Evaluation of promising sugarcane genotypes under differential irrigation regimes

Introduction

Sugarcane is one of the world's most important commercial crops, contributing significantly to sugar, ethanol, and bioenergy production. India is the world's second-largest producer of sugarcane after Brazil and plays a vital role in the global sugar industry. The states of Uttar Pradesh, Maharashtra, and Karnataka together contribute more than 80% of the country's total sugar production. Sugarcane is a C₄ crop, and drought is one of the major abiotic stresses limiting its productivity. Increasing water scarcity, climate change, and erratic rainfall have intensified drought stress in sugarcane-growing regions. Water deficit during critical growth stages adversely affects plant growth, photosynthesis, cane yield, and sucrose accumulation, resulting in significant yield losses. Developing drought-tolerant sugarcane varieties is an effective strategy for sustaining productivity under water-limited conditions. Drought tolerance is governed by several morphological, physiological, and biochemical mechanisms, including efficient root development, osmotic adjustment, regulation of stomatal conductance, and improved water-use efficiency. Furthermore, the selection of suitable cultivars, together with appropriate crop management practices, plays a crucial role in reducing drought-induced yield losses. Therefore, the present study was undertaken to evaluate the performance of different sugarcane varieties under drought stress by assessing their growth, physiological, and yield attributes. The findings will aid in identifying drought-tolerant genotypes and support varietal improvement programmers for sustainable sugarcane production under water-limited environments.

Materials and Methods

The present investigation entitled "Evaluation of Promising Sugarcane Genotypes under Differential Irrigation Regimes" was carried out during 2022-23 to 2024-25 at the Research and Development Farm, Vasantdada Sugar Institute, Manjari (Bk.), Pune, Maharashtra, India. The experimental site is located at 18°31′34.32″ N latitude and 73°58′28.56″ E longitude, with an altitude of 190 m above mean sea level. The soil of the experimental field was classified as medium deep black soil having an alkaline reaction (pH 8. The crop was planted at a wider row spacing of 135 cm following the recommended package of practices for Suru sugarcane. A recommended fertilizer dose of 250:115:115 NPK kg ha -¹ was applied. Nitrogen was applied in four equal splits, whereas phosphorus (P₂O₅) and potassium (K₂O) were applied in two equal splits, with 50 per cent at planting and the remaining 50 per cent at the final earthing-up. All the observations recorded during the course of investigation will be subjected to analysis of variance (ANOVA) appropriate for a strip plot design as per Fisher's method.

Results and Discussion

Effect of Irrigation regimes

The data pertaining to tiller count, number of millable canes, cane yield, CCS yield, growth and yield attributes, juice quality and physiological attributes as influenced by different irrigation levels are presented in Fig. 123and Tables 12345. The pooled data revealed that irrigation levels significantly influenced most of the growth, physiological and yield parameters, whereas juice quality parameters remained non-significant. Irrigation at 1.0 IW/CPE ratio (I₂) recorded significantly higher tiller count (104.87 and 85.29 thousand ha -¹) at 120 and 150 DAP, respectively, while the effect at 90 DAP was non-significant. Likewise, irrigation at 1.0 IW/CPE ratio produced significantly higher number of millable canes (74.14 thousand ha -¹), cane yield (134.59 t ha -¹) and CCS yield (21.15 t ha -¹) than irrigation at 0.3 IW/CPE ratio (I₁). The higher tiller population, millable cane number and yield under adequate irrigation may be attributed to improved soil moisture availability, enhanced nutrient uptake and photosynthetic activity. Similar findings were reported by Patil et al. (2023) [14] and Biradar et al. (2023) [2] . Growth and yield attributes were also significantly influenced by irrigation levels. Irrigation at 1.0 IW/CPE ratio recorded significantly higher number of internodes (25.42), internodal girth (10.76 cm), millable cane height (283.66 cm) and single cane weight (1.90 kg). These improvements may be attributed to better moisture availability, nutrient uptake and plant growth. Similar findings were reported by Patil et al. (2023) [14] and Mohan Naik et al. (2020) [12] . The pooled data indicated that irrigation levels did not significantly influence juice quality parameters, viz., brix, sucrose, purity and CCS per cent. The non-significant response may be due to the greater influence of varietal characteristics and crop maturity on juice quality than irrigation treatments. Similar observations were reported by Patil et al. (2023) [14] . Among the physiological attributes, irrigation at 1.0 IW/CPE ratio recorded significantly higher leaf area index (1.25 and 1.73 at 150 and 200 DAP, respectively) and root dry weight (27.89 g clump⁻¹ at 200 DAP). However, significantly higher dry matter accumulation at harvest (1099.11 g clump -¹) was recorded under irrigation at 1.0 IW/CPE ratio.

Effect of genotypes

The pooled data presented in Fig1to 3 and Tables 1 to 5 revealed that sugarcane genotypes significantly influenced tiller count, number of millable canes, cane yield, CCS yield, growth and yield attributes, juice quality, leaf area index and root dry weight, whereas specific leaf weight and dry matter accumulation remained non-significant at most of the growth stages. Among the genotypes, CoM 09057 recorded the highest tiller count at 90 DAP (71.17 thousand ha⁻¹), whereas VSI 21121 at 120 and 150 DAP (107.44 and 94.28 thousand ha⁻¹, respectively). The higher tiller production observed in these genotypes may be attributed to their superior genetic potential, early vigour, efficient utilization of available resources, and better adaptability to the prevailing environmental conditions. Similarly, VSI 21121 recorded the maximum number of millable canes (82.72 thousand ha⁻¹). The higher number of millable canes in this genotype could be due to improved tiller survival, reduced mortality of shoots during the grand growth phase, and its inherent genetic capacity to retain productive tillers until harvest. Since the number of millable canes is largely determined by tiller production and survival, the superior performance of VSI 21121 in these traits ultimately resulted in a higher millable cane population. Similar findings were reported by Vasantha et al. (2005) [17] , Salim et al. (2021) [15] , and Patil et al. (2023) [14] . Genotype VSI 21121 recorded the highest cane yield (137.34 t ha⁻¹), whereas MS 10001 recorded the highest CCS yield (20.97 t ha⁻¹). The superior yield performance may be due to higher millable cane population and better growth attributes. Similar results were reported by Vasantha et al. (2005) [17] , Naidu and Venkataramana (1989) [13] and Patil et al. (2023) [14] . Among growth and yield attributes, CoVSI 9805 recorded maximum internodal girth (11.11 [11] and Vasantha et al. (2005) [17] . Physiological parameters also varied among genotypes. Co 12009 recorded higher leaf area index (0.23 and 1.79 at 50 and 200 DAP, respectively) and root dry weight (20.63 and 28.66 g clump⁻¹ at 150 and 200 DAP), whereas VSI 21121 recorded higher dry matter accumulation (35.52 g clump⁻¹) at 50 DAP. These variations may be attributed to differences in canopy development, root growth and genetic adaptability. Similar findings were reported by Salim et al. (2021) [15] and Patil et al. (2023) [14] .

Interaction effect

The interaction effect between irrigation levels and genotypes was non-significant for growth and yield attributes as well as juice quality parameters. However, root dry weight at 200 DAP was significantly influenced by the interaction effect. Under 0.3 IW/CPE ratio, the genotypes VSI 21121 and Co 12009 recorded significantly higher root dry weight of 26.34 and 26.33 g clump⁻¹, respectively. Similarly, under 1.0 IW/CPE ratio, same genotypes performed better.

Acknowledgement

AcknowledgementWe are thankful to Mr. Sambhaji Kadupatil, Director General, Vasantdada Sugar Institute, Pune for his encouragement during this research work and giving permission to publish this article. Authors are also thankful to scientists and supporting staff of crop production division for their help during the field experimentation.

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