EFFECT OF SOWING DATE AND GIBBERELLIC ACID ON WATER RELATIONS AND YIELD OF LENTIL UNDER RESIDUAL SOIL MOISTURE CONDITION

Abstract

The experiment was conducted at the farm of Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka, Bangladesh during the period from November 2012 to March 2013 to study the effect of gibberellic acid and sowing date on water relations and yield of lentil (variety: BAR! Masur-6) under residual soil moisture condition. The experiment consists of two factors: Factor A: Sowing date (3) - S,= 27 November, S2= 7 December and S3 = 17 December; Factor B: GA3 application (just before flowering) (3 levels) - G = 0 ppm (Control); G1 00 = 100 ppm and G 200 = 200 ppm. The two factors experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Data on different water relations, yield and yield contributing characters were recorded and variation was observed. Highest exudation rate (ER) (11.22 mg br') and relative water content (RWC) (78.02%) was found from S (sowing on 27 November), in contrary lowest ER (4.67 mg br") and RWC (70.42%) was found from S3 (sowing on 17 December). Maximum days to first flowering (46 DAS), pod maturity (98.89 DAS), pods per plant (39.91), pod length (2.35 cm), seeds per pod (1.90), thousand seeds weight (18.58 gin), seed yield (0.98 t ha') and stover yield (1.24 t ha') was found from sowing on 27 November. Whereas, minimum days to first flowering (41 DAS), pod maturity (91.11 DAS), pods per plant (15.38), pod length (1.44 cm), seeds per pod (1.18), thousand seeds weight (15.55 gin), seed yield (0.54 t ha') and stover yield (0.67 t ha') was found from sowing on 17 December. Highest ER (10.89 mg hi') and RWC (79.12%) was found from G2 (200 ppm GA3), in contrary lowest ER (5.33 mg hi') and RWC (70.28%) was found from G0 (control). For 200 ppm GA 3 application days to first flower bud initiation was earlier (42.67 DAS) than 100 ppm GA3 (43.33 DAS) and control (44.44 DAS). Highest pods per plant (32.08), thousand seeds weight (18.38 gin), seed yield (0.82 t hi') and stover yield (1.13 t ha') was found from G200 (200 ppm GA3 ). Whereas, lowest pods per plant (22.04), thousand seeds weight (16.44 gm), seed yield (0.69 t ha') and stover yield (0.80 t ha') was found from G0 (control). For sowing on 27 November seed yield was increased 17.65% and 29.4 1% due to 100 ppm and 200 ppm GA3 application respectively over control. For sowing on 7 December seed yield was increased 14.49% and 18.84% due to 100 ppm and 200 ppm GA3 application respectively over control. But, the effect of GA3 application was insignificant on yield for sowing on 17 December. It was revealed that yield of BARI Masur-6 can be significantly increased by applying 200 ppm GA3 and 100 ppm GA3 for sowing on late November and early December respectively. But, for sowing on late December foliar application of GA3 is useless under residual soil moisture condition as application of GA 3 did not increase yield significantly.