Computation of LC50 against Spodoptera litura (Fab.) for Bacillus thuringiensis isolates from native soil samples of Andhra Pradesh

Abstract

The experiments were conducted at the Department of Seed Science and Technology during 2017 on mechanization of seed priming by standardizing the spin drying duration of the Seed Priming cabinet, to enhance the seed viability per cent, embryonic growth of the solanaceous vegetables viz., brinjal, chilli and tomato seeds. The seeds were subjected to conventional hydropriming which involves manual soaking, draining and shade drying and it was compared with mechanized seed priming and spin drying for 1, 2, 3, 4 and 5 min. Hydropriming (48 hrs) and spin drying for 1 min. was standardised for chilli, likewise, 48 hrs + 2 min. for both brinjal and tomato. The hydroprimed and spin dried seeds along with hydroprimed + shade drying and control seeds were subjected to anatomical study by using Euromex Holland’s Image Version 1.0. The results indicated that high seed viability per cent 19.3, 30.7 and 76.0 was observed in hydroprimed + spin dried seeds of brinjal, chilli and tomato respectively, over non primed seeds. Apart this, Spin dried seeds of all the above said crops showed significant difference in radicle and cotyledon length over nonprimed seeds. In which, Spin dried seeds of tomato showed 116.7 and 22.4 per cent increase in length of radicle and plumule + hypocotyl length, respectively over non primed seeds. Brinjal spin dried seeds showed hike in radicle length and plumule + hypocotyl length of 35.8 and 95.3 per cent respectively over non primed seeds. In chilli, spin dried seeds radicle length and plumule + hypocotyl length was increased 42.1 and 3.2 per cent, respectively over non primed seeds.