Influence of UV-B Radiation on In Vitro Seed Germination and Seedling Growth of Cowpea

In vitro seed germination and growth was carried out with three selected varieties viz. GOWMATHI, FOLA and NS-634 of cowpea ( Vigna unguiculata (L.) Walp.) after ultraviolet-B irradiation (UV-B = 2 hours once with 1 hour recovery time @ 12.2 kJ m -2 d -1 ; ambient = 10 kJ m -2 d -1 ). UV-B stressed GOWMATHI seeds under wet condition failed to respond in vitro germination. Control and UV-B stressed FOLA and NS-634 seeds both in dry and wet treatments germinated under in vitro condition. UV-B irradiation suppressed height of seedlings at both dry and wet conditions in all varieties of cowpea compared with control. Root length of UV-B stressed NS-634 equalled control both after dry and wet exposures. UV-B stressed FOLA wet seeds recorded enhancement (50.13%) in plant growth over control. GOWMATHI, FOLA and NS-634 under dry and wet UV-B exposures accumulated less plant biomass (16.66 to 32.50%) compared to controls. FOLA under dry and wet UV-B exposure produced same number of leaves as the control. Seedlings of FOLA and NS-634 varieties of cowpea had the potentiality to survive under ultraviolet-B radiation.