000 mg·liter−1 also enhanced regeneration efficiency of greenhouse-grown leaf tissues. ‘Honeoye’ had lower regeneration potential in most treatments than ‘Allstar’ and only produced shoots in a LS medium containing 5.0 mg BA, 0.5 mg IBA, and 400 mg CH/liter. Shoots from runner tissues of both cultivars were best obtained using LS medium containing 10.0 mg BA, 2.0 IAA, and 500 mg CH/liter. Shoot production from runners was dependent on the diameter of the runner, with diameters of <2.0 mm having poor regeneration potential. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 1H-indoIe-3-butyric acid (IBA); and 1H-indole-3-acetic acid (IAA).