Seed Priming: A Low Cost Input for Yield Maximization of Rainfed Chickpea

Chickpea is one of the most important winter pulse crops of India, grown both under rainfed and irrigated conditions. The productivity of chickpea has dropped due to various constraints such as biotic and abiotic factors. Optimum plant population is of primary importance for optimizing field production of any crop plant. At suboptimal conditions of environment, poor seed germination and subsequently poor plant population is a common phenomenon. It has been reported that one of the major obstacles to high yield and production of crop plants is the lack of synchronized crop establishment due to poor weather and soil conditions (Mwale et al., 2003). In Maharashtra chickpea is grown both under conserved soil moisture and irrigated situations. Moisture availability is the major constraint of rainfed chickpea in Maharashtra. Poor and erratic germination, weak seedlings and less plant population are major causes of low chickpea productivity in the Maharashtra. Inadequate soil moisture has negative effects on seedling emergence, germination, growth, flowering, pod set and seed yield. Rapid germination and emergence are an important factor of successful establishment of the crop. It is reported that the seed priming is one of the most important developments to help rapid and even germination and emergence of seeds and to increase seed tolerance to adverse environmental conditions (Harris et al., 1999). Seed priming with water or different osmotic solutions before sowing are an effective mechanism to increase germination, seedling establishment and uniformity by balancing available soil moisture (Parera et al., 1994). Seed priming could be done either by hydro priming or osmotic priming with different salts and growth regulators. The seed priming process affects activity of different enzymes, especially amylase and increase mobilization of starch granules in cotyledons thus, stimulating germination, growth and final yield (Kaur et al., 1988). Information on the effect of seed priming on growth and yield of chickpea under rainfed conditions is very meager. Considering the above factors, research work on chickpea was carried out to evaluate the effect of different seed priming treatments on crop growth, yield contributing character and yield of chickpea.

The present experiment was conducted at the Agriculture Research Station (Dr. PDKV), Buldana, Maharashtra, India during 2016-17 to 2019-20 (four years). The soil of experimental plot was clayey and slightly alkaline (pH 8.0), with available nitrogen (230 kg/ha), phosphorus (21 kg/ha) and potassium (365 kg/ha) content. Geographically Buldana is situated between 20°32'07.27N 76°11'24.43E and its mean height above sea level is 654 m. It receives most of the rainfall from South-West monsoon, commencing from middle of June. The normal monsoon season rainfall approximates to about 720 mm receives in about 40 to 45 rainy days from the middle of June to September. For studying the effect of seed priming on Chickpea (Cicer arietinum) under rainfed conditions, randomized block design was used.
       
The details of the treatments and symbols used are given in Table 1. In all, there were 12 treatments replicated three times. The experimental field was laid out in 36-unit plots, each plot measuring 25.20 m² (6.0 m × 4.2 m). There were fourteen rows of chickpea crop in each plot and 60 plants in each row. One row of crop from both sides of length and also both sides of breadth were left as guard rows. The net plot consisted of twelve rows with fifty-eight plants per row (5.8 m × 3.6 m).
 

       
Seeds of chickpea variety JAKI-9218 were sown @ 75 kg/ ha with the spacing of 30cm between rows and 10cm between plants (33 plants/m²) on third week of October during all the four years of experimentation. A fertilizer dose of 25 kg N, 50 kg P₂O₅ and 30 kg K₂O/ha through urea, single super phosphate and muriate of potash were applied at the time of sowing (basal application) to all the plots. Seed priming (for four hours) of chickpea seed was done as per the treatments. The details of treatments, volume of water and quantity of chemicals used for seed priming of chickpea crop are given in Table 1.
       
Timely recommended plant-protection measures for chickpea crop were followed to save the crop from the pests and diseases. The chickpea crop was harvested manually.
       
The data on various biometric parameters recorded from the experimental plots were statistically analysed as suggested by Panse and Sukhatme (1995) by using ‘F’ test at P=0.05.

Pooled results of four years (2016-17 to 2019-20) of the experiment are presented and the interpretation of the data are made on pooled mean basis.
 
Effect of seed priming on growth and yield contributing parameters of chickpea
 
The seed priming of chickpea with nutrients and growth regulators influenced the growth and yield parameters of chickpea crop (Table 2 and 3).
 

 

 
Plant population
 
Seed priming with 0.5% potassium nitrate for 4 hours recorded significantly higher initial plant population (30.4 plants/m²) than the control treatment (24.1 plants/m²). However, it was at par with all other seed priming treatments. Similarly, seed priming with 0.5% potassium nitrate for 4 hours recorded significantly higher plant population (28.5 plants/m²) at harvest than the control treatment (21.70 plants/m²). However, it was at par with all other seed priming treatments. Seed priming with 0.5% potassium nitrate resulted in 26% more plants/m² than the control treatment at the initial stage. At harvest also seed priming with 0.5% potassium nitrate recorded 32% more plant population than the control treatment. The favourable effect of seed priming observed may be attributed to imbibition, enzymes activation, stimulated hypocotyl growth, increased cell elongation resulting in faster emergence and positive effect on germination. Similar observations were also recorded by Choudhary et al., (2008) and Patil et al., (2018) in chickpea crop.
 
Plant height
 
Plant height is important morphological parameter exhibiting direct relationship with grain yield. It is a visible measure of plant growth and is a function of leaf emergence and internodal elongation. Since leaves and branches born on stem, leaf area development and biomass production showed close relationship with plant height. Seed priming with 1.0% potassium nitrate for 4 hours recorded significantly taller plants (41.49 cm) than the control (36.68 cm), seed priming with Chlormequat chloride 50 ppm for 4 hrs (38.78 cm) and seed priming with Chlormequat chloride 100 ppm for 4 hrs (38.65 cm). However, it was at par with all other seed priming treatments. The enhancement of chickpea plant primed with 1% potassium nitrate might be due to the early plant emergence and more plant population/ m² because of seed priming which might have created supportive competition among the plants for light and resulted in taller plants. Similar observations were recorded by Patil et al., (2018) and Lhungdim et al., (2018) in chickpea.
 
Number of branches/ plant
 
Seed priming with 1.0% potassium nitrate (13:00:45) for 4 hours recorded significantly more number of branches/ plant (6.82 branches/ plant) than the control (5.03 branches/ plant) and seed priming with normal water for 4 hours (5.77 branches/ plant). However, it was at par with all other seed priming treatments. Similar increase in number of branches was reported by Harris et al., (1999) in chickpea crop.
 
Number of pods and grain yield/ plant
 
Seed priming with 1.0% potassium nitrate for 4 hours recorded significantly more number of pods/plant (38.43 pods/ plant) than the rest of the treatments but it was on par with seed priming with 0.5% potassium nitrate for 4 hours (36.95 pods/plant). Seed priming resulted in increase in pods/plant and the range of increment was 19 to 44% over control treatment. Seed priming with 1.0% potassium nitrate recorded 44% more pods than the control treatment.
       
Seed priming with 1.0% potassium nitrate (13:00:45) for 4 hours recorded significantly more grain yield/plant (9.43 g/plant) than the rest of the treatments but it was on par with seed priming with 0.5% potassium nitrate for 4 hours (9.34 g/plant), seed priming with 1.0% urea for 4 hours (8.78 g/plant), seed priming with 1.0% Ammonium sulphate for 4 hours (9.22 g/plant) and seed priming with GA₃ 50 ppm for 4 hours (9.20 g/plant). The number of pods per plant is an important character which directly influence the yield of the crop. The higher number of pods in seed priming treatment over control (no seed priming) might be due to the fact that primed seeds established earlier than non-primed seeds and the plants attained the vegetative and reproductive stage earlier and at proper time and plants with a greater number of branches and height resulted in higher number of pods and grain yield per plant. Similar observations were reported by Mussa et al., (2001) and Malviya et al., (2010).
 
Seed index
 
Effect of various seed priming treatments on the seed index of chickpea was found to be non-significant (Table 4). However, seed priming with 0.5% potassium nitrate (13:00:45) for 4 hours recorded numerically higher seed index (24.49 g). Whereas, the lowest seed index was observed with the control treatment (23.56 g). The higher seed index recorded in seed primed with 0.5% potassium nitrate over control might be due to their major roles in seed formation and development which is responsible in better translocation of sugar from source to sink in chickpea. Similar observations by Harris et al., (1999) and Kaya et al., (2010) in chickpea.
 

 
Grain, straw yield (kg/ ha) and harvest index
 
Seed priming with 1.0% potassium nitrate for 4 hours recorded significantly higher grain yield (1937 kg/ ha) than the rest of the treatments (Table 4) but it was on par with seed priming with 0.5% potassium nitrate (13:00:45) for 4 hours (1878 kg/ha) and seed priming with 1.0% urea for 4 hours (1800 kg/ha). However, Seed priming with 1.0% potassium nitrate recorded 35% more grain yield than the control treatment. Whereas, the treatment seed priming with 0.5% potassium nitrate and 1% urea, respectively recorded 32 and 26% more grain yield than the control treatment.
       
Seed priming with 1.0% potassium nitrate for 4 hours recorded significantly higher straw yield (2821 kg/ha) than the rest of the treatments (Table 4) but it was on par with seed priming with 0.5% potassium nitrate for 4 hours (2780 kg/ha), 1.0% urea for 4 hours (2694 kg/ha), 1.0% ammonium sulphate for 4 hours (2599 kg/ha), GA₃ 50 ppm for 4 hours (2702 kg/ha) and seed priming with GA₃ 100 ppm for 4 hours (2580 kg/ha).
       
It could be attributed due to advanced metabolic processes and leading to increased growth and yield attributes of chickpea with the treatments seed priming with potassium nitrate and 0.5% urea and improved the plant population, plant height and branches hence formation of more pods/ plant, grain yield/ plant ultimately resulted in higher grain and straw yield. Similar results were also found by Golenzani et al., (2012), Mehari (2015) and Shinde and Hunje (2020). Hence study indicated, the beneficial effect of potassium nitrate over dry seeds in terms of yield.
       
Effect of various seed priming treatments on the harvest index of chickpea was found to be non-significant (Table 4).
 
Effect of seed priming on economics of chickpea production
 
Seed priming with 1.0% potassium nitrate for 4 hours recorded significantly higher gross and net monetary returns (₹  94411 and ₹ 69923/ha GMR and NMR, respectively) than the rest of the treatments (Table 5) but it was on par with seed priming with 0.5% potassium nitrate for 4 hours (₹ 91554 and ₹ 67665/ha GMR and NMR, respectively) and seed priming with 1.0% urea for 4 hours (₹ 87744 and ₹ 63842/ha GMR and NMR, respectively).
 

       
Seed priming with 1.0% potassium nitrate for 4 hours recorded significantly higher B:C ratio (3.80). The lowest B:C ratio was observed with control treatment (3.01). Increased yield owing to seed priming significantly increased the gross and net monetary returns.

On the basis of four years experimentation it can be concluded that, seed priming improved the initial and final plant population, growth and yield contributing parameters in chickpea crop. Seed priming with potassium nitrate for 4 hours helped to boost up the grain yield of rainfed chickpea crop. It has also aided to increase the gross and net income from the rainfed chickpea crop. Considering the benefits of this practice, it needs to be implemented on the larger scale in rainfed chickpea growing areas.