Vol. 10, Issue 9 (2021)

Author(s):
A Samal, S Mohanty, S Das, BC Das and JK Beura

Abstract:
An investigation was undertaken to study the effect of polymer coating of cowpea seeds in improving its storability and performance. Freshly harvested seed of cowpea cv. Utkal Manika (Rabi 2018-19 produced seed) was taken and assessment of germinability and vigour was done prior to polymer coating of the seeds. The experiment was laid out in RBD with three replications and twelve treatments, viz., uncoated seeds stored in cloth bags (Control), uncoated seeds stored in 700 gauge polythene bags, and polymer seed coatings with Methyl cellulose, Ethyl cellulose, Polyvinyl pyrrolidone, Hydroxy propyl cellulose and Methyl vinyl acetate, each at 3 ml and 4 ml per kg seeds. Seeds were then dried to original moisture content and stored under ambient conditions from June 2019 to December 2019 in cloth bags, except T₂, which was stored in 700 gauge polythene bags. Observations on various seed physiological quality and seed health parameters were recorded at monthly intervals. After six months of storage, the seeds were used to study their field performance. Results revealed that there was gradual increase in moisture content over six months of storage under ambient condition in cloth bags, the increase being relatively higher in the uncoated seeds (Control), compared to all the coating treatments. Seed germination and vigour declined progressively over the period of storage, the rate of decline being faster in the uncoated Control, as compared to the uncoated seeds stored in 700 gauge polythene bags, as well as all polymer coating treatments. Seeds coated with Methyl cellulose @ 4 ml/kg seed recorded significantly higher seed germination (80.50%), while lowest germination was recorded in uncoated Control (72.00%) after six months of storage. Similar trend was observed with regards to the field emergence. Seed infection and infestation were highest in Control compared to seed coating with polymers, with Polyvinyl pyrollidone and Methyl vinyl acetate each at 4 ml/kg seeds proving to be the best. With regards to field performance, plant height, number of branches per plant, pod length, number of pods per plant, number of seeds per pod, seed yield and 100-seed weight were highest from coating with Polyvinyl pyrrolidone @ 4 ml/kg seeds, followed by Methyl cellulose @ 4 ml/kg seeds. Highest seed yield of 22.59 q/ha was obtained from Polyvinyl pyrrolidone @ 4 ml/kg seeds (25.99% higher over Control), followed by Methyl cellulose @ 4 ml/kg seeds (22.52 q/ha). The uncoated seeds (Control) in cloth bag recorded least seed yield per hectare (17.93 q/ha). The polymer seed coatings did not have any significant influence on the quality of seed produced, viz., seed germination and vigour indices, or on the seed carbohydrate and protein contents. Thus, polymer seed coating with Polyvinyl pyrrolidone @ 4 ml/kg seeds or Methyl cellulose @ 4 ml/kg seeds played important role in maintaining seed quality during storage, which was manifested in improved plant growth, seed yield attributing parameters and seed yield of cowpea.