الفهرس 
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Abstract
The present i n v e s t i g a t i o n was undertaken (a) t o study the inheritance of r e s i s t a n c e t o r i c e stem borer Chilo agnmemnon Bles. and (b) t o determine the probable mechanism of r e s i s t a n c e (on the basis of the extent of association between the l e v e l of resistance and some of the agronomic c h a r a c t e r i s t i c s ) . The s a l i e n t findings have been summarized below: 1- Varietol screening for r e l a t i v e resistance t o r i c e stem borer: Twenty v a r i e t i e s belonging t o indica and ~eponica subspecies were screened for resistance a t d i f f e r e n t stages of growth under a r t i f i c i a l and n a t u r a l i n f e s t a - t i o n during 1979 and 1980 seasons. A t seedling stage, a l l the v a r i e t i e s were found to show r e s i s t a n t r e a c t i o n , the dead heart incidence being l e s s than 5%. However, during tillering stage, 15 v a r i e t i e s were r e s i s t a n t showing very low percentage of dead heart incidence, while the -remaining f i v e variet5es were susceptible and moderately susceptible with dead heart percentage exceeding 15%. Screening of the same twenty v a r i e t i e s a t reproductive phase revealed t h a t among the 15 r e s i s t a n t v a r i e t i e s a t til-lering s t a g e ; f i v e v a r i e t i e s were moderately r e s i s t a n t and ten were r e s i s t a n t.