Molecular Basis of High Temperature Stress Effect on Grain Quality of Aromatic and Basmati Rice (Oryza Sativa L.)

Abstract

Heat stress is the rnajor problern for agriculture throughout the world. lncrea c in • tern perature at flowering stage and grain filling stage stage of rice by 5°C in day tirne and 2°C in night tirne tern perature over arnbient ternperaturc leads to deterioration of grain quality and yield. Total 15 Bas1nati and arornatic rice genotypes arc selected out of 35 genotypes studied for genetic diversity. The study of high ternpcrature effect on grain quality including Nagina 22 non arornatic rice used as heat tolerant check, \Vas carried out on 15 genotypes. The grain quality paratneters ie Arorna~ Gel consistency and t\lkali spreading value are highly affected~ \Vhile arnylose percentage decrease under high ternpcrature. Proline content is increased~ \vhile GABA is decrcas~d in bnstnati rice grain under high ten1perature. Starch granule structure of basrnati rice is also atTccted and und~r high tcn1perature except non-basrnati Nagina 22. The g~ne expre sion analy "' i"' of 13ADll-, GB,.~SI ( H'-\), and Pro 7 gene reveals that these genes ure t;itht;r up regulatc:d or do,vn regulated d~,pending on variet)' and gro\vth stagtjs of grain~ und ~r high ltintpernturt::.