الفهرس 
Genetical studiesOnly 14 pages are availabe for public view
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Abstract
The present investigation was conducted t o identify the major fungi causing brown spot on r i c e plant, t o study the d i f f e r e n t i a l reaction of some r i c e v a r i e t i e s t o brown spot at different stages of growth and t o determine the mode of inheritance of f i e l d reaction to the brown spot disease. 1. Coc hliobolug @,yabeanus the perfect stage of Helminthoseorium or,y-zs, Nigrospora -cr, y_z_ae, Epicoccum Goyzae, and hlternaria a., were isolated from r i c e diseased leaves
and kernels c o l l e c t e d in 1973 at Sakha Agricultural Experimental Station. CoChliobolus mLy abeanus was the most important fungus among the i s o l a t e d fungi. 2. In 1974 and 1975 seasons 165 d i f f e r e n t r i c e v a r i e t i e s belonging t o japonica and indica types were screened t o the brown spot disease a t the s e e d l i n g , a d u l t p l a n t , and kernel stages. 3. Five v a r i e t i e s were highly r e s i s t a n t , 53 v a r i e t i e s were r e s i s t a n t , 37 moderately r e s i s t a n t , 27 moderately susceptible and 33 susceptible at the s e e d l i n g s t a g e . 5 varieties were highly r e s i s t a n t , 25 v a r i e t i e s were r e s i s t a n t , 27 moderately rests tant, 27 moderately susceptible,