Abdul Rahiman Kunju, OTampi, A MBhaskaran, CKAU2019-01-292019-01-291992Agricultural Research Journal of Kerala, 30(1), 38-41.http://krishikosh.egranth.ac.in/handle/1/5810092797Out of the nine constraints identified in evolving and spreading improved rice varieties, lack of facilities for evolving specific varieties suited to certain rice pockets of Kerala ranked first as percieved by the research subsystem. Non-filling up of post of scientists, lack of facilities to multiply seeds of improved varieties and for onfarm teaching of farmers were other important constraints in the descending order. Susceptibility to pests and diseases, requirement of heavy dose of fertilizers, poor cooking quality and low straw yield were the most important constraints in spreading and adopting improved rice varieties as perceived by extension, client and input subsystems.ennullArticle