Cotton Seed Quality and Storage Physiology in Relation to Harvest and Post-harvest Storage Techniques

Cotton seed mainly loses its viability and vigour during harvesting and storage. This study was designed to evaluate the effect of picking time and post-harvest storage techniques on germination and vigour of cotton seed. In the first phase of experiment, initial seed quality (seed moisture content, germination and vigour) was determined at four different picking times i.e. 15 August, 15 September, 15 October and 15 November. In the second phase, seed from different picking (Factor A) was dried to 8% moisture contents and stored for six months by different storage techniques i.e., Ginned cotton seed and Un-Ginned seed cotton (Factor B) in different packaging materials i.e. hermetic and jute bags (Factor C). Maximum moisture (17.36%) was recorded from seed cotton picked on 15th September. September picking gave the best quality seed having maximum thousand seed weight (106.13 g) and germination percentage (67.25%). In storage experiment, highest seed vigour index- I (3256.9) and II (29.43), total soluble sugar contents (2.86 mmol g-1 FW), catalase (2.78 U g-1 FW) and peroxidase (1.72 U g-1 FW) was measured from September picked cotton seed stored in hermetic bags after ginning. Highest malondialdehyde contents (3.01 nmol g-1 FW) were measured in August picked un-ginned seed under conventional storage. Maximum seed germination (65%) and lowest seed deterioration was observed in September picked seed stored in hermetic bags after ginning. In conclusion, cotton seed picked during the month of September after drying (maximum 8%) should be ginned and stored in hermetic bags to retain maximum viability for seasonal storage under ambient conditions.