INFLUENCE OF HALOGEN TREATMENTS ON VIABILITY OF AGED COTTON SEEDS

摘要

Seeds of seven Gossypium hirsutum genotypes, stored under ambient condition for one, two, three and four years were treated with chlorine (5g kg~(-1)) and iodine (3g kg~(-1)) halogen formulations. The treated seeds were accelerated aged at 40°C and 95% RH for 48 hrs. The estimations of seed quality and predictions of seed storability revealed that seeds treated with chlorine (@ 5g kg~(-1)) and iodine (@ 3g kg~(-1)) formulation extended the viability and vigour potential and reduced the pathogenic seed infection. The improvement in viability was 6.0 and 7.0%, respectively due to chlorine and iodine treatments over untreated seeds. The rate of improvement in viability decreased with increasing age of seeds at the time of seed treatment. The mean vigour index over genotypes and seed treatments was 36, 540, 1283 and 1560, respectively in one to four years aged seeds. In all the seed lots, improvements of vigour due to chlorine and iodine treatments were on par with a significant superiority over control. The electrical conductivity and leaching of sugars were noticed less in seeds treated with chlorine and iodine. The dehydrogenase enzyme activity was 2.64,2.26, 2.01 and 1.54, respectively from one to four years aged seeds. This was found to increasedue to iodine (2.20) and chlorine (2.16) treatment than in the untreated seeds (1.98). There were significant reductions in percentage of infected seed, due to chlorine (31.4%) and iodine (30.7%) treatments than in the untreated (44.4). Since, halogen formulations have multi benefits such as improvement in viability and vigour, prevention of pathogenic seed infection and further extension of seed storability, treatment of cotton seeds using the vapour form of chlorine and iodine may be recommended.