JAISANI, B. G.AMIN, VISHNUPRASAD CHATURBHAI2018-04-102018-04-101983http://krishikosh.egranth.ac.in/handle/1/5810043182Damping-off disease of tobacco nursery caused by Pythium aphanidermatum is a serious problem for successful nursery raising. The severity of pre and post emergence damping of may lead to very poor seedling germination ability. High humidity, high temperature and soil moisture show disease symptoms in very short time spell. Due to its easy control by spray of Bordeaux mixture or any other copper compound, it has not been considered a serious problem worth paying attention by the plant breeders. But due to the spiralling prices of copper compounds, lime and labour charges, it is highly essential to evolve damping-off resistant/tolerant cultivars to keep the nursery cost at low level.enPLANT BREEDING AND GENETICS, AGRICULTUREA STUDYThesis