Effect of growth regulation on growth and yield attributes of summer moongbean [Vigna radiata (L.) Wilczek]

A field experiment was conducted during summer season of 2013 in the Department
of Agronomy, Punjab Agricultural University, Ludhiana, Punjab to study the effect of growth
regulation on growth and yield attributes of summer moongbean. The field experiment
comprising eight treatments viz., control and seven growth regulation treatments (detopping,
MC (mepiquat chloride) @ 200, 250 and 300 ppm applied once at 35 days after sowing
(DAS) and twice at 35 and 45 DAS was conducted in a randomized complete block design
(RCBD) with four replications. The grain yield obtained with foliar application of MC @ 250
ppm at 35 and 45 DAS (10.05 q/ha) was significantly higher than control (6.70 q/ha).
Various growth parameters and yield attributes (dry matter accumulation and number of
pods per plant) were also significantly higher with MC @ 250 ppm (35 and 45 DAS) as
compared to control. Detopping resulted in highest leaf area index (LAI), whereas all other
growth regulation treatments were significantly better than control. Detopping resulted in
significant reduction in plant height than control but was statistically at par with two
applications of MC @ 250 and 300 ppm and single application of MC @ 300 ppm (35 DAS).
Flower drop per plant was significantly reduced by two applications of MC @ 300 ppm.
Quality parameters such as nitrogen and protein content in grains remained unaffected
by growth regulation treatments. Nodule count and weight per plant were also unaffected
by growth regulation treatments. Similarly, no effect on crop phenology was observed by
any of the applied treatments.