Irrigation and cultivar effect on flax fiber and seed yield in the Southeast USA

• Irrigation does not appear to be needed for winter-grown flax for fiber in the Southeast USA.
• Little difference occurred among four European fiber-type cultivars for fiber or seed yield.
• Seed-type flax cultivars with high straw yields may be suitable for fiber production.

Flax (Linum usitatissimum L.) is a potential winter crop for the Southeast USA that can be grown for both seed and fiber. The objective of this research was to evaluate the effect of irrigation on flax straw, fiber, and seed yield of fiber-type and seed-type cultivars at different flax growth stages. The study was conducted during the winter growing seasons of 2010/2011, 2011/2012, and 2012/2013 near Florence, SC. Four fiber-type cultivars and one seed-type cultivar were grown with and without irrigation for two years. The four fiber-types were evaluated for straw and fiber yield in the third year. Soil water was monitored to trigger irrigations. Irrigation was applied before all four harvests in 2010/2011, before only the last harvest in 2011/2012, and was not applied in 2012/2013. Straw harvests were made at the onset of flowering, 10 days past the onset of flowering, 20 days past the onset of flowering, and when seeds were mature. Seed harvests were made at the end of the 2011/2012 and 2012/2013 growing seasons. In 2010/2011, plots had to be replanted in February so crop development was delayed. Irrigation increased straw yield at the last three harvests in that year. In the other two years, when planting occurred at normal times in the fall, irrigation did not influence straw or fiber yield. Irrigation had no significant effect on seed yield. The fiber-type cultivars did not differ for straw or fiber yield. At the onset of flowering harvest, the seed-type cultivar had similar fiber content to the fiber-type cultivars. The fiber-type cultivars had higher fiber content in later harvests. The results support previous research in that fiber-type cultivars appear viable for production as fiber winter crops in the region. The results also suggest that high straw yielding seed-type cultivars could be used, especially in systems with early straw harvests.