Alternative Approaches to Cotton Seed Germination Under Low Moisture Conditions

A comparative evaluation of decorticated cotton seed germination and early rooting under limited moisture conditions in a laboratory setting was conducted in order to better understand options for West Texas cotton planting under drip irrigation.  Standard and decorticated cotton seeds were treated, germinated, grown and periodically X-ray imaged.  Seedling shoot and root measurements were extracted from the X-ray images.  Germination, vigor and development were determined for each treatment.

The seed coat of cotton, while providing beneficial protection from biotic and physical injury and controlling internal water distribution to the embryo also delays the imbibition of soil moisture. This delay necessitates that cotton be planted into moist soil at a depth sufficient for radicle emergence prior to seed desiccation. When humidity and wind speed rapidly dry exposed moist soil, seed depths of 1.5 to 2 inches are required to insure germination, a depth that can result in seedling disease and seed death when soils are cold or salty. To expedite the imbibition of cottonseed and potentially allow shallow planting under dry soil conditions, seed coats have been mechanically removed resulting in dehulled or decorticated seed.

Two treatments were evaluated.  The first was a plant protection combination of Apron XL 3LS (fungicide), Maxim 4FS (fungicide), Systhane 40WP (fungicide), Dynasty CST (fungicide), Avicta Duo (insecticide) and Cruiser (insecticide) and was used on standard, decorticated and “pseudo-hull” seeds.  (The “pseudo-hull” is a polymer coating meant to protect decorticated seeds and prevent premature leaf unfurling below ground.)  The second, a seed primer (rooting enhancer) developed for use with pulses, was used on standard cotton seeds only.  These two treatments were compared to untreated standard, decorticated and “pseudo-hull” seeds.  Thirty-two seeds were evaluated for each treatment/ seed type.