INTRODUCTION
Flax cultivars with light colored seeds have been reported to have lower germination, less vigor, and lower field emergence than cultivars with dark colored seed (1, 2, 3, 6, 7, 8). Some of these observations have also been made at the NDSU Langdon Research Extension Center (Halley and Lukach, personal observations). Beneficial effects of the use of fungicide treatments on flax seed such as greater germination and field emergence have been reported (4, 5, 6). Although registered fungicide seed treatments for use on flax in North Dakota are available, little information has been available on their efficacy in a North Dakota environment. The objective of this project is to evaluate four fungicide seed treatments and an untreated control on yellow and brown seed type flax cultivars.
METHODS
Field research was conducted at the NDSU Research Extension Centers located in Langdon and Carrington, ND. The seed treatment fungicides Captan, Thiram, Dithane, and Maxim were applied to seeds of flax cultivars Omega (yellow seed) and York (brown seed) as slurries in early Spring 2003. Plots were planted 28 Apr 2003, 16 May 2003, 2 May 2004, 10 May 2004 at Langdon and Carrington, respectively. Plant stand was measured by counting the number of plants in 3 ft section of row in each plot. Roots from 5 flax plants were collected from each plot. Roots were washed and evaluated for disease using a 0 to 4 rating scale. A disease severity index (DSI) was calculated for each plot by: (mean severity X incidence %) / 4. Lesioned roots were surface-sterilized with a 10% Clorox solution for 1 min., rinsed with sterilized distilled water, and placed on potato dextrose agar for isolation of pathogens. Plots were harvested and yield was determined. Plots were organized in a randomized complete block design with 6 replications at Langdon and 4 replications at Carrington. Data were statistically analyzed using the general linear model procedure (PROC GLM) in SAS (SAS Institute, Inc., Cary, NC).
RESULTS AND DISCUSSION
Langdon 2003. There were no significant (P ≤ 0.05) cultivar by seed treatment interactions; therefore, main effects only are presented. There were significant differences between cultivars for disease severity index (DSI), test weight, and yield (Table 1). There was not a significant difference between cultivars for plant stand. There were no significant differences among fungicide seed treatments for any of the measured parameters (Table 2).
Langdon 2004. There were no significant (P ≤ 0.05) cultivar by seed treatment interactions; therefore, main effects only are presented. There were no significant differences between cultivars for any of the measured parameters (Table 3). Significant differences among seed treatments occurred for disease incidence, disease severity, and DSI, but not for stand or yield (Table 4). Plots planted with Dithane treated seed had significantly less disease incidence than plots treated with untreated seed. Plots planted with seed treated with any of the fungicides had significantly lower disease severity and DSI than the untreated control.
Carrington 2003. There were no significant (P ≤ 0.05) cultivar by seed treatment interactions; therefore, main effects only are presented. There were significant differences between cultivars for DSI and oil concentration (Table 5). No significant differences between cultivars were detected for plant stand, test weight, or yield. There were no significant differences among fungicide seed treatments for any of the measured parameters (Table 6).
Carrington 2004. No significant (P ≤ 0.05) cultivar by seed treatment interactions was detected; therefore, main effects only are presented. Significant differences were detected between cultivars for yield, but not for any of the other measured parameters (Table 7). Cultivar Omega had significantly greater yield than cv. York. No significant differences were detected among seed treatments for any of the measured parameters.
In general, fungicide seed treatments did not provide many benefits over the untreated control. Although root disease was reduced by fungicide seed treatments at Langdon in 2004, yield benefits were not observed. The cultivar York tended to perform slightly better at Langdon; however at Carrington, the two cultivars performed very similar. In general, no effects of seed color or fungicide seed treatments were observed in this study that is cause for making any new flax production recommendations.
LITERATURE CITED
1. Comstock, V. E., Ford, J. H., and Beard, B. H. 1963. Association among seed and agronomic characteristics in isogenic lines of flax. Crop Sci. 3:171-172.
2. Culbertson, J. O. and Kommedahl, T. 1956. The effect of seed coat color upon agronomic and chemical characters and seed injury in flax. Agron. J. 48:25-28.
3. Culbertson, J. O., Comstock, V. E., and Frederiksen, R. A. 1960. Further studies on the effect of seed coat color on agronomic and chemical characters and seed injury in flax. Agron. J. 52:210-212.
4. Mercer, P. C., McGimpsey, H. C., and Ruddock, A. 1988. The control of seed-borne pathogens of linseed by seed treatments. Tests Agrochem. Cult. 9:30-31.
5. Mercer, P. C., McGimpsey, H. C., and Ruddock, A. 1989. Effect of seed treatment and sprays on the field performance of linseed. Tests Agrochem. Cult. 10:50-51.
6. Reitz, L. P., Hansing, E. D., Davidson, F. E., and Decker, A. E. 1947. Viability and seed treatment of flax. J. Am. Soc. Agron. 39:959-970.
7. Saeidi, G. and Rowland, G. G. 1999. The effect of temperature, seed colour and linolenic acid concentration on germination and seed vigour in flax. Can. J. Plant Sci. 79:315-319.
8. Saeidi, G. and Rowland, G. G. 1999. Seed colour and linolenic acid effects on agronomic traits in flax. Can. J. Plant Sci. 79:521-526.
