Optical Characteristics, Thermal use Efficiency, Yield and Yield Attributes of Bt Cotton under Different Plant Spacing and Fertilizer Levels

Field trail was conducted at the Research Farm of Cotton Section, Department of Genetics & Plant Breeding, CCS HAU, Hisar (Lat 29ᵒ 10' N, Long 75ᵒ 46' E and 215.2 m msl) during Kharif season of 2015. The experiment was conducted in split-split plot design with three replications. Three varieties viz. V1=RCH 602, V2=RCH 650 and V3=Bunty were kept in main plots while three spacing viz. S1=67.5 cm × 45 cm, S2=67.5 cm × 60 cm and S3=67.5 cm × 75 cm with three fertilizer levels i.e. F1=RDF, F2=125 % of RDF and F3=150 % of RDF application of the recommended dose were kept in subplots. Recommended dose of fertilizer (RDF) was N:P:K=175:60:60 kg ha-1. Optical characteristics, thermal use efficiency (TUE) were computed along with yield and yield attributes were also studied. V1 (86.6 %), S3 (84.8 %) and F3 (85.1 %) absorbed maximum PAR among all the cv., plant spacing and fertilizer levels. TUE was found higher in the V1 (0.35 g/m²/℃ day), S3 (0.34 g/m²/℃ day) and F3 (0.29 g/m²/℃ day) among all the cv., plant spacing and fertilizer levels. Number of bolls plant-1 were found higher in V1 (21.0), S3 (14.7) and F3 (16.0) among all the cv., plant spacing and fertilizer levels. Among all the cv., plant spacing and fertilizer levels boll weight (g) were found higher in V2 (3.89 g), S2 (3.66 g) and F2 (3.62 g). Sympodial branches plant-1 at harvest were found highest in V1 (23.7), S1 (21.0) and F1 (21.4) among all the cv., plant spacing and fertilizer levels. In seed cotton yield V1 (1248.7 kg ha-1), S3 (1120.7 kg ha-1) and F2 (1094.3 kg ha-1) have the maximum yield as compare to other cv., plant spacing and fertilizer levels.