Production potential and nitrogen use efficiency of inter specific and intra hirsutum cotton hybrids under graded levels of nitrogen and weed control methods

Abstract

. . A field study was conducted during the winter seascn of 1997 and 1998 at Tamil Nadu Agricultural University, Coimbatore. Two hybrids (inter specific TCHB 213 and intra hirsutum Surya ) were evaluated for their production potential under 3 N levels (90. 120, and 150 kglha) and 4 weed control methods (Pendimethalin 1.0 kg 1 hand weeding, glyphosate 1.0 kg 1 hand weeding, hand weeding twice and unweeded control). The hybrids were grown following the recommended spacing of 90 cm x 60 cm for Surya and 120 cm x 60 cm for TCHB 213 . Among the hybrids, TCHB 213 gave better yield attributes and yield , on per plant basis. But Surya gave significantly more yreld than TCHB 21 3 on t unit area basis. The response to applied N was increasing at increasing rate up to the highest level (150 kglha) of N. But the N use efficiency decreased with increase in N level. Among the weed control treatments, hand weeding twice recorded significantly higher seed cotton yield and N use efficiency which was closely followed by glyphosate hand weeding.