Evaluation and diversity analysis for growth, yield and quality traits in okra [Abelmoschus esculentus (L.) Moench] genotypes

Introduction

Okra (Abelmoschus esculentus L. Moench) is an important warm-season vegetable crop belonging to the family Malvaceae. It is a herbaceous annual plant, propagated by seeds, with a chromosome number reported as 2𝑛 = 72-144. It is widely cultivated in tropical and subtropical regions and is valued for its nutritional, medicinal, market and export potential. India is the leading producer of okra globally (Anon., 2022). Despite its importance, okra production is affected by several insect pests and diseases, particularly yellow vein mosaic virus, which reduces yield and fruit quality. Hence, improvement of traits such as earliness, branching, number of fruits per plant, fruit quality, pest and disease resistance and yield is essential. Variation among the available genotypes forms the basic requirement for crop improvement, as it provides the raw material for identifying and selecting genotypes possessing desirable traits. Analysis of variance helps establish whether genuine and exploitable differences exist among genotypes for a given character, while the mean performance of genotypes for growth, flowering, yield and quality traits indicates which genotypes are best suited for direct cultivation or for use as parents in hybridization programmes. However, variability alone is not sufficient to ensure success in a breeding programme, the genetic divergence among genotypes must also be assessed, since hybridization between genetically diverse parents is more likely to produce heterotic combinations and desirable transgressive segregants in the resulting progeny. Multivariate clustering techniques enable genotypes to be grouped on the basis of their overall genetic similarity, allowing breeders to select divergent parents from different clusters rather than relying on geographic origin or phenotypic similarity alone, both of which are often poor indicators of true genetic distance.

Therefore, the present study was undertaken to assess the analysis of variance, mean performance and genetic divergence of twenty-two okra genotypes, along with two check varieties, for growth, flowering, yield and quality traits, with a view to identifying superior genotypes for direct cultivation as well as genetically diverse parents suitable for hybridization and improvement programmes in the region.

Material and methods

The present investigation was carried out at the Zonal Agricultural and Horticultural Research Station (ZAHRS), Shivamogga, during summer 2025-26. The experimental site is located between 13° 92' N latitude and 75° 56' E longitude at an elevation of 640 m above mean sea level, in the Southern Transition Zone (Zone-7) of Karnataka, which experiences a tropical monsoon climate with warm summers, moderate winters and high humidity during the rainy season. The soil of the experimental field was red sandy loam in texture, well-drained and moderately fertile.

Experimental material and design

Twenty-two genotypes of okra, collected from different research institutes and sources across India, were evaluated along with two check varieties (Arka Anamika and Arka Abhay) in a Randomized Complete Block Design (RCBD) with three replications (Table 1). Each genotype was raised in a plot size of 3 m × 1.8 m at a spacing of 60 cm × 45 cm. The recommended dose of fertilizer was applied as per the package of practices of UHS, Bagalkot (Anon., 2013). The crop was irrigated through drip irrigation to compensate 80 per cent evapotranspiration and was kept weed-free by manual weeding. Need-based plant protection measures were followed against sucking pests (aphids, thrips, leafhoppers, whiteflies) and diseases (powdery mildew, Cercospora leaf spot). Five plants were selected randomly from each replication and tagged for recording observations.

Observations recorded and statistical analysis

Growth parameters, viz., plant height (cm), number of leaves per plant, internodal length (cm), number of nodes per plant and stem girth (mm), were recorded. Yield parameters (days to first harvest, fruit length, fruit girth, average fruit weight, number of fruits per plant, fruit yield per plant and yield per plot) were recorded. Quality parameters, viz., leaf and pod total chlorophyll (Arnon, 1949) [1] , total phenol content by the Folin-Ciocalteu method (AOAC, 1990) [2] , carbohydrate content by the phenol-sulphuric acid method (Dubois et al., 1956) [3] , protein content by Lowry's method (Lowry et al., 1951) [4] , total sugars by the anthrone method (Ranganna, 1977) [5] , crude fibre (AOAC, 2005) [6] and mucilage content by hot water extraction method, were estimated. The mean data recorded for each character were subjected to analysis of variance as per the RCBD model suggested by Panse et al. (1967) [7] , and the significance of differences among genotypes was tested using the 'F' test; standard error of mean and critical difference were worked out at 5 per cent probability. Genetic divergence among the genotypes was assessed using the Mahalanobis (1936) [8] D 2 statistic; genotypes were grouped into clusters following Tocher's method (Rao, 1952) [9] , and intra-and inter-cluster distances were computed as per Singh et al. (1977) [10] .

Results and discussion

Analysis of variance

Analysis of variance carried out for growth, flowering, fruit yield and biochemical quality parameters of the twenty-two okra genotypes revealed highly significant differences among the genotypes for almost every character studied, confirming the presence of an exploitable amount of genetic variability among the genotypes evaluated (Table 2). Highly significant differences among genotypes for growth, flowering, yield and quality traits have similarly been reported in okra by Dhall et al. (2001) [11] , Singh et al. (2008) [12] , Sravanthi et al. (2021) [13] and Reddy et al. (2022) [14] , which validates the wide genetic base that is generally exploited in this crop for selection-based improvement.

Mean performance of okra genotypes

The mean performance of the twenty-two okra genotypes for growth, flowering, yield and quality traits, along with their standard error of mean (S. Em ± ) and critical difference (CD) at 5 per cent probability, is discussed. Marked differences were observed among the genotypes for plant height at 120 DAS, values ranging from 96.11 to 118.24 cm with an overall mean of 106.99 cm (Table 3). Kashi Chaman recorded the highest plant height (118.24 cm), followed by Green Star Okra (116.35 cm) and Arka Anamika (116.10 cm), while Kashi Pragati recorded the lowest (96.11 cm); this superior performance of Kashi Chaman throughout the growth period may be attributed to its genetic potential for vigorous vegetative growth and greater internodal elongation, and similar genotypic differences in plant height among okra genotypes were reported by Jaiprakashnarayan et al. (2006) [15] and Awasthi et al. (2022) [16] . Number of leaves per plant at 90 DAS varied from 20.11 to 29.02 with average mean of 25.95 the maximum value was recorded in Green Star Okra (29.02), followed by Purna Kranti (Go-10) (24.90) and Purna Rakshak (Gno-1) (27.22), while Nol-303+ (Julie) recorded the minimum (20.11) (Table 3), a trend of genotypic variation in leaf production also reported by Jaiprakashnarayan et al. (2006) [15] . Internodal length at 120 DAS ranged from 5.39 cm to 8.78 cm with average mean of ICAR-IIHR, Bengaluru 7.04 cm, the highest internodal length recorded in Pusa Sawani (8.78 cm), followed by Okra Green Long (8.39 cm) and Halu Bende (8.10 cm), and the minimum in Kashi Kranti (5.39 cm) (Table 3), similar variation in internodal length among okra genotypes was reported by Awasthi et al. (2022) [16] . Number of nodes at 120 DAS varied from 13.91 to 21.99 with average mean of 17.09, Kashi Pragati recorded the highest (21.99), followed by Indo US Sungreen (19.96) and Green Star Okra (18.63), whereas Pusa Sawani recorded the lowest (13.91) (Table 3), a similar genotypic variation in number of nodes in okra have been reported by Das et al. (2012) [17] . Stem girth at 120 DAS differed significantly among the genotypes, ranging from 47.66 to 71.82 mm with an average mean of 54.21 mm, the maximum stem girth was recorded in Halu Bende (71.82 mm), followed by Okra Tree (69.59 mm) and Prabhani Kranti (58.21 mm), while the minimum was observed in Kashi Kranti (47.66 mm) (Table 3), similar variation in stem girth among okra genotypes have been reported by Jaiprakashnarayan et al. (2006) [15] . The considerable genotypic variation observed for all the growth attributes at 120 DAS indicates good scope for selecting genotypes with vigorous vegetative growth in future okra improvement programmes. Days to 50 per cent flowering ranged from 40.40 to 54.50 days with a mean of 44.59 days (Table 3), where Kashi Chaman (40.40 days) attained 50 per cent flowering earliest, whereas Okra Tree (54.50 days) took the longest, a similar variability among okra genotypes have been reported by Samim et al. (2018) [18] . The considerable variation observed among the genotypes for this trait reflects the presence of genetic diversity and offers good scope for selection of early maturing genotypes. Days to first harvest varied from 41.18 to 58.73 days with average mean of 48.07 days (Table 4), Kashi Pragati (41.18 days) recorded earliest first harvest, whereas Okra Tree (58.73 days) took the maximum number of days, followed by Indo US Sungreen (54.74 days) and Arka Abhay (52.71 days), similar variation in days to first harvest have been reported by Verma et al. (2007) [19] and Adiger et al. (2011) [20] . Average fruit weight ranged from 9.80 g to 20.32 g with average mean of 13.76 g, whereas Halu Bende (20.32 g) recorded the highest fruit weight, followed by Okra Green Long (18.90 g) and Okra Tree (17.10 g), while Purna Rakshak (Gno1) recorded the lowest (9.80 g), similar variation in average fruit weight among okra genotypes have been reported by Das et al. (2012) [17] . Fruit girth varied from 44.94 mm to 116.29 mm with a mean of 60.34 mm, Green Star Okra (116.29 mm) recorded the maximum, followed by Okra Double Colour (110.00 mm) and Halu Bende (97.43 mm), while Nol-303+ (Julie) recorded the minimum (44.94 mm), a similar variation in fruit girth having been reported by Duggi et al. (2013). Fruit length ranged from 9.47 to 19.20 cm with an average mean of 13.27 cm (Table 4), Halu Bende (19.20 cm) recorded the longest fruits, followed by Okra Green Long (17.24 cm), while Kashi Pragati produced the shortest fruits (9.47 cm). Number of fruits per plant ranged from 13.20 to 37.10 with a mean of 24.35 (Table 4), Kashi Pragati (37.10) recorded the maximum, followed by Pusa Bhendi-5 (33.60) and Green Star Okra (29.80), while Halu Bende recorded the minimum (13.20), similar variation having been reported by Das et al. (2012) [17] and Duggi et al. (2013). Fruit yield per plant varied from 272.50 g to 483.50 g with a mean of 362.88 g; Kashi Pragati (483.50 g) recorded the highest, followed by Pusa Bhendi-5 (459.50 g) and Selection-1 (445.50 g), while Pusa Sawani recorded the lowest (272.50 g). Yield per plot ranged from 5.45 kg to 9.67 kg with a mean of 7.26 kg; Kashi Pragati recorded the highest yield per plot (9.67 kg), followed by Pusa Bhendi-5 (9.19 kg) and Selection-1 (8.91 kg), while Pusa Sawani recorded the lowest values (5.45 kg), similar variation in fruit yield among okra genotypes having been reported by Das et al. (2012) [17] and Karadi et al. (2018) [21] . The wide variability recorded for yield and its component traits indicates substantial scope for iden-tifying high-yielding genotypes for direct use or as parents in hybridization. Leaf total chlorophyll content which varied from 1.94 to 3.02 mg g -1 , while pod total chlorophyll content ranged from 1.44 to 2.28 mg g -1 (Table 5), Purna Rakshak (Gno-1) recorded the highest values for both leaf and pod chlorophyll content, followed by Purna Kranti (Go-10) and Nol-303+ (Julie), whereas the lowest chlorophyll content were consistently recorded in Okra Red. Total sugars varied from 1.50 to 3.50 per cent with average mean of 2.35 per cent (Table 5), Halu Bende (3.50 %) recorded the highest, followed by Selection-1 (3.25 %) and Pusa Sawani (3.20 %), while Okra Red recorded the lowest (1.50 %). Carbohydrate content ranged from 22.40 to 42.10 g kg -1 with a mean of 34.27 g kg -1 ; Okra Tree (42.10 g kg -1

) recorded the highest, followed by Kashi Parakram (40.20 g kg -1 ) and Indo US Sungreen (39.50 g kg -1 ), while Okra Red recorded the lowest. Phenol content ranged from 35.80 to 50.20 mg GAE with a mean of 40.71 mg GAE; Okra Red (50.20 mg GAE) recorded the highest, followed by Kashi Lalima (45.56 mg GAE), while Pusa Sawani recorded the lowest (35.80 mg GAE). Protein content varied from 1.77 to 3.10 per cent with a mean of 2.48 per cent; Okra Red (3.10 %) recorded the highest, followed by Kashi Lalima (2.98 %), while Halu Bende recorded the lowest (1.77 %). Crude fibre content ranged from 8.87 to 14.31 g 100 g -1 with a mean of 10.87 g 100 g -1 ; Kashi Parakram (14.31 g 100 g -1

) recorded the highest and Okra Red the lowest (8.87 g 100 g -1

), a similar variation for chlorophyll content, total sugars, carbohydrate content, phenol content, protein content and crude fibre content have been reported by Mohammed et al. (2022) [22] . Mucilage content ranged from 11.33 to 32.21 g kg -1 with a mean of 20.89 g kg -1 ; Halu Bende (32.21 g kg -1 ) recorded the highest, followed by Arka Anamika (30.10 g kg -1 ) and Arka Abhay (29.30 g kg -1

), while Kashi Lalima recorded the lowest (11.33 g kg -1 ), similar variation in mucilage content having been reported by Duggi et al. (2013). The reciprocal trend noted between phenol/protein content and sugar/chlorophyll content across genotypes such as Okra Red and Purna Rakshak (Gno-1) points to differential partitioning of biochemical constituents among the genotypes.

Genetic divergence

Genetic divergence among the twenty-two okra genotypes was assessed using the Mahalanobis D 2 statistic. The genotypes were grouped into five distinct clusters by Tocher's method, Cluster I being the largest with fourteen genotypes, indicating a high degree of genetic similarity among these entries, while the smaller clusters comprised comparatively more diverse genotypes that could be effectively utilised in hybridization programmes (Table 6), this pattern, wherein a majority of genotypes fall into one major cluster while the rest are distributed into smaller, more divergent groups, has similarly been reported in okra by Akotkar et al. (2010) [23] , Pradip et al. (2010) [24] , Shaikh et al. (2013) [25] and Narkhede et al. (2015) [26] , and the predominance of Cluster I suggests a common breeding history among these genotypes, whereas a similar lack of correspondence between genetic divergence and geographic origin was reported by Das et al. (2012) [17] . Principal component analysis revealed that the first five components together accounted for 80.22 per cent of the total variance, with number of fruits per plant contributing predominantly to the first principal component. The maximum intra-cluster distance was recorded in Cluster I (5,705.41), followed by Cluster IV (5,487.87) and Cluster V (4,612.16), while Cluster III, comprising a single genotype, recorded zero intra-cluster distance. Among the inter-cluster distances, the maximum divergence was observed between Cluster III and Cluster V (20,636.75), followed by Cluster II and Cluster V (18,774.02), indicating that genotypes placed in these clusters were the most genetically divergent, while the minimum inter-cluster distance (8,090.03) was recorded between Cluster I and Cluster II, suggesting a comparatively closer genetic relationship (Table 7), similarly wide inter-cluster divergence has been reported in okra by Prakash et al. (2010) [27] ,

Prakash et al. (2011) [28] , Reddy et al. (2012) [29] and Balai et al. (2015) [30] .

Kashi pragati Pusa Bhendi-5 Selection -1

Conclusion

The study revealed highly significant differences among the twentytwo okra genotypes for nearly all growth, flowering, yield and quality traits assessed, indicating substantial and exploitable genetic variability within the germplasm evaluated at ZAHRS, Shivamogga. No single genotype was found to be superior across all traits; rather, distinct genotypes excelled for specific characters -Kashi Chaman for plant height, Okra Tree for leaf number and carbohydrate content, Halu Bende for fruit weight and total sugars, Green Star Okra for fruit girth, and Okra Red for phenol and protein content. With respect to fruit yield per plant and yield per plot -the traits of greatest economic significance to growers-Kashi Pragati, Pusa Bhendi-5 and Selection-1 consistently emerged as the top three performers. These genotypes can be recommended for cultivation in the Southern Transition Zone of Karnataka, as well as for use as parental lines in future okra breeding and hybridization programmes. Cluster analysis based on genetic divergence classified the genotypes into five distinct clusters. Genotypes belonging to the most divergent clusters, namely Clusters II, III and V, are recommended for use as parents in hybridization programmes, as crosses between genetically diverse genotypes are more likely to produce desirable transgressive segregants, thereby facilitating the development of high-yielding, quality okra varieties.

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30. How to cite this article: dangi TS, adivappar N, k R, MV B, HB D. Evaluation and diversity analysis for growth, yield and quality traits in okra [Abelmoschus esculentus (L.) Moench] genotypes. International Journal of Advanced Biochemistry Research. 2026;SP-10(10):28-35. doi: https://www.doi.org/10.33545/26174 693.2026.v10.i10Sa.10252