Effect of Early Post-Emergence Herbicides on Photosynthetic Pigments and Yield in Greengram (Vigna radiata L.)

Aims: To study the influence of early post-emergence herbicides on photosynthetic pigments and yield in greengram.

Study Design: Randomized Block Design.

Place and Duration of Study: Field experiment was conducted at Tamil Nadu Agricultural University, Coimbatore, India during summer 2022.

Methodology: The experiment was laid out with three replications having nine treatments comprising of weedy check, different ready mix early post-emergence herbicides, two hand weedings and weed free. The chlorophyll content mg g-1 in the leaf sample was recorded at 30, 45 and 60 DAS. Grain yield and haulm yield was also calculated and expressed in kg ha-1.

Results: Pre-emergence (PE) application of Pendimethalin 30% EC @ 1 kg a.i ha-1 on 3 DAS followed by (fb) Early post-emergence (EPoE) Imazethapyr 10% SL @ 100 g a.i ha-1 + Quizalofop-ethyl 5% EC @ 50 g a.i ha-1 (Tank mix) on 15 DAS significantly recorded highest value in all photosynthetic pigments viz., Chlorophyll a (1.105 mg g-1), Chlorophyll b (0.402 mg g-1), Total chlorophyll (1.601 mg g-1), Chlorophyll ab ratio and Carotenoids (0.413 mg g-1), whereas higher grain yield (908 kg ha-1) is achieved by the Pre-emergence (PE) application of PE Pendimethalin (30% EC) @ 1 kg a.i ha-1 on 3 DAS followed by (fb) Early post-emergence (EPoE) Propaquizafop 2.5% + Imazethapyr 3.75% ME Ready mix (RM) @ 125 g a.i ha-1 on 15 DAS.

Conclusion: Among the early post-emergence herbicides, Imazethapyr 10% SL @ 100 g a.i ha-1+ Quizalofop-ethyl 5% EC @ 50 g a.i ha-1 (Tank mix) on 15 DAS shown significant results in all the photosynthetic pigments and Propaquizafop 2.5% + Imazethapyr 3.75% ME Ready mix (RM) @ 125 g a.i ha-1 on 15 DAS shown significant results in the yield by suppressing the weeds.