Detasseling increases kernel number in maize under shade stress

Abstract Kernel number is one of the critical components of maize yield and is sensitive to environment variation around tasseling when the tassel, stem and ear grow simultaneously. Similar to other areas in the world, the North China Plain faced reduced irradiance during the maize growing season, especially the critical window for determinating actual kernel number. Shade stress that occurs between 15 days pre-silking and 15 days post-silking significantly reduces kernel number and grain yield. In the present experiment, detasseling was conducted under 70% and 97% shade treatments to mitigate the environment stress at the 14-leaf (V14) and tasseling (VT) stages, respectively. Shading treatments significantly reduced kernel number per plant, especially when shading occurred at VT stage. Tassel removal did not relieve kernel losses under 97% shade, but detasseling did dramatically reverse the kernel losses under 70% shade. Removing tassel sink at V14 and VT promoted assimilates being apportioned to ear sink under 70% shade stress, thus encouraging more carbohydrates to be made available for ear growth. Consequently, detassseling increased soluble sugar concentration in the ear section, shortened anthesis-tasseling interval, accelerated ear growth, offering a method to improve kernel number under shade stress.