Strawberries rank among the most economically significant horticultural crops in the United States, with a production value of approximately $3.4 billion in 2023. Year-round demand and widespread popularity necessitate extensive efforts to improve fruit quality, yield, and production in controlled environment agriculture (CEA). As part of these initiatives, optimizing runner production for the year-round availability of planting materials is crucial. The importance of photoperiod and light intensity in runner production has been highlighted previously; however, a thorough exploration of the relationship between the total light quantity received during the entire experimental period and runner production is lacking. This study assessed the responses of strawberry genotypes to sunlight and high-performance LED lighting in runner production. Continuous measurements of photosynthetic photon flux density (PPFD) and daily light integral (DLI) provided an accurate assessment of light exposure during the cultivation period across eight strawberry accessions. In a glasshouse under sunlight, plants experienced variable light conditions due to fluctuating weather, with an average DLI of approximately 10 mol m⁻² d⁻¹, whereas under LED lighting in a growth chamber, a stable DLI of 44.1 mol m⁻² d⁻¹ was recorded. No runner formation was observed under sunlight over 44 days, whereas minimal production in two accessions, PI 551445 and PI 616509, was observed within 12 days following the previous 44-day experimental period, with each accession producing one runner. In contrast, stable and high DLI led to significantly higher runner production. When an ANOVA test was conducted using only runner count data from the stable and high DLI conditions, significant differences in runner formation were observed among the tested strawberry accessions (F value = 2.91, p = 0.03). Accessions PI 616509 and PI 679822 produced the most runners, averaging 6.5 and 4.5, respectively, whereas PI 551692 and PI 551445 produced none and one runner, respectively. These results suggest that strawberry runner production depends on cumulative light exposure and genetic makeup. Overall, these findings provide valuable insights into optimizing strawberry runner production in CEA, demonstrating that stable, high-intensity LED lighting can effectively overcome the limitations of variable natural light and enhance year-round production efficiency.
