High relative humidity increases yield, harvest index, flowering, and gynophore growth of hydroponically grown peanut plants

Growth chamber experiments were conducted to study the physiological and gr owth response of peanut (Arachis hypogaea L.) to 50 % and 85 % relative hum idity (RH). The objective was to determine the effects of RH on pod and see d yield, harvest index, and flowering of peanut grown by the nutrient film technique (NFT), 'Georgia Red' peanut plants (14 days old) were planted int o growth channels (0.15 x 0.15 x 1.2 m), Plants were spaced 25 cm apart wit h 15 cm between channels. A modified half-Hoagland solution with an additio nal 2 mM Ca was used, Solution pH was maintained between 6.4 and 6.7, and e lectrical conductivity (EC) ranged between 1100 and 1200 mu S.cm(-1). Tempe rature regimes of 28/22 degrees C were maintained during the light/dark per iods (12 hours each) with photosynthetic photon flux (PPF) at canopy level of 500 mu mol.m(-2).s(-1). Foliage and pod fresh and dry weights, total see d yield, harvest index (HI), and seed maturity were greater at high than at low RH, Plants grown at 85% RH had greater total and individual leaflet ar ea and stomatal conductance, flowered 3 days earlier and had a greater numb er of flowers reaching anthesis, Gynophores grew more rapidly at 85% than a t 50 % RH.