Cytoplasmic effects on the regeneration ability of sunflower

Highly varible organogenic regeneration has been obtained in sunflower, depending upon culture conditions, genotype and their interactions and now the effect of cytoplasm upon regeneration ability has been analysed. Six sunflower inbred lines in their male-sterile and malefertile forms were evaluated in vitro : HA89, GP762, HA300, RK416, RK456, and KLM280. The basal medium was agar solidified Murashige and Skoog (MS) medium supplemented with plant hormones: KIN 2mg/1 + IAA 1 mg/1 (Ml); BA 0.5mg/1 4- IAA 0.5mg/1 (M2). Cotyledons of mature seeds were used as explants. Regeneration ability (R) was evaluated on day 30 after initiation of culture. Significant differences were observed between male-sterile and male-fertile forms of some inbred lines for R on M2 medium. The presence of interaction among the factors line-cytoplasm-regeneration on M2 was demonstrated by using a G-test. This nucleus-cytoplasm interaction affects the regeneration ability of this species and should be taken into account when using tissue culture for crop improvement.