Format: ORAL

Pooja Singh1 and Krishna Kumar Choudhary1*

1Department of Botany, MMV, Banaras Hindu University, Varanasi-221005, India * presenting Author - email ID - kkc@bhu.ac.in

Ultraviolet (UV-B) radiation is a well-known potent stress factor on this Earths surface caused by stratospheric ozone depletion, which alters morphological, physiological, cytological, and biochemical traits in plants. However, its impact on underutilized plant species such as pearl millet is less explored and further, the question of global food security under climate-changing scenarios can be ascertained. This encouraged the present study to investigate the effects of elevated UV-B (eUV-B) radiation (ambient+7.2 kJm-2d-1) on four cultivars of pearl millet (HHB-272, HHB-67, MPMH-21 and MPMH-17) during May to August 2023 under ambient conditions in the Indo-Gangetic plains of India. Maximum increase in plant height (20%), no. of leaves (31.2%), leaf area (35.4%), and panicle length (60%) was recorded in HHB-272 at grain-filling stage (GFS). Superoxide radicals were initially higher in MPMH-21(47.3%), MPMH-17(28.6%) at panicle development stage (PDS), but later decreased by 35.5%, and 15.3% at GFS. To counter oxidative stress, maximum increase in SOD activity was recorded only at PDS in MPMH-21(35.9%), MPMH-17(34.8%), while declined in all the tested cultivars at GFS. Highest phenolic and flavonoid contents was reported at GFS in MPMH-21(97.2%, 41.7%), and MPMH-17(6.9%,14.9%), respectively. Oxidative damage in terms of malondialdehyde (MDA) content was significantly higher in MPMH-21(46.3%), and MPMH-17(25%), while declined at GFS due to increased phenolic and flavonoid contents, respectively. Yield of tested cultivars was not adversely affected under eUV-B in an ambient tropical condition, but the response varied between them. Grain yield (g m-2) increased significantly in HHB-272(30.2%), HHB-67(55.8%), MPMH-21(83.3%), and MPMH-17(28.6%), respectively. Further investigations are required to assess the impact of elevated UV-B on grain quality characteristics that will be helpful to address the question of food security as well as malnutrition challenges.