The study was initiated with the aims to determine the variation in growth and yield of winter wheat varieties to pendimethalin at different application rates and to identify the wheat varieties tolerant or susceptible to pendimethalin. A two-year study was conducted on sandy clay loam textured soil containing low organic matter content during the dry season having no or very little amount of rainfall. Eight wheat varieties (BARI Gom 21 to 28) were tested against pendimethalin 33EC applied at its label rate (3 L ha-1), double (6 L ha-1) and three times of the label rate (9 L ha-1). Emergence of all wheat varieties was not adversely affected by pendimethalin even applied at three times higher than the label rate; however, plant heights of BARI Gom 23 and BARI Gom 25 were slightly decreased with increasing application rate. Label rate application of pendimethalin did not decrease the yields of all wheat varieties compared to the control, but BARI Gom 21, BARI Gom 22, BARI Gom 24, BARI Gom 26 and BARI Gom 27 gave their best yields at three times higher of the label rate application. Therefore, the study marked out BARI Gom 21, BARI Gom 22, BARI Gom 24, BARI Gom 26 and BARI Gom 27 as the pendimethalin-tolerant wheat varieties under strip planting system. Additionally, the study confirmed that all the wheat varieties were tolerant to label rate application of pendimethalin; however, BARI Gom 23, BARI Gom 25 and BARI Gom 28 were susceptible to the higher rate of pendimethalin.
Key words: Herbicide; minimum tillage; plant growth; tolerance; wheat