Varietal influence on vase life and post-harvest attributes of cut gerbera flowers: Identifying morphological markers for extended marketability

Introduction

Gerbera (Gerbera jamesonii Bolus ex. Hooker f.), a member of the Asteraceae family native to South Africa and Asia, ranks among the top ten most commercially significant cut flowers globally (Singh, 2006) [12] . Valued for its vibrant colors, diverse forms, and considerable vase life, gerbera has undergone extensive breeding, resulting in numerous cultivars with varied morphological and physiological characteristics (Kaur et al., 2021) [6] . In recent decades, the Pomponi Mini types have gained popularity for their compact growth habit and charming, double-petaled, pom-pom like blooms, particularly suited for bouquet arrangements and decorative purposes. The global floriculture industry faces increasing competition, with post-harvest longevity emerging as a critical quality parameter that directly influences consumer preference, market price, and profitability (Jafarpour et al., 2015) [4] . Extended vase life reduces transportation losses, expands market reach, and enhances customer satisfaction, making it a primary breeding objective for gerbera improvement programs. Protected cultivation under polyhouse conditions has become standard practice for commercial gerbera production, allowing for climate control, year-round production, and protection from environmental stressors (Ponnuswami & Sowmeya, 2015) [9] . However, even under optimal growing conditions, considerable variation exists among varieties in their post-harvest performance, largely attributable to genetic differences in water relations, carbohydrate metabolism, ethylene sensitivity, and structural integrity (Kandpal et al., 2003; Silva et al., 2015) [5, 10] . Post-harvest senescence of cut flowers involves complex physiological processes including water stress due to xylem blockage, carbohydrate depletion, membrane deterioration, and hormonal changes, particularly ethylene biosynthesis and sensitivity in some species (Jafarpour et al., 2015) [4] . In gerbera, vascular occlusion in the stem has been identified as a primary cause of vase life termination, suggesting that stem anatomical features may significantly influence water uptake and longevity (Malakar et al., 2019) [7] . Previous studies have documented varietal differences in gerbera vase life (Singh & Srivastava, 2008; Wankhede & Gajbhiye, 2012) [11,13] , but limited research has systematically examined the morphological correlates of post-harvest longevity, particularly in Pomponi Mini types. In the Indian context, where gerbera cultivation has expanded significantly in states like Telangana, identifying varieties with superior post-harvest attributes is essential for enhancing competitiveness in both domestic and export markets (APEDA, 2022) [2] . The selection of appropriate varieties based on scientific evaluation can substantially improve profitability and sustainability of gerbera cultivation enterprises. This study was therefore conducted with the objectives of: (1) evaluating ten Pomponi Mini gerbera varieties for key post-harvest quality parameters under polyhouse conditions, (2) identifying morphological traits correlated with extended vase life, and (3) recommending superior varieties for commercial cultivation based on comprehensive postharvest assessment.

Materials and Methods

Experimental Site and Conditions

The investigation was conducted from December 2024 to May 2025 at the Floricultural Research Station, Rajendranagar, Hyderabad, Telangana, India (latitude 17.32°N, longitude 78.40°E). The experiment was established in a naturally ventilated polyhouse (NVPH) oriented north-south and covered with 200-micron UVstabilized polythene film. The region experiences a semiarid climate, with meteorological data during the experimental period presented in Table 1.

Cultural Practices

Drip irrigation with two laterals per bed and drippers spaced at 30 cm intervals maintained optimal soil moisture. Fertigation employed water-soluble fertilizers: N:P:K (19:19:19) at 100 g + Micromax at 10 g per liter water for the first three months to promote vegetative growth, followed by N:P:K (12:16:0) at 100 g + N:P:K (13:0:45) at 125 g per liter water at weekly intervals during the flowering phase. Regular hand weeding and removal of senescent leaves were performed at 15-day intervals. Disbudding of early and inferior quality flowers was practiced to enhance floral quality. Integrated pest management involved prophylactic sprays of dimethoate (30EC@2 ml/L), imidacloprid ([email protected] ml/L), spinosad (@ 0.3 ml/L), abamectin (@ 1.4 ml/L), and acephate (@ 1.5 g/L) at regular intervals, supplemented with blue and yellow sticky traps for sucking pests. Fungal diseases were managed through carbendazim drenching (2 g/L) near the root zone weekly.

Data Collection

For post-harvest evaluation, flowers were harvested in early morning hours when the outer row of ray florets were fully elongated and two rows of disc florets were fully developed.

Harvesting involved gently pushing the flower stem sideways at its base, after which flowers were immediately placed in fresh water.

Recorded as the number of days from complete flower opening to the onset of wilting, with mean values calculated from five tagged plants per treatment.

Determined using a digital balance (precision 0.01 g) immediately after harvest, with the average of five flowers per treatment.

Evaluated by placing individually harvested flowers in conical flasks containing 200 ml distilled water maintained at ambient laboratory conditions (25±2 °C, 65±5% RH). The basal 1-2 cm of each stem was re-cut daily at a 45° angle under water. Vase life termination was defined as the onset of petal wilting, bending of the peduncle by more than 45°, or visible dehydration of floral parts. Observations were recorded daily until termination.

Associated morphological parameters:

Flower stalk diameter (measured at midpoint using digital vernier calipers, mm), flower stalk length (from point of origin to just below flower head, cm), and flower diameter at complete opening (cm) were recorded from the same flowers used for post-harvest evaluation.

Statistical Analysis

Data were subjected to analysis of variance (ANOVA) following the procedure for RBD as outlined by Panse and Sukhatme (1954) [8] . Treatment means were separated using Duncan's Multiple Range Test (DMRT) at p = 0.05. Pearson's correlation coefficients were calculated to determine relationships between vase life and various morphological parameters. Linear regression analysis was performed to quantify the predictive relationship between stalk diameter and vase life. All statistical analyses were conducted using SPSS Statistics version 25.0.

Results

Varietal Performance for Post-Harvest Parameters

Highly significant differences (p<0.01) were observed among the ten gerbera varieties for all post-harvest quality parameters evaluated (Table 2). The analysis of variance revealed substantial genotypic variation, with the treatment (varietal) effect being highly significant for all measured traits. Longevity of flowers on the plant ranged from 6.33 to 9.93 days, representing a 56.9% difference between the lowest and highest performing varieties. 'Fozzie' demonstrated the maximum longevity of 9.93 days, which was statistically comparable to 'Janice' (9.27 days) and 'Tracy' (8.87 days). 'Camilla' exhibited the shortest longevity at 6.33 days, significantly lower than all other varieties except 'Black Pearl' (6.80 days) and 'Floyd' (6.93 days). Fresh weight at harvest showed even greater varietal disparity, ranging from 11.34 g to 20.65 g (82.1% variation). 'Black Pearl' produced the heaviest flowers (20.65 g), significantly surpassing all other varieties. This was followed by 'Fozzie' (19.30 g), while 'Beaker' recorded the lowest fresh weight (11.34 g). Notably, varieties with higher fresh weight did not necessarily exhibit extended vase life. Vase life in distilled water varied from 5.11 to 8.56 days, with 'Fozzie' again demonstrating superiority (8.56 days), statistically comparable to 'Gonzo' (7.78 days) and 'Black Pearl' (7.33 days). The shortest vase lives were recorded for 'Bunny' (5.11 days), 'Honeydew' (5.22 days), and 'Floyd' (5.89 days). This parameter showed the most commercially significant variation, with 'Fozzie' exhibiting 67.5% longer vase life than 'Bunny'.

Morphological Characteristics of Varieties

Significant varietal differences were observed for all morphological parameters measured (Table 3). 'Fozzie' exhibited the thickest flower stalks (6.01 mm), which was statistically superior to all other varieties. 'Bunny' produced the longest stalks (51.95 cm), while 'Fozzie' again had the largest flower diameter (8.17 cm).

Correlation Analysis Between Vase Life and Morphological Parameters

Correlation analysis revealed distinct relationships between vase life and various morphological flower characteristics (Table 4). Flower stalk diameter showed a very strong positive correlation with vase life (r = 0.84, p<0.01), indicating that varieties with thicker stalks generally exhibited longer post-harvest longevity. Conversely, flower stalk length displayed a moderate negative correlation (r = -0.44), though this relationship was not statistically significant (p = 0.20). Fresh weight demonstrated a weak positive correlation (r = 0.32, p = 0.36), while flower diameter showed essentially no relationship with vase life (r = 0.07, p = 0.85). Longevity on the plant was weakly correlated with vase life (r = 0.25, p = 0.48).

Regression Analysis: Stalk Diameter as a Predictor of Vase Life

Given the strong correlation between stalk diameter and vase life, linear regression analysis was performed to quantify this relationship (Table 5, Figure 1). The regression equation was determined as: Vase Life (days) = 1.92 × Stalk Diameter (mm)-2.47 (R² = 0.706, p<0.01). This model explains 70.6% of the variation in vase life based on stalk diameter alone, confirming its utility as a predictive morphological marker. The regression slope of 1.92 indicates that for each 1 mm increase in stalk diameter, vase life increases by approximately 1.92 days under the experimental conditions. The 56.9% difference in longevity on plant and 67.5% difference in vase life between the poorest and best performing varieties have significant commercial implications. These findings align with previous reports of considerable varietal variation in gerbera post-harvest performance. Wankhede and Gajbhiye (2012) [11,13] documented vase life ranging from 9.96 to 15.16 days among thirteen gerbera varieties under shade net conditions, while Deka and Talukdar (2015) [3] reported variations from 4.10 to 9.81 days in twelve cultivars grown in open fields in Assam. The relatively shorter vase lives observed in the present study (5.11-8.56 days) compared to some earlier reports may be attributed to the evaluation in distilled water without preservatives, which represents a more stringent test of intrinsic varietal characteristics rather than maintained potential with floral preservatives (Jafarpour et al., 2015) [4] . The exceptional performance of 'Fozzie' across multiple post-harvest metrics-top-ranking in both vase life (8.56 days) and longevity on plant (9.93 days), while maintaining high fresh weight (19.30 g, second only to 'Black Pearl')identifies it as a superior genotype for commercial cultivation. This comprehensive superiority suggests that 'Fozzie' possesses a combination of favorable traits including efficient water relations, robust vascular anatomy, and possibly lower sensitivity to senescence-inducing factors. The consistency between longevity on plant and in vase suggests that similar physiological mechanisms govern flower senescence in both conditions, though additional factors like stem-end blockage become more prominent in cut flowers (Silva et al., 2015) [10] .

The Critical Role of Stalk Diameter in Vase Life Determination

The strong positive correlation between flower stalk diameter and vase life (r = 0.84, p<0.01) represents the most significant finding of this study. This relationship explains 70.6% of the variation in vase life according to regression analysis, establishing stalk diameter as a reliable predictor of post-harvest longevity. From a physiological perspective, thicker stalks likely contain larger vascular bundles with greater xylem vessel diameter and number, enhancing water conductance capacity and reducing hydraulic resistance (Malakar et al., 2019) [7] . This is particularly relevant for gerbera, where stem blockage due to microbial growth, physiological plugging, and cavitation has been identified as a primary cause of vase life termination. Additionally, thicker stalks typically contain greater carbohydrate reserves in parenchyma tissues, which can be mobilized to support post-harvest metabolic demands, thereby delaying senescence (Jafarpour et al., 2015) [4] . The structural robustness of thicker stalks may also better resist bending or buckling, maintaining vascular continuity and water uptake. These findings have practical implications for breeding programs, suggesting that selection for increased stalk diameter could indirectly enhance vase life. This is particularly valuable as stalk diameter is easily measurable in early selection cycles, unlike vase life which requires destructive testing at flowering. The negative correlation between stalk length and vase life (r = -0.44), though not statistically significant in this study with ten varieties, aligns with the hydraulic limitation hypothesis which proposes that longer stems experience greater hydraulic resistance and are more susceptible to embolism (Kandpal et al., 2003) [4] . This relationship merits further investigation with larger sample sizes, as it suggests potential trade-offs between stem length (an important aesthetic and handling characteristic) and longevity.

Fresh Weight and Flower Diameter: Limited Predictive Value

The weak correlation between fresh weight and vase life (r = 0.32, p = 0.36) indicates that simply selecting for heavier flowers does not guarantee extended post-harvest life. While 'Black Pearl' produced the heaviest flowers (20.65 g), its vase life (7.33 days) was substantially shorter than that of 'Fozzie' (8.56 days) despite lower fresh weight (19.30 g). This suggests that factors other than biomass accumulation, such as tissue composition, water content proportion, and structural integrity, play more direct roles in determining longevity. Similarly, the negligible correlation between flower diameter and vase life (r = 0.07, p = 0.85) indicates that aesthetic preference for larger blooms can be pursued independently without compromising post-harvest performance, an important consideration for breeding programs targeting multiple quality traits.

Physiological Implications and Practical Applications

The differential post-harvest performance among varieties likely stems from variations in several physiological processes. Varieties with extended vase life may possess: (1) more effective antioxidant systems delaying oxidative membrane damage, (2) lower ethylene production or

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