EXTENSION PLANT PATHOLOGY

Evaluation of fungicide seed treatments on flax cultivars differing in seed color

Carl A. Bradley, Dept. of Plant Pathology, North Dakota State University (NDSU)

Scott Halley, NDSU Langdon Research Extension Center

Robert Henson, NDSU Carrington Research Extension Center

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 (Hally 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 and 16 May 2003 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 on 1 Jul and 9 Jul at Langdon and Carrington, respectively.  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 20 Aug and 15 Sep at Langdon and Carrington, respectively.  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.  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).

     Carrington.  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 3).  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 4).          

     At Langdon, the cultivar York consistently performed better than Omega.  At Carrington, the 2 cultivars did not differ except for disease, in which Omega had a greater DSI than York.  The overall DSI at Langdon was greater than Carrington, which could have had a more adverse effect on its performance at Langdon.  The preliminary data presented herein suggests that Omega may be more susceptible to root diseases than York.  Fungicide seed treatments appeared to have no significant benefit on either cultivar based on 1 year of observation.  Repeating this study in 2004 is necessary to be able to make firm conclusions.

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.  
Table 1. Cultivar effects combined across all seed treatments on stand, root disease, test weight, and yield at Langdon, ND in 2003.

^a DSI, Disease severity index, for root diseases was calculated for each plot by:  (mean disease severity based on a 0 to 4 scale X disease incidence %) / 4.

Table 2. Seed treatment effects combined across all cultivars on stand, root disease, test weight, and yield at Langdon, ND in 2003.

^a DSI, Disease severity index, for root diseases was calculated for each plot by:  (mean disease severity based on a 0 to 4 scale X disease incidence %) / 4.

Table 3. Cultivar effects combined across all seed treatments on stand, root disease, test weight, yield, and oil concentration at Carrington, ND in 2003.

^a DSI, Disease severity index, for root diseases was calculated for each plot by:  (mean disease severity based on a 0 to 4 scale X disease incidence %) / 4.

Table 4. Seed treatment effects combined across all cultivars on stand, root disease, test weight, yield, and oil concentration at Carrington, ND in 2003.

^a DSI, Disease severity index, for root diseases was calculated for each plot by:  (mean disease severity based on a 0 to 4 scale X disease incidence %) / 4.