Effect of Chitosan on Yield of Rice Plants Subjected to High Temperature at Different Growth Stages

Abstract

Chitosan is a bio-substance that stimulates growth and increases plant yield. It also elicits plant
immune system under stress condition. The objective was to test chitosan effect on rice yield after being
subjected to high temperature at different growth stages. The experimental design was split plot in
randomized complete block design with four replications. Main plot was four growth stages of rice plant
subjected to high temperature (seedling stage, tillering stage, panicle initiation stage and normal
temperature (control) and subplot was chitosan application and no chitosan. The results found that rice
plants subjected to high temperature at tillering stage showed higher tiller numbers per plant and lower
unfilled grain percentage when compared to those of the other growth stages. Application of chitosan helped to increase leaf greenness. Furthermore, interaction between rice growth stage subjected to high
temperature and chitosan application was significantly found. Rice plants sprayed with chitosan and then
subjected to high temperature at tillering stage showed the highest grain yield and filled grain but the
lowest unfilled grain. Whereas, rice plants subjected to high temperature at panicle initiation stage and no
chitosan exhibited the lowest grain yield and filled grain but the highest unfilled grain. From this study, it
could be concluded that foliar application of chitosan tended to increase growthand yield of rice plants
under high temperature, especially at tillering stage.