Effect of Seed Hardening with Chemicals on Drought Tolerance Traits and Yield in Chickpea . ( Cicer arietinum

A field experiment was conducted to study the effect of seed hardening with various chemicals on bio-chemical components and yield in chickpea. (Cicer arietinum. L).during Rabi 2007,under rain fed conditions. Significantly higher seed yield was recorded in seed hardening with CaCl2 -2% ( 26.32q per ha.) followed by Cycocel -1000ppm (23.54 q per ha.) and succinic acid 20ppm (23.44 q per ha.) as compare to control (19.04q per ha.). The increased seed yield in seed hardening with CaCl2-2% may be attributed to increase in the total chlorophyll, chl-a. and chl-b chlorophyll stability index, proline content ,relative water content, coupled with lower of specific leaf area. as compare to control. Thus It indicates that seed hardening modifies the physiological and biochemical nature of seeds so as to get the characters that are favorable for drought tolerance which more so with CaCl2-2%. Further, It is also evident from the results that the increased seed yield in seed hardening with CaCl2-2% is associated with the increased morphophysiological traits like plant height ,Number of leaf lets, leaf dry matter and total dry matter accumulation, leaf area per plant and Harvest index.


Introduction
Chickpea (Cicer arietinum.L.) is a major Rabi season pulse crop in southern peninsular India.It is generally grown on conserved moisture and moisture in the soil profile gradually recedes as the crop grows.As a consequence, plant experiences progressively increasing degree of terminal moisture stress.Thus, soil moisture stress assuming a major limiting factor for determining the growth and yield of chickpea (Verma and Pramilakumari , 1978).Therefore there is a need to identify suitable ameliorative measures to overcome the moisture stress effect.. The pre-sowing seed hardening with chemicals is one of the simple technique being employed to modify the marpho-physio-biochemical nature of seed, so as to induce the characters that are favorable for drought resistance.Keeping these views the investigation was under taken to study the effect of seed hardening chemicals on growth and yield in chickpea.

Determination growth and physio-biochemical observations
The plant height was recorded from base of the plant to tip of the main stem.The leaf are per plant was computed by graphic method.Number of leaf lets, Total dry matter and its distribution in leaf stem and reproductive parts were worked out from the tagged five plants and average was computed and presented on per plant basis.The total chlorophyll, Chl-a and Chl-b were estimated by using disulphoxide solvent as described by Hiscox and Isrelstam (1979) and was expressed as mg per g of fresh weight..The free proline content was estimated as per Bates et al (1973).The relative water content (RWC) was estimated by method described by Barrs and Weatherly (1962).The determination of epi-cuticular content in leaf at 80DAS was done as per Eberson et al (1977) and was quantified by the help of standard curve drawn by using cabowax-3000 and was expressed as mg per dm2.

Morpho-physiological parameters
The data on morpho-physiological parameters of chickpea revealed, significantly higher plant height (48.1cm) in seed hardening with CaCl 2 -2% ,where as lower plant height in cycocel-1000ppm.This clearly indicates mode of action differs for the chemicals studied.Similarly in finger millet seed hardening with CaCl 2 2% improved the plant height and was due to redistribution of resources leading to cell enlargement and cell division (Karivartharaju and Ramkrishna (1985).The mechanism of reduction in plant height in seed hardening with Cycocel-1000ppm to be due to reduced cell size and cell thickening (Ginzo-1977).Similar results were reported by Dighe et all.1983 in Wheat. .Increase in TDM, ,leaf dry matter, stem dry matter and redistribution of dry matter in reproductive parts is noticed with seed hardening with CaCl2-2% as compare to control..In addition ,more number of leaf lets and leaf area is also more with seed hardening with CaCl2-2%.Thus, TDM and its partition and leaf area were important parameters to boosting the source sink relationship, which is evident from the improvement in the yield and yield parameters. (Table 1).

Biochemical parameters
The data on biochemical parameters of chickpeaTable-2) as influenced by seed hardening chemical revealed, significantly higher chlorophyll content, chl-a, and chl-b in seed hardened with Cycocel1000ppm followed by succinic acid 20ppm and CaCl 2 -2% as compare to Control.It may be due to maintenance of cell turgidity, denser cytoplasm and inhibition of chlorophyll breakdown.In addition, significantly higher Chlorophyll stability index, higher relative water content, proline content and epicuticular wax coupled with lower SLA. is being recorded in seeds hardened with CaCl 2 -2% followed by Cycocel 1000ppm and succinic acid 20ppm.Similar results have been noticed by Cheema,et al (1975), in barley and wheat Shasidhar et al (1981) in Ground nut and Ramesh (2004) in sorghum.Who reported increase in RWC, Chlorophyll and Proline in seed hardened plants?

Yield and yield attributes
Significantly higher seed yield was recorded in seed hardening with CaCl 2 -2%(26.32q/ha)followed by Cycocel-1000ppm (23.54q/ha.) and Succinic acid -20ppm (23.44q/ha.)over control. .The increase in the yield in seed hardening with CaCl2-2% may attributed to increase in the yield components mainly 100 seeds weight., seed yield per plant and harvest index and acquisition of drought tolerance traits general.. However control recorded lower yield and lower mean value for yield components.The results are in agreement with the findings of Mishra and Dwivedi,.(1980),Who reported that treating wheat seeds with 0.25% CaCl 2 or 2.5% KCl increased the grain yield compare to control.On the other hand increased drought tolerance and grain yield in sorghum over control under dry condition was reported by Patil et al. (1987).

Conclusion
The pre sowing seed hardening with CaCl 2 -2% improved yild of chickpea .overcontrol.This simple technique may be employed by the growers to realize the potential yield.

Table 1 .
Effect of seed hardening chemicals on morho-physiological traits in chickpea

Table 2 .
Influence of seed hardening chemicals on biochemical components in chickpea

Table 3 .
Influence of seed hardening chemicals on yield and yield traits in chickpea.