Evaluation of Salt Tolerance for Improved Rice Lines in terms of Agronomic Parameters

抄録

Soil salinity has become a serious threat to crop productivity worldwide. Salt tolerance for rice varieties vary with different stages against salinity. This study was to evaluate the effect of three different levels [0.2, 6.0, and 8.0 dS m^-1] of salinity on the growth and yield of improved rice lines at different growth stages. This study was conducted as two-factor factorial in a randomized complete block design with three replications at Yezin Agricultural University in 2017 and 2018. After screening at seedling and vegetative stages, the selected rice lines were grown at three different salinity levels [3.3, 6.0, and 7.6 dS m^-1] in the field. Among the one hundred improved rice lines, thirteen lines were tolerant to 8.0 dS m^-1 during three weeks of application at seedling stage. Studies at vegetative stage showed that these thirteen lines were tolerant to 6.0 dS m^-1 during six weeks of application. However, seven rice lines were moderately tolerant to 8.0 dS m^-1 during six weeks of application in term of leaf mortality. In the field experiment, all seven rice lines were tolerant to 6.0 dS m^-1 at all growth stages, whereas death occurred at 7.6 dS m^-1. All agronomic parameters such as tiller numbers, panicle numbers and grain numbers per panicle were grown up to maturity under 6.0 dS m^-1 at field condition. All these parameters were found to be major cause of yield reduction under saline conditions.