Influence of LED light spectrum and photoperiod on flowering, fruit set and morphological traits of cherry tomato (Solanum Lycopersicum var Cerasiforme) lines under indoor controlled conditions

Introduction

Cherry tomatoes (Solanum lycopersicum var. cerasiforme) are developing milestone of modern agriculture which belongs to Solanaceae family. In worldwide, cherry tomatoes (Solanum lycopersicum var. cerasiforme) are gaining significant popularity due to their small size, short life cycle and vivid appearance. Netherlands, Spain, Italy and Canada are major producing countries grown under high tech greenhouse and indoor infrastructure conditions. Cherry tomatoes are rich in vitamins, minerals, fibers and also having high concentration of antioxidants like carotenoids, flavonoids and phenolic compounds. Cherry tomatoes which having health benefits such as heart disease protection, cancer prevention and skin damage reduction from the UV light (Baek et al., 2024; Dong et al., 2024) [1,2] . Nowadays, crops are growing under indoor controlled environment like green house and vertical farming units to protect the plants from external sources like abiotic and biotic factors and also year-round food production for the global demand. Vertical farming grows crops in vertically stacked layers within controlled indoor environments, using significantly less land and water than conventional agriculture (Van et al., 2021) [3] . Meanwhile, modern LED developments have transformed indoor farming by enabling exact customization of light quality, photoperiod and spectrum. Unlike traditional lighting sources, LEDs emit customizable light spectra that can be optimized to match specific plant photoreceptors. In particular, red and blue wavelengths play the most critical roles in plant physiology: red light drives photosynthetic activity and supports reproductive development while blue light is essential for chloroplast development, stomatal opening and compact morphological growth (Izzo et al., 2020) [4] . Despite widespread recognition of the importance of spectral quality, significant research gaps remain regarding how light spectrum interacts with photoperiod (day length) across different genetic lines of cherry tomatoes. Most existing studies focus on general vegetative responses leaving a lack of detailed understanding on how specific combinations of light spectrum and photoperiod alter the balance between morphological development and reproductive performance such as flowering, fruit set and yield metrics in distinct cherry tomato lines. To address these knowledge gaps, the present study evaluates the interactive effects of various light spectra and photoperiodic regimes on the morphological traits and reproductive outcomes of selected cherry tomato lines under controlled indoor conditions. By clarifying these physiological responses, this research aims to establish optimized lighting protocols modified to specific genotypes in commercial vertical farming systems.

Materials and Methods

An indoor vertical experiment was conducted during 2025-2026 at the Urban Kissan private limited, Gundlapochampally, Hyderabad. The experimental location was situated at latitude 17°34′ N and longitude 78°28′ E with an elevation of 15.0 m above the mean sea level. The experimental facility comprised a vertical growing system equipped with LED lighting units and maintained under controlled environmental conditions. Cherry tomato lines (UK1 and UK2) used as the planting material. The seeds used in the experiment were obtained from Urban Kisaan Research and development.

Experimental design

To evaluate the flowering and reproductive responses of indoor-cultivated cherry tomatoes under varied illumination regimes, a Factorial Completely Randomized Design (FCRD) was employed. The study evaluated two primary factors: cultivar line and lighting conditions. Two distinct cherry tomato genotypes (UK1 and UK2) were subjected to five light regimes (P 1 to P 5 ), which incorporated different red-toblue spectral ratios (2R:1B and 1R:2B) across two photoperiod durations (14-h and 16-h daylengths). The factorial combination of these two factors yielded ten distinct treatment groups (T 1 -T 10 ). Each treatment combination was replicated in three times within a controlled vertical farming environment to systematically assess its impact on floral transition and reproductive performance. The number of flowers per cluster varied significant between the lines of cherry tomato and applied across the different light spectrum-photoperiod combinations (Table 2). Overall, UK 2 line (7.00) which produces more flower count per cluster compared to UK 1 line (6.37). Among the light regimes, 2Red:1Blue spectrum combined with 16 hours photoperiod (P 4 ) recorded maximum number of flowers (8.47) whereas 1Red:2Blue with 14 hours and control having lowest mean values of flower production. Best treatment combination recorded in UK2 and 2R:1B with 16 hours (T 9 ) which achieved highest flower density (8.73) compared to all other treatments. These results demonstrate that red-dominated light spectrum paired with an extended photoperiod enhances floral production in cherry tomatoes. Similar findings which align with the current study was supported by Zhang et al (2025) [5] who reported increase in flowers count per cluster observed in tomatoes subjected to balanced red-blue light regimes with longer photoperiods. Fruit set per cluster which show significant variation influenced by genetic and lighting conditions. UK2 line consistently produced more fruits (6.41) than the UK1 line (6.17). The red-enriched spectrum (2Red:1Blue) under a 16-hour daylength promoted greater fruit set (7.48), whereas blue dominated spectrum (1Red:2Blue) with 14 hours photoperiod and control recorded the less fruit production. Across all treatment combinations, superior performance in fruit set was recorded under UK2 and 2R:1B with 16 hours (T 9 ) as 7.73. The current findings are consistent with previous observations of palmitessa et al (2020) [6] who recorded the more fruit set per truss in Juanita tomato cultivar exposed to supplemental light treatments. Fruit production per plant which show clear response towards the quality and duration of artificial light regimes. From the evaluated data, UK2 line (36.20) produces more number of fruits than UK1 line (33.73). Among the light treatments, 2Red:1Blue with 16-hour photoperiod recorded maximum number of fruits per plant (52.77) compared to the control treatment. The interaction between light quality and photoperiod markedly influenced reproductive development which leads to maximum fruit count as 55.65 under UK2 and 2R:1B with 16 hours (T 9 ). The increased fruit number under extended photoperiod was comparable with findings of Gomez et al (2016) [7] who observed enhanced highest fruit production in tomato crop grown under more dominant red-light spectra and 16-hour day length. The results obtained in the present study are comparable with those of Watjanatepin (2019) [8] who observed increased fruit elongation under extended exposure of red enriched light spectrum. [9] experimented on the cherry tomato plant recorded highest fruit diameter under 65Red:25Blue spectrum over 16-hour photoperiod.

Results and Discussion

Number of flowers per cluster

Number of fruits per cluster

Number of fruits per plant

Conclusion

The results obtained under experimental conditions clearly demonstrated that the interaction between LED light spectrum and photoperiod significantly influenced that flowering and reproductive performance of cherry tomato lines present in an indoor vertical controlled system. The two cherry tomato lines exhibited variation in their growth and reproductive characteristics, indicating the importance of genotype-specific responses to controlled light environments. Among the treatment combination, UK2 and 2R:1B spectrum combined with a 16-hour photoperiod (T 9 ) generally promoted best performance in the flowering, fruit setting and also fruit characteristics particularly in terms of number of flowers per cluster, number of fruits per cluster, number of fruits per plant, fruit length and fruit diameter. These outcomes illustrate that red-dominant light regimes combined with extended daylengths facilitate efficient floral development and yield formation. Overall, the findings indicate that optimizing LED spectral composition and photoperiod can be an effective approach for improving cherry tomato production in indoor vertical farming systems. The combination of 2R:1B LED spectrum with a 16-hour photoperiod showed promising performance under the conditions of the present study.

References

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10. How to cite this article: Bhargavi MS, Bharathi P, Jayasree V, Chakraborty M, Mahesh G. Influence of LED light spectrum and photoperiod on flowering, fruit set and morphological traits of cherry tomato (Solanum Lycopersicum var Cerasiforme) lines under indoor controlled conditions. International Journal of Advanced Biochemistry Research. 2026;SP-10(10):895-899. doi: https://www.doi.org/10.33545/26174693.2026.v10.i10Sk.10395