EFFECT OF PACLOBUTRAZOL AND SALICYLIC ACID ON AMELIORATION OF WATER STRESS EFFECTS IN MAIZE
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Date
2019
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ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR
Abstract
A field experiment was entitled “Effect of paclobutrazol and salicylic acid on amelioration of water stress effects in maize” was conducted at Agricultural college Farm, Bapatla during Rabi season of 2018-19 in split plot design with three main plot treatments viz., M1: Control (No water stress); M2 : Water stress at knee high stage (V6 stage); M3:Water stress at cob development stage (VT-R1 stage) and seven sub plot treatments viz., Control (S1), 50 ppm PBZ spray at V6 stage (S2), 0.5 mM SA spray at V6 stage (S2), 50 ppm PBZ spray at VT-R1 stage (S2), 0.5 mM SA spray at VT-R1 stage (S5), 50 ppm PBZ spray at V6 and VT-R1 stage (S6), 0.5 mM SA spray at V6 and VT-R1 stage (S7) in three replications. Observations were recorded on morphophysiological and biochemical parameters at 38, 48, 70 and 80 DAE. Data on yield and yield components were recorded at harvest. The results of the investigation are summarized in this chapter.
Water stress imposed at V6 and VT-R1 stage resulted in decline in leaf area (17.2 & 10.7%), chlorophyll content (19.4 & 24.6%), relative water content of leaves (19.6 & 10.1%), transpiration rate (44.5 & 25.7%), stomatal conductance (44.2 & 46.5%), internal CO2 concentration (15.6 & 16.2%) and photosynthetic rate (33.0 & 33.9%), starch content (41.6 & 18.8%), sucrose phosphate synthase activity (70.1 & 33.7%), invertase activity (65.7 & 28.2%) . Plants treated with SA at V6, VT-R1, at V6 and VT-R1 stages increased the leaf area (1.1 folds), SCMR (13.2, 8.6 & 10.9%), leaf RWC (6.0, 6.2 and 8.6%), PBZ spray at V6, VT-R1, V6 and VT-R1 stages enhanced the stomatal conductance (8.3, 12.5 & 18%), internal CO2 concentration (6.0, 8.2 & 8.4%) and photosynthetic rate (11.9, 11.8 & 14.1% respectively). SA spray at V6, VT-R1, V6 and VT-R1 enhanced the stomatal conductance (12.1, 22.4 & 24.2%) and internal CO2 concentration (7.2, 14.4 & 15.7%) and photosynthetic rate (17.0, 19.8 & 20.0% respectively, starch content (33.0, 23.7 & 23.1%), SPS activity (28.6, 9.6 & 11.2%), invertase activity (31.5, 15.0 & 15.8%), respectively.
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Water stress imposed at both stages enhanced the soil temperature (2.1 & 2.3oC), canopy leaf and shoot temperature (2.4, 1.1 & 2.0, 1.3oC), total soluble sugars (27.0 & 18.2%), activity of catalase (43.1 & 26.2%), SOD (31.7 & 33.3%), peroxidise (49.6 & 28.8%). Spray of PBZ at V6 stage caused 2.0 and 2.2oC decline in leaf and shoot temperature respectively. SA spray at V6 stage declined the leaf and shoot temperature by 3.5 and 3.1oC. The spray of it at VT-R1, V6 and VT-R1 stages declined the leaf and shoot temperature 2.8, 2.8, 1.9 and 1.7oC respectively. SA spray at V6, VTR1, V6 and VT-R1 stages caused decline in total soluble sugars (19.5, 17.8 & 16.9%), activity of catalase (23.8%), SOD (11.3%) and peroxidise (27.5%). The spray of SA at VT-R1,, V6 and VT-R1 stages caused decline in activity of catalase (22.0%), SOD and peroxidise (26.0 & 25.6% respectively), indicating the reduction in oxidation stress and impact of water stress. The effect of PBZ spray was found on par with both SA spray and control.
Water stress imposed at both stages showed decline in dry matter of leaf (37.2 & 39.7%), stem (46.3 & 38.0%), root (41.7 & 43.2%), reproductive parts (35.8%) and total plant (46.3 & 37.3% respectively). Plants treated with SA at V6 stage increased the dry matter of leaf (31.8%), stem (11.8%), root (26.0%), reproductive parts (6.5%) and total plant (21.5%). The spray of SA at VT-R1, V6 and VT-R1 stages increased the dry matter of leaf (17.37 & 19.0%), stem (12.0%), root (34.1 & 32.6%), reproductive parts (10.3 & 11.2%) and total plant (13.5 & 14.2%), respectively. The effect of PBZ spray was found on par with both SA spray and control. Water stress imposed at both stages showed decline in number of cobs plant-1, number of rows cob-1, number of kernels row-1, cob length, cob yield, kernel yield, test weight and shelling percentage. Plants treated with SA at V6, VT-R1, V6 and VT-R1 stages enhanced the number of cobs plant-1 (17.1, 18.6 & 20.1%), number of rows cob-1 (17.5, 18.2 & 19.6%), number of kernels row-1 (9.4, 10.4 & 10.5%), cob length (10.9, 11.2 & 11.2%), cob yield (17.5, 20.2 & 21.6%), kernel yield (20.6, 23.2 & 24.6%), test weight (7.3, 7.8 & 7.6%) and shelling percentage (4.2, 5.0 & 4.9 % respectively). The effect of PBZ spray was found on par with both SA spray and control.
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D5918
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