Influence of zinc nutrition on growth, thermotolerance and yield of chickpea (Cicer arietinum L.)
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Date
2022-08-10
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guntur
Abstract
The present investigation entitled “Influence of zinc nutrition on growth, thermotolerance and yield of chickpea (Cicer arietinum L.)” was undertaken at Agricultural College Farm, Bapatla during rabi, 2020 – 21. The experiment was laid out in split plot design with three main treatments i.e., three dates of chickpea sowing viz., normal sowing (sown on November 10th - (M1)), moderately delayed sowing (sown on November 30th - (M2)) and late sowing (December 20th - (M3)) to expose the crop to late sowing induced heat stress during flowering and pod formation stages, and four sub treatments viz., no zinc application (control – S0), foliar spray of ZnSO4. H2O @ 0.2 % (S1), Zn-EDTA @ 0.3 % (S2) and ZnSO4. 7H2O @ 0.5 % (S3) at pre flowering and pod formation stages in three replications.
The results of the study revealed that, significant differences were observed among the main treatments, sub treatments and their interactions. Plant height decreased significantly under late sown conditions, and the decrease was 12.5 and 10.0 per cent in late sown and moderately delayed sown chickpea crops, respectively. Foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages increased the plant height by 10.0 per cent, over the control plants. The late sown chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M3S3) increased the plant height by 10.6 per cent, over no zinc application (M3S0). Late sown chickpea crop attained 50 % flowering and maturity by 9 days early over the normal sown crop, indicating accelerated flowering and maturity under heat stress condition in the present study. Foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages took significantly more number of days to 50 % maturity compared to control plants.
Leaf area was reduced by 14.2 and 7.1 per cent, and leaf, stem, reproductive parts and total dry matter was decreased by 30.0 and 21.8 per cent; 18.0 and 11.3 per cent; 27.0 and 18.6 per cent and 26.5 and 18.4 per cent in late sown and moderately delayed sown crops, respectively, over the normal sown crop. Among the zinc treatments, foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages increased the leaf area by 14.0 per cent; leaf, stem, reproductive parts and total
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dry matter by 15.8, 17.6, 26.3 and 21.8 per cent, over control plants. Zn-EDTA @ 0.3 % spray came in the second order in increasing the leaf area and leaf, stem, reproductive parts and total dry matter by 9.1, 10.4, 11.8, 16.7 and 14.3 per cent, respectively, over control plants. Normal sown chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M1S3) recorded the highest values of above parameters and the lowest values were recorded by the late sown crop without zinc application (M3S0). Under late sown conditions, the chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M3S3) increased the leaf area and leaf, stem, reproductive parts and total dry mater by 17.5, 12.2, 23.4, 22.0 and 21.5 per cent, respectively, over the late sown crop without zinc application (M3S0).
Thermotolerance parameters such as MII, CSI, RWC and CTD varied significantly by different dates of sowing. Higher MII was recorded by the late sown crop compared to the normal sown crop, indicating increased lipid peroxidation under heat stress (late sown) conditions. Lesser CSI, RWC and CTD were recorded by the late sown chickpea crop compared to the normal sown crop. Foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages decreased the MII values and improved the CSI, RWC and CTD. under late sown conditions (heat stress conditions), foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M3S3) helped in minimizing the damage to the cellular membranes by recording lesser MII values, higher CSI, RWC and CTD compared to the late sown crop without zinc application (M3S0), indicating the role of zinc in amelioration of heat stress especially under late sown conditions.
Net photosynthetic rate, stomatal conductance and transpiration rate were decreased in the late sown chickpea crop by 12.3, 7.0 and 24.8 per cent, respectively, over the normal sown crop. ZnSO4. 7H2O @ 0.5 % foliar spray exhibited superior performance in enhancing net photosynthetic rate, stomatal conductance and transpiration rate by 22.2, 12.3 and 40.7 per cent, respectively, over control plants. Late sown chickpea crop sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M3S3) increased the net photosynthetic rate, stomatal conductance and transpiration rate by 20.2, 9.7 and 40.0 per cent respectively, over untreated plants (M3S0).
SOD activity was increased by 35.4 and 14.0 per cent in chickpea due to late sowing and moderately delayed sowing compared to normal sowing. Protein and zinc contents in seed were also reduced in the late sown chickpea crop. Foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages significantly increased the SOD activity, and protein and zinc contents in seed compared to the untreated plants. Late sown chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % (M3S3) recorded higher SOD activity, higher protein and zinc content in seed, over the crop without zinc application (M3S0).
In late sown chickpea crop, the number of pods plant-1, number of seeds plant-1, test weight and seed yield were decreased by 14.1, 12.6, 5.5 and 17.6 per cent, respectively, over the normal sown crop. Among the zinc treatments, foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages increased the pods per plant, seeds per plant, test weight and seed yield by 17.3, 26.0, 3.4 and 42.6 per cent, over the untreated plants. Under normal sown conditions, the chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M1S3) recorded 21.1 per cent increase in seed yield over the crop without zinc
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application (M1S0), and 21.1 per cent increase over the late sown crop with zinc application (M3S3). Under late sown conditions, ZnSO4. 7H2O foliar spray @ 0.5 % (M3S3) increased the seed yield by 41.2 per cent, over the late sown crop without zinc application (M3S0). ZnSO4. 7H2O @ 0.5 % foliar spray to the late sown chickpea crop recorded higher harvest index compared to the crop without zinc application.
According to the results obtained above, it can be concluded that the morpho- physiological, thermotolerance and photosynthetic parameters; seed yield and its components and quality parameters were drastically reduced in the late sown chickpea crop in the present study, indicating the exposure of the crop to heat stress under late sown conditions during flowering and pod formation stages, that reflected reduction on the above parameters. Foliar spray of ZnSO4. 7H2O @ 0.5 % could improve the growth, yield and its components of chickpea both under normal sown as well as late sown conditions. Zn-EDTA @ 0.3 % came in the second order in improving the above parameters. The use of ZnSO4. 7H2O @ 0.5 % foliar spray at pre flowering and pod formation stages especially under late sown conditions, could alleviate the negative effects of heat stress on growth and yield of chickpea by improving the thermotolerance capacity of the crop in terms of maintaining lesser MII; higher CSI, RWC and CTD and higher activity of SOD, which helped the late sown chickpea crop from the adverse effects of heat stress from flowering to maturity.
Description
Influence of zinc nutrition on growth, thermotolerance and yield of chickpea
(Cicer arietinum L.)