Study on physicochemical properties of rice landraces for amylose, gel consistency and gelatinization temperature

Rice grain quality depends on physical, biochemical, cooking quality and organoleptic characters. Grain quality analysis in rice involves a physicochemical and sensory tests. In this study, morphologically different 60 rice landraces of Tamil Nadu along with ADT (R) 45 as a check variety were used for physicochemical analysis based on the amylose content (AC), gel consistency (GC) and gelatinization temperature (GT). Highly significant variation (p<0.05) was observed among the 60 landraces for all the characters. Most of the landraces registered low amylose content. Nine landraces exhibited high and 18 landraces exhibited intermediate AC. In the case of a gel consistency, most of the landraces exhibited soft GC, while four landraces viz., Athur kichadi, Kavuni nel, Uppu mulagai and Valan registered medium gel. With respect to GT, all the landraces exhibited high to intermediate GT except Kattu ponni, Kavuni nel and Sugandni samba which were identified with low GT. The check variety exhibited intermediate amylose, soft gel and high gelatinization temperature. The landraces Chennellu, Kattu vanipam, Kichali samba, Kuttala samba, Pome, Revathi, Samba masanam, Saysree, Sembalai, Sivappu Kavuni, Soora kuruvai, Thailand Kavuni, Thanga samba and Thirupathisaram were identified as promising landraces based on intermediate amylose, soft gel consistency and intermediate gelatinization temperature. High genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) coupled with high heritability and high genetic advance as a percentage of mean were recorded in all three characters indicating additive gene action. This indicates that there was a low environmental influence on the expression of these characters and hence one can practice selection. The results of this study provide vital information on amylose content gel consistency and gelatinization temperature of various rice landraces which can be utilized in a breeding programme directed towards improving the cooking and eating quality. Landraces with high amylose content can be further studied for identifying landraces with high resistant starch and low Glycaemic Index. Key words: Amylose content, Gel consistency, Gelatinization temperature, landraces, rice