Higher Light Intensity Combined with Optimized Photoperiod Enhances Growth and Tassel Development in Maize Inbred...

Maize has a long generation cycle and sensitivity to photoperiod, which limit breeding efficiency. An LED plant factory with suitable light conditions provides a promising approach to overcoming challenges in speed breeding. This study optimized the LED light environment to enhance growth and tassel development in the maize inbred line from the V3 to V9 stages. Six lighting treatments were tested, combining three light intensities (800, 1200, and 1600 μmol m^-2 s^-1) and two photoperiods (10 h d^-1 and 12 h d^-1). Treatment with a light intensity of 1600 μmol m^-2 s^-1 and a photoperiod of 10 h d^-1 resulted in the highest shoot fresh weight (396.9 g per plant), shoot dry weight (42.4 g per plant), leaf area (51.3 dm² per plant), and stomatal length (34.6 μm), as well as improved photosystem performance. Furthermore, this treatment promoted tassel development, with the tassel length at the V9 stage being 45.8% longer than that under the treatment with a light intensity of 800 μmol m^-2 s^-1 and a photoperiod of 10 h d^-1. These findings establish an optimized lighting strategy that significantly enhances the growth and tassel development of maize inbred lines from the V3 to V9 stages, providing a suitable light environment for maize speed breeding in plant factory systems.