Storage Technologies to Enhance Longevity in Paddy ( Oryza sativa L.) Seed of Parental Lines IR58025A and IR58025B of Hybrid PRH-10

Abstract

Storage conditions, storage containers and seed treatments prior to storage are important factors responsible for retaining seed longevity. But ideal storage environment are seldom available for the precious seed, especially under tropical conditions. Maintenance of seed germination in vulnerable parental lines IR 58025A (6A) and IR 58025B (6B) of paddy ( Oryza sativa L.) during storage was investigated using integration of different treatments as storage containers (jute bags/ polylined jute bags), storage conditions (ambient/LTLH i.e. low temperature, low humidity or controlled) and seed dressings (captan/thiram) at Karnal seed godowns in North India during 2000-2007. Ten kg of seed was stored per treatment. Seed was taken from the fields of Indian Agricultural Research Institute, Regional Station, Karnal (India). The initial moisture content of paddy seeds was kept 13% which is a standard. The results revealed that there was significant difference in the storability of paddy seeds under different storage conditions. Under LTLH storage conditions (temperature:15 °C and relative humidity:30%) paddy seeds maintained germination above the minimum seed certification standards (80%) up to 60 months after seed treatment as against 24 months when stored under ambient conditions. The germination of seeds stored under LTLH conditions (86.1%) and in polylined jute bags (75.3%) was significantly higher than seeds stored under ambient condition (61.9%) and in jute bags (72.8%) after 60 months of seed treatment. Treatment with thiram/captan also showed improved seed germination by 7% as against untreated control. Seed vigour also followed a trend similar to seed germination. The incidence of seed mycoflora was 54.8% and 45.2% in seeds of 6A and 6B, respectively. This was significantly higher in seeds stored under LTLH conditions (62.1%) and in jute bags (39.1%) compared to seeds stored under ambient condition (64.7%) and in polylined jute bags (47%). In all 16 fungi were found associated with paddy seeds. However, the fungal incidence in treated seeds was 29.2% as against 70.8% in untreated control. Seed moisture content did not vary much amongst different treatments though it was higher in seeds stored under ambient storage conditions (11.7%) as against seeds stored under LTLH- low temperature, low humidity conditions (9.2%). Keywords: Paddy-Rice; Seed Germination; Seed Mycoflora; Seed Storage; Storage Condition