Yield Response of Maize Hybrids on Different Spacing Patterns under Irrigated Areas of Punjab

Maize, popularly called “Queen of Cereals,” is a crop of vital international importance from various points of view, such as adaptability, food value and multipurpose applications. This crop originated in Central America and has been a staple for agricultural systems all over the world, far from just the regions of origin, but remains most important for world food security (Kaushal et al., 2023). The genetic diversity and ability of maize to grow under diverse agroclimatic conditions make it an equally indispensable crop for developed and developing countries. Maize grows well on a variety of environments, from arid to semi-arid zones to sub-humid and tropical areas (Tiwari and Yadav, 2019). Maize is a key crop in agriculture all over the world, providing a crucial basis of food security, industrial applications and economic sustainability (Tanumihardjo et al., 2020). In terms of importance, it is ranked third, after wheat and rice and over time has grown to be an essential food for millions. In India, maize is placed very importantly, being considered the third of all cereals and cultivated in an area of greater significance, mainly during the kharif, about 82% of the area sown to this crop (Muramatti, 2023). However, due to favourable climatic conditions, lesser biotic stresses and assured irrigation, the highest productivity is obtained in the rabi season. Despite being important, the average productivity of maize in India is very much lower than that at the global level, suggesting a wide gap that, under present-day circumstances, would require adoption of some innovative agronomic practices and technological interventions (Ram et al., 2023).
       
The 2^nd advance estimates for the year 2023-24 state that maize crop has been estimated as 376.65 lakh tones, as compared to 380.85 lakh tones in 2022-23. The area of maize in India for 2023-24 broadly covers 23.72 lakh hectares. The predominant maize growing states in India are Bihar, Maharashtra, Tamil Nadu, Telangana, West Bengal and Gujarat (Anonymous, 2024). Maize diversity in cultivation in India ranges between both traditional and emerging maize-growing states (Murdia et al., 2016). Longtime traditional states like Madhya Pradesh, Rajasthan and Uttar Pradesh have been predominant in maize cultivation for many decades; however, nontraditional states like Andhra Pradesh and Karnataka have turned out to be major contributors in the last couple of decades or so (Pavithra et al., 2018). Also, there has been an increasing dimension that is spring maize, particularly in the northern states of Uttar Pradesh, Haryana and Punjab regarding maize farming in India. In addition to diversifying cropping systems, spring maize opens up opportunities for residual soil moisture and land use optimization during an otherwise lean agricultural period (Layek et al., 2018). It points towards the dynamic role that maize production generates in India for its ability to smoothen agricultural and economic disbalances on the given regional basis (Erenstein et al., 2022).
       
Despite steady growth, the average maize productivity in India stands at about 2,965 kg/ha, substantially below the world average. This is attributed to the dominance of rainfed conditions, less than optimal agronomic practices and other factors, such as pest infestations and nutrient imbalance. The driving force in alleviating this gap in productivity will therefore be the use of improved maize hybrids with suitable agronomic practices and the application of modern technology. Together, maize varieties and plant spacing provide means of optimizing resource-efficient growth and yield (Wani et al., 2021). The hybrid maize varieties also have different responses to spacing due to genetic diversity and physiological traits. Correct spacing will determine light interception, air circulation, root development and nutrient uptake, thus determining the overall architecture of the plant and biomass accumulation. It has been reported in several studies that the appropriate spacing pattern utilizes all available resources and maximizes production without substantial internal competition among plants. For example, more room for plant growth (60 cm x 20 cm) would support bigger cobs; however, while grain weight without resource competition may increase with lower density spacing, the increase in population and biomass per plant is much greater under denser populations. On the flip side, close spacing may increase shading and limit light availability, posing potential threats to pest and disease outbreak (Bulungu, 2012).
       
Maize hybrids significantly boost crop yield, resilience and profitability. They offer improved resistance to pests, diseases and environmental stresses. By enhancing uniformity and maturity rates, hybrids support mechanized farming and food security. Their adoption has revolutionized modern agriculture, especially in developing regions, by increasing productivity and reducing farming risks. Satisfactory spacing maximizes the balancing of productive attributes with resource usage, thereby increasing the productivity and profitability. Scientific evidence shows that increased spacing between plants enhances the growth parameters of plant height, cob size and grain weight (Ali et al., 2017). According to Vijayalakshmi et al. (2020), spacing among others is an important factor involved in improving resource use efficiency associated with water and nutrients for productivity in different environments (Testa et al., 2016).

The current study was conducted at the Lovely Professional University Agriculture Research Farm, Phagwara (Punjab), during two consecutive kharif seasons of 2022 and 2023. The crops are sown on the mid of June for the consecutive years and harvested 95 DAS. The research farm is situated at a latitude of 31^o.14' N and longitude of 75^o.42'  E and an altitude of 247.52 m above mean sea level. A field of research farm having homogeneous fertility and uniform textural make-up was selected for the field experimentation. Being the region of Punjab, it usually experiences subtropical climate conditions-seasons categorized as summer, monsoon and winter. The monsoon season further sets in by the first week of July and stays through August mid, when rainfall is usually recorded as 730 mm from the south-west monsoon currents and comes in heavy showers mainly within the months of July and August. The presence of cold temperature characterizes winter, which comes in late November and lasts to February, with January usually showing the lowest temperatures. The winter and pre-monsoon summer retain a dry climate. After the harvest of previous crop, the land was ploughed once with mould board plough. Soil was brought to fine tilth by crushing the clods and harrowing two times, later the land was smoothened with wooden plank. Recommended doses of fertilizers were 80 kg N, 40 kg P₂O₅ and 40 kg K₂O per ha. And the full dose of P and K and half dose of N were applied through urea, single super phosphate and muriate of potash at the time of sowing and remaining half dose of N was applied after 25-30 DAP. The seeds were treated with thirum. Seed was sown at 3-4 cm depth and covered with soil. Sowing was done on last week of June, 2022 and 2023 by dibbling 2 seeds per hill. Seeds were sown as per spacing treatments in each plot. To protect the crop from stem borer infestation the granular application of Carbofuran 3% GR was done after 47 DAS. Spraying of Chlorpyriphos 25 EC at the concentration of 0.01% was undertaken at 70 DAS to protect the crop from corn borer. Use 30 kg seed per acre.
 
Treatment details
 
The hybrid varieties which were used in this experiment are AHC-2033-the first yellow seeded early maturing hybrid maize variety which is earlier by 15 days in milking, P1899- The plants of this hybrid variety are tall with broad leaves. Its’ ear placement is medium. Ears are long, thick and cylindrical. Grains are white, bold and semi flint to semi dent. It is moderately resistant to leaf blight. Its’ average green fodder yield is about 150 quintal per acre and NHM-589- Its’ plants are tall, vigorous and narrow leaved. It is moderately resistant to brown stripe downy mildew diseases. Its’ ear placement is medium. Ears are short, thick and cylindrical. The grains are white and bold. It yields about 148 quintal of green fodder per acre. We proceeded this experiment with four different spacings: 60 cm x 25 cm, 70 cm x 20 cm, 70 cm x 30 cm and 70 cm x 25 cm.

Number of cobs per plant
 
The number of cobs per plant was significantly influenced by maize varieties and spacing patterns during both years and in the pooled analysis and data are presented in Table 1. Among the varieties, V2 (P-1899) consistently recorded the highest number of cobs per plant, with 1.46 in 2022-23, 1.49 in 2023-24 and 1.48 in pooled results. This was followed by V1 (AHC-233), which revealed 1.40 cobs per plant in 2022-23, 1.43 in 2023-24 and 1.41 in pooled data. The lowest number of cobs per plant was observed in V3 (NHM-589), which recorded 1.31 in 2022-23, 1.33 in 2023-24 and 1.32 in pooled basis. The spacing patterns also significantly affected the number of cobs per plant. The S4 (70 cm x 25 cm) produced the highest number of cobs per plant with 1.58 in 2022-23, 1.60 in 2023-24 and pooled of 1.59. However, S4 was followed by S2 (70 cm x 20 cm), with values of 1.51, 1.54 and 1.53 at 2022, 2023 and pooled of both years, respectively, while the lowest number of cobs per plant was observed in S1 (60 cm x 25 cm), with pooled values of 1.15. The wider spacing in S4 likely facilitated better resource availability, resulting in enhanced cob formation. Results are corroborated with Azam et al., (2007) and Mathukiya et al., (2014).


 
Length of cob     
 
Cob length demonstrated a significant influence of both variety and spacing (Table 1). Among the varieties, V2 (P-1899) resulted the longest cob length with 19.65 cm in 2022-23, 19.72 cm in 2023-24 and pooled of 19.68 cm. This was followed by V1 (AHC-233), which recorded values of 19.29 cm in 2022-23, 19.35 cm in 2023-24 and pooled value of 19.32 cm. The shortest cob length was observed in V3 (NHM-589), with pooled values of 18.31 cm. Spacing patterns had a pronounced effect on cob length during the experimentation. The S4 (70 cm x 25 cm) produced the longest cobs, with values of 20.64 cm in 2022-23, 20.69 cm in 2023-24 and pooled value of 20.66 cm. This was followed by S2 (70 cm x 20 cm), which recorded pooled values of 20.12 cm, while the shortest cobs were observed in S1 (60 cm x 25 cm), with pooled values of 17.28 cm. The longer cob lengths under wider spacing in S4 can be attributed to reduced competition for light, nutrients and water, allowing for better cob development, these results are corroborated with Mathukiya et al., (2014) and Hasan et al., (2018).
 
Number of grain rows per cob
 
The data related to number of grain rows per cob presented in Table 2 was significantly influenced by maize varieties and spacing patterns during both years and pooled analysis. Among the varieties, V2 (P-1899) recorded the highest number of grain rows per cob, with values of 13.32 in 2022-23, 13.40 in 2023-24 and pooled of 13.36. The V2 was followed by V1 (AHC-233) with pooled values of 13.08, while V3 (NHM-589) recorded the lowest (12.59) during the experimentation. These results highlight the superior productivity potential of V2 in terms of cob row formation. Spacing patterns also significantly affected the number of grain rows per cob during the experimentation. The S4 (70 cm x 25 cm) revealed the highest number of grain rows per cob, with 13.93 in 2022-23, 14.02 in 2023-24 and pooled of 13.98 followed by S2 (70 cm x 20 cm) with pooled values of 13.57. The lowest number of rows per cob was recorded in S1 (60 cm x 25 cm) (11.72). Wider spacing (S4) likely provided favourable growing conditions for improved grain row development, corroborated with the results of Antony et al., (2024).
 
Number of grains per row
       
The number of grains per row was significantly influenced by maize varieties and spacing patterns during both years and in the pooled analysis and data presented in Table 2. Among the varieties, V2 (P-1899) recorded the highest number of grains per row, with values of 19.38 in 2022-23, 19.43 in 2023-24 and a pooled value of 19.41 and it was followed by V1 (AHC-233) with pooled values of 19.08, while V3 (NHM-589) recorded the lowest with pooled values of 17.64. Spacing patterns significantly affected the number of grains per row during the investigation. The S4 (70 cm x 25 cm) revealed the maximum number of grains per row (20.72) followed by S2 (70 cm x 20 cm) (20.01) based on the pooled of both years. The lowest number of grains per row (16.21) was observed in S1 (60 cm x 25 cm). The increased number of grains per row in wider spacing treatments like S4 can be attributed to reduced interplant competition, positively correlated with Biswas et al., (2014) and Jithendra et al., (2013).


 
Number of grains per cob
 
The number of grains per cob was significantly influenced by maize varieties and spacing patterns during both years and in the pooled analysis (Table 2). Among the varieties, V2 (P-1899) recorded the highest number of grains per cob i.e., 259.92 in 2022-23, 262.12 in 2023-24 and a pooled value of 261.02. However, V2 was followed by V1 (AHC-233) with the pooled value of 251.36, while V3 (NHM-589) recorded the lowest (223.06) during the investigation. Spacing patterns had a significant effect on the number of grains per cob during the experimentation. The S4 (70 cm x 25 cm) exhibited the highest number of grains per cob, with pooled values of 290.03, followed by S2 (70 cm x 20 cm) (271.81). While, the lowest number of grains per cob was observed in S1 (60 cm x 25 cm) (190.08). The wider spacing in S4 provided plants with better access to resources, allowing for more grain development per cob, correlated with the results of Biswas et al., (2014) and Niveditha and Nagavani (2016).
 
Grain yield
 
Grain yield was significantly influenced by maize varieties and spacing patterns during both years and in the pooled analysis and related data are presented in Table 3. Among the varieties, V2 (P-1899) recorded the highest grain yield i.e., 157.47 q/ha in 2022-23, 161.96 q/ha in 2023-24 and 159.71 q/ha of pooled of both years. This was followed by V1 (AHC-233) recorded pooled grain yield of 150.92 q/ha. While, V3 (NHM-589) recorded the lowest grain yield (136.81 q/ha) as per pooled of both the years. The superior performance of V2 may be attributed to its higher productivity potential, as reflected in the better cob parameters and grain yields. Spacing patterns significantly influenced grain yield as well during the experimentation. The S2 (70 cm x 20 cm) produced the highest grain yield i.e., 193.44 q/ha in 2022-23, 198.00 q/ha in 2023-24 and pooled of 195.72 q/ha. However, S2 followed by S4 (70 cm x 25 cm) and observed grain yield of 166.49 q/ha based on pooled of both years. While, the lowest grain yield was recorded in S3 (70 cm x 30 cm) with pooled values of 109.62 q/ha. The higher grain yield in S2 can be attributed to optimal plant density, which allowed for efficient resource utilization. The results are corroborated with Lashkari et al., (2011), Khalil et al., (2011) and Magar et al., (2021).  


 
Straw yield (q/ha)
 
The data related to straw yield are presented in Table 3 and varied significantly among maize varieties and spacing patterns during both years and in the pooled analysis. Among the varieties, V2 (P-1899) recorded the highest straw yield i.e., 158.82 q/ha in 2022-23, 159.96 q/ha in 2023-24 and pooled of 159.39 q/ha. V2 treatment was followed by V1 (AHC-233), which recorded a pooled straw yield of 155.14 q/ha. While, V3 (NHM-589) recorded the lowest straw yield with pooled values of 146.23 q/ha. The higher straw yield in V2 reflects its superior vegetative growth and biomass production. Spacing patterns also significantly influenced straw yield during the investigation. The S2 (70 cm x 20 cm) exhibited the highest straw yield i.e., 191.93 q/ha in 2022-23, 192.99 q/ha in 2023-24 and pooled of 192.46 q/ha. The S4 (70 cm x 25 cm) treatment followed S2 with pooled straw yield of 162.84 q/ha. While, the lowest straw yield was recorded in S3 (70 cm x 30 cm) with pooled values of 114.84 q/ha. The higher straw yield in S2 can be attributed to its optimal spacing, which resulted in enhanced biomass accumulation. These results are correlated with the results of Mekuanint et al., (2018) and Reddy et al., (2020).
 
Economics
 
Table 4 assesses the performance of three maize varieties (V1, V2 and V3) and four spacing treatments (S1 to S4) over two consecutive years (2022 and 2023). Grain output, gross and net realisation and benefit-cost ratios (BCR) were highest for V2, which yielded the best results for all the measures of performance and economic outcome. V1 was second for both measures, while V3 was always worst. S2 (widest spacing) was the better of the spacing, with the highest stover and grain yields and significantly high BCRs of 10.09 and 9.85 respectively in 2022 and 2023. This would have likely correlated with better light interception, increased amount of food and less plant-plant competition. For S3 with the tightest spacing, results were worse. The results provide important information for improving crop management techniques and resource use efficiency, indicating that the V2 and S2 spacing combination is ideal for optimising maize yield and profitability under the conditions under study.

The results highlight the importance of variety and spacing interactions in determining how well maize parameters work. The best variety was P-1899 (V2), particularly when spaced at S4 (70 cm x 25 cm), which continuously produced better results for all attributes measured, such as cob length, cob number, grain rows and grain count. Crop performance was improved by wider spacing because it made resource allocation easier and decreased competition. Closer spacing (S1 and S2) and NHM-589 (V3), on the other hand, were less advantageous and limited the total yield components.

The authors are grateful to Lovely Professional University, Punjab for providing research support and laboratory facilities during this study.
 
Disclaimers
 
The opinions and findings articulated in this article are exclusively those of the writers and do not always reflect the perspectives of their connected institutions. The writers bear responsibility for the truth and completeness of the material presented; nevertheless, they disclaim all duty for direct or indirect damages arising from the use of this content.