Fiber quality, yield and economic evaluation of Bt cotton hybrids under high density planting under drip irrigation

Introduction

Cotton (Gossypium hirsutum L.) is the most important crop in India and plays a significant role in agriculture and industry worldwide. As per data from the USDA, for the year 2024-25, the expected area under cotton cultivation is 31.1 million hectares and the production is 117.40 million bales, each weighing 217.72 kg. China is largely producing 28.20 lakh bales, India 25 million bales, Brazil 16.90 million bales, the United States 14.30 million bales, and Pakistan 5.50 million bales. Among the states, Maharashtra is the highest producer with 84.80 lakh bales followed by Gujarat (80.01 lakh bales), Telangana (48.95 lakh bales), Rajasthan (20.42 lakh bales) and Karnataka (18.56 lakh bales). The area under cotton for 2024-25 is 112.94 lakh hectares, which is less than the 123.70 lakh hectares covered in 2023-24. Maharashtra occupied the maximum cotton area with 40.86 lakh hectares, followed by Gujarat (23.66 lakh hectares), Telangana (17.70 lakh hectares), Karnataka (6.84 lakh hectares) and Madhya Pradesh (6.14 lakh hectares). The study aims to evaluate fiber quality, yield performance and economic returns of different Bt cotton hybrids under high density planting with drip irrigation. Recent studies on high density planting under drip systems in Maharashtra have reported significant increases in seed cotton yield and economic returns, yet comprehensive evaluation of fiber quality traits under these integrated practices remains scarce. Therefore, this study was designed to evaluate the combined effects of high density planting and drip irrigation on fiber quality, yield components, and economic viability of Bt cotton in Maharashtra's agro-ecology, filling the current research gap and providing practical recommendations for sustainable cotton production.

Materials and Methods

The field experiment was conducted at the Cotton Research Farm, Dr. Panjabrao Deshmukh

Results and Discussion

Effect on fiber quality parameters The numerically higher UHML was observed in AKHH 2022-1 Bt (29.8 mm) followed by RCH-971 BG-2 (29.6 mm), whereas SWCH-4823 BG-2 recorded comparatively lower UHML (29.3 mm). Micronaire ranged from 5.0-5.6 μg inch⁻¹, falling within the acceptable range for spinning and indicative of a medium-to-coarse fiber category (Bradow and Davidonis, 2000) [2] . Tenacity values varied from 28.4 to 29.2 g tex⁻¹, with AKHH 2022-1 Bt registering the highest fiber strength. Elongation percentage did not show a marked variation (5.6-5.7%), indicating consistency of fiber maturity among cultivars. Uniformity index ranged from 84.5-84.8%, suggesting well-balanced fiber length distribution, which is desirable for rotor and ring spinning operations (Basal and Tiftik, 2007) [1] . The fiber quality is genetic character and there were major difference in fiber quality of cotton due to different Bt hybrids under various planting geometry. The tested Bt cotton hybrids did not differ significantly with respect to Upper Half Mean Length (UHML), micronaire, tenacity, elongation and uniformity index. Similarly plant spacings did not exert a significant influence on quality parameters UHML remained statistically similar (29.5-29.7 mm), while micronaire ranged between 5.2-5.5 μg inch⁻¹ across all spacing treatments. The 90 cm × 45 cm spacing recorded numerically higher UHML (29.7 mm), whereas 90 cm × 15 cm recorded slightly higher tenacity (29.1 g tex⁻¹) and elongation (5.7%). Uniformity index values remained within a narrow range (84.5-84.8%). Similar results were reported by Reddy and Kumar (2010) [8] . The interaction effect of hybrid and spacing was non-significant for all fiber quality parameters (Table 1). The interaction effect among Bt cotton hybrids and different plant geometry were found to be non-significant. Effect on yield: Bt cotton hybrid AKHH 2022-1 recorded significantly higher seed cotton yield (3134 kg ha -1 ), which was significantly superior to the other two hybrids. This was followed by RCH-971 BG-2 (2928 kg ha -1 ), while the lowest seed cotton yield was noted with SWCH 4823 BG-2 (2787 kg ha -1 ). The higher productivity of AKHH 2022-1 Bt could be attributed to its greater plant vigour, higher yield attributes and higher dry matter partitioning towards economic yield. Similar results were reported by Singh et al. [7,9,6] . Plant geometry significantly influenced seed cotton yield. Closer plant spacing of 90 cm x 15 cm (3435 kg ha -1 ) topped in rank compared to wider spacing of 90 cm x 30 cm (2899 kg ha -1 ) and 90 cm x 45 cm (2514 kg ha -1 ), indicating better utilization of space and higher plant population under highdensity planting. Similar results were found by Solanki et al.

(2020) and Gouthami et al. (2023) [10,3] (Table 2). Bt hybrid AKHH 2022-1 sown at denser plant spacing of 90 cm x 15 cm noted significantly higher seed cotton yield (3744 kg ha - 1 ) and lint yield (1392 kg ha -1 ) over rest of treatment combinations (Table 3 and4).

Effect on Economics

Among the treatments, AKHH 2022- [4,5] . The interaction was found to be significant only for net monetary returns. The treatment combination AKHH 2022-1 Bt sown at denser planting of 90 cm x 15 cm registered higher NMR of Rs.1,82,106 ha -1 over rest of treatment combination (Table 5).

Conclusion

The study found that fiber quality (UHML, micronair value, tenacity, elongation% and uniformity index%) were numerically higher with Bt hybrid AKHH 2022-1 Bt and denser spacing of 90 cm x 15 cm. Bt cotton hybrids and plant geometry significantly influenced yield and economics of Bt cotton under high density planting system (HDPS) with drip irrigation. Among the hybrids, AKHH 2022-1 Bt exhibited superior performance in terms of seed cotton yield and lint yield, which resulted in higher GMR, NMR and B:C ratio compared to the other hybrids. Similar kind of results observed in closer spacing of 90 cm × 15 cm enhanced seed cotton yield on a per hectare basis due to higher plant population, thereby achieving the highest GMR and NMR. Among interactions AKHH 2022-1 Bt with 90 cm x 15 cm spacing recorded the maximum productivity and profitability, proving its suitability for high density planting systems. Thus, adoption of AKHH 2022-1 Bt at a spacing of 90 cm x 15 cm under drip irrigation is the most effective strategy to maximize yield and economic returns of Bt cotton hybrids.

References

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