U.V. MummigattiAnitha2016-11-212016-11-212012http://krishikosh.egranth.ac.in/handle/1/86814Investigations comprised of laboratory, field and pot experiments to elucidate physiological and biochemical basis of resistance to Purple Seed Stain (PSS) disease in soybean conducted at UAS, Dharwad during kharif-2011. Recording of purple seed stain incidence taluk wise in northern Karnataka revealed that Chikkodi recorded maximum PSS severity with 7.24 per cent followed by Bailhongal (6.29%). Badal Ankalagi village of Bailhongal taluk recorded highest incidence of 12.93%. Thus the disease incidence varies with weather conditions and agronomic practice. Glass house and in vitro studies on PGPR and ISR elicitors revealed that seed treatment with Trichoderma harzianum @ 1000 ppm showed more resistance to PSS disease and recorded highest peroxidase activity. Field screening of 50 germplasm lines to PSS showed that 14 lines as highly resistant, 9 resistant, 9 moderately resistant, 8 susceptible and 10 lines as highly susceptible. Correlation study between disease susceptibility and bio-physiological parameters indicated that there was positive correlation between chlorophyll and RWC (r = 0.035), while chlorophyll and RWC were negatively correlated (r=-0.117 and r=-0.035, respectively) with disease severity. Seed germination study of seed priming with bioagents and fungicides under lab condition indicated significantly maximum germination per cent in seeds primed with combifungicide carboxin 37.5% + thiram 37.5% @ 0.2% (99%) followed by carbendazim @ 0.2% (94%). Whereas, field performance of the primed seeds indicated that Bacillus subtilis @ 0.6% recorded significantly higher seed yield (3221 kg ha-1) followed by captan 70% WP + hexaconazole 5% EC @ 0.2% (3116 kg ha-1) and carbendazim 25% + mancozeb 50 WS @ 0.2% (3083 kg ha-1). Thus, it may be concluded that priming of soybean seeds with the combifungicides viz, captan 70% WP + hexaconazole 5% EC @ 0.2%, carbendazim 25% + mancozeb 50% WS @ 0.2% or with bioinoculant Bacillus subtilis @ 0.6% controlled PSS disease substantially.Thesis