IN-VITRO SELECTION OF SALT-RESISTANT VIGNA-RADIATA (L) WILCZEK PLANTSBY ADVENTITIOUS SHOOT FORMATION FROM CULTURED COTYLEDON EXPLANTS

Salt-resistant plants of Vigna radiata (L.) Wilczek were selected by s creening cotyledon explants in vitro on high concentrations of NaCl. N aCl delayed shoot organogenesis by 7 - 10 days and also decreased the number of explants forming shoots and number of shoots per explant. Co ncentrations higher than 150 mol m-3 proved inhibitory to shoot format ion. Out of 850 explants cultured on medium containing 200 mol m-3 NaC l, three survived and each regenerated one shoot. The shoots selected on salt showed persistence of salt tolerance not only during their in vitro multiplication in the absence of NaCl with up to 3 passages of 1 month each, but even their calli maintained on normal medium for 2 mo nths retained salt tolerance. The selected shoots were rooted on MS me dium supplemented with IAA (5 X 10(-6) M) and NaCl. The plantlets were transferred to soil and grown to maturity. The regenerants flowered p recociously, but produced normal pods and viable seeds.