EFFECT OF THREE STERILIZING AGENTS ON SEED VIABILITY, SEEDLING VIGOR AND OCCURRENCE OF SEED-BORNE BACTERIAL PATHOGENS OF TWO TOMATO CULTIVAR

Abstract

Efficient seeds surface sterilization and germination is a precondition for successful regeneration and transformation of tomato. Seeds from two tomato cultivars (UTC-18 and F1-mongal) were used in this study. The seeds were treated with sterilizing agents, which included ethanol (70% v/v), hydrogen peroxide (3% v/v) and sodium hypochlorite (2% v/v). Treated and control seeds (30 seeds per plate) were placed on Nutrient agar (NA) amended with 2-3 drops of Benlate (0.5% w/v). The occurrence of Xanthomonas campestris pv. vesicatoria, Pseudomonas syringae pv. tomato and Clavibacter michiganensis subsp. michiganensis gave a good indication of the results. At seventh day after sowing, percent germination was 96.67% for UTC-18 followed by 95.30% for F1-mongal, when ethanol was used for surface sterilization and these values were not significantly different (p ≤ 0.05) from 93.30% in F1-mongal when NaOCl was used as sterilizing agent. At 14th day after sowing, the highest percentage seeds germination of 98.00% was recorded for ethanol-F1-mongal treated seeds, which was not significantly different from 97.72% in NaOCl-F1- mongal treated, 97.00% in ethanol-UTC-18 treated and 96.67% in NaOCl-UTC-18 treated seed lots. Application of sterilizing agents significantly reduced microbial loads, improved seedlings quality and vigor. Thus, the use of ethanol at 70% and NaOCl at 2% for 5 min would be suitable as tomato seeds surface sterilizing agents to reduce microbial loads, which would produce healthy seedlings for providing cotyledon and hypocotyls explants for use in tissue culture.