1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)

Permanent URI for this communityhttp://localhost:4000/handle/123456789/1

Browse

Filters

20251

Settings

Author: search.filters.author.Deepna, E P.Subject: search.filters.subject.Seed biopriming

Search Results

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Optimization of biopolymers for seed biopriming in rice (Oryza sativa L.)
    (Department of Agricultural Microbiology, College of Agriculture, Vellanikkara, 2025-01-24) Deepna, E P.; Panchami, P S
    Seed biopriming is a novel, cost-effective method that applies beneficial microbial inoculants directly to the seed surface, enhancing seed growth and overall agricultural production. The technique of incorporating biopolymers as a thin, protective film around the seed without altering its size or shape has emerged as a recent trend.These biopolymers help to maintain microbial stability and activity, providing a favorable environment for the inoculants. The present study entitled “Optimization of biopolymers for seed biopriming in rice (Oryza sativa L.)” aimed to develop rice seeds coated with biopolymers and beneficial microbes to enhance growth and yield in rice, as well as to improve seed quality and longevity of bioprimed seeds. The study focused on standardization of the concentrations and imbibition times of biopolymers and bioagents for effective biopriming and evaluation of their effect on plant growth. The study evaluated five biopolymers viz., chitosan, sodium alginate, lignosulfonate, guar gum, and maltodextrin combined with Bacillus subtilis and Azospirillum zeae for seed biopriming in rice. Bioagents compatibility studies confirmed that B. subtilis and A. zeae were compatible, with no inhibition in their growth. Biopolymer and seed compatibility was assessed by imbibing rice seeds in 0.5%, 1%, and 2% biopolymer solutions for 1 h and 24 h, with 1 h imbibition yielding better results than 24 h. Among the different biopolymers used, 0.5% sodium alginate was the most effective, with highest germination rate (83.3%), seedling length (5.98 cm), and seedling vigor index (498) in rice. The incubation of bioagents in biopolymer solutions showed no inhibition in their growth, confirming the compatibility between all the biopolymers and bioagents tested. Based on the compatibility studies, the biopolymer concentrations standardized for seed biopriming in rice were 1% chitosan, 0.5% sodium alginate, 1% lignosulfonate, 0.5% guar gum, and 0.5% maltodextrin, along with a 1 h imbibition time. The coating efficiency of biopolymer with bioagent consortia (Bacillus subtilis + Azospirillum zeae) showed that rice seeds coated with 0.5% sodium alginate maintained the highest population of Bacillus subtilis (42.8 × 10⁸ cfu/g), followed by seeds coated with lignosulfonate (38.12 × 10⁸ cfu/g) after 1h of coating. Similarly, the population of Azospirillum zeae was higher in seeds coated with bioagent consortia and lignosulfonate (27.76 × 10⁸ cfu/g), followed by sodium alginate-coated seeds (26.03 × 10⁸ cfu/g) after 1h. Scanning electron microscopy confirmed the presence of bioagents on the seed 􀏭􀏰􀏮􀀃􀀃 surface, while stereozoom microscopy showed no significant changes in seed size or shape. The effect of seed biopriming on plant growth revealed that rice seeds primed with bioagent consortia and 0.5 % sodium alginate achieved the highest germination rate (100%), while those with lignosulfonate showed the longest seedling length (25.78 cm) and highest seedling vigor index (2487). Additionally, a slight increase in seed weight and volume were observed after biopriming. The bioprimed seeds were stored at room temperature for 6 months, with weekly observations recorded for bioagent survival and germination percentage. After three months, a significant decline in both germination percentage and bioagent survivability were observed. However, seeds coated with bioagent consortia and 1% lignosulfonate maintained bioagent populations up to six months. Seeds coated with bioagent consortia and lignosulfonate also maintained a higher germination percentage (82.66%) even after five months of storage. In contrast, chitosan treated seeds did not showed germination after two months of storage, and bioagent population was declined after three months.The two biopolymer-based bioagent consortia formulations, bioagent consortia + 0.5% sodium alginate and bioagent consortia + 1% lignosulfonate were tested to assess their potential for enhancing the plant growth and yield in rice. The experiment was first conducted in sterile soil and then in non-sterile soil to evaluate the effectiveness of biopriming. Under sterile and non-sterile conditions, plant growth parameters such as plant height and the number of tillers per plant were on par for seeds bioprimed with sodium alginate and lignosulfonate. However, the number of grains per panicle and grain yield per plant were higher in seeds treated with bioagent consortia and lignosulfonate in both sterile and non-sterile conditions. Additionally, the seed treatment with bioagent consortia and biopolymers led to an increase in soil nutrient content, further highlighting the beneficial effects of biopriming. The present study highlights the efficacy of biopolymer-based priming in enhancing plant growth in rice, with 0.5% sodium alginate and 1% lignosulfonate, combined with bioagent consortia, showing promising results. Notably, seeds primed with 1% lignosulfonate exhibited the highest performance, significantly improving plant growth and seed viability, while also offering a cost-effective solution. Furthermore, bioprimed seeds retained viability up to six months. However, field trials are essential tovalidate these findings.