Response of Peanut ( Arachis hypogaea ) to Increasing Levels of Blue Light

Growth chamber experiments were conducted to determine the effect of varying levels of blue photons on branch growth, pod and seed yield of peanut. Seeds of ‘Georgia Red’ peanut cultivar were grown in 10-liter plastic pots containing a vermiculite/sand/soil media (1:1:1 v/v) under 6%, 11%, 16%, 21% and 26% blue light (320–496 nm) supplied by high intensity discharge high pressure sodium (HPS) and metal halide (MH) lamps at equal photosynthetic photon flux (PPF; 1100 μmol m⁻²s⁻¹). Neither total foliage nor pod fresh and dry mass were significantly affected by increasing blue light fraction. The length of main stem (plant height) declined linearly in response to increasing blue light fraction. Likewise, both the number and dry mass of mature pods decreased linearly as the percentage of blue light increased. The number of mature seeds declined linearly with increased blue light, while the decrease in seed dry mass was not significant. The dry mass of immature seeds was increased with blue light fraction up to 16%, but decline thereafter. Harvest index declined linearly as blue light fraction increased.