Abstract: The salt tolerance and underlying molecular mechanisms of the hybrid peanut (Arachis hypogaea) cultivar Kainong 80 were systematically investigated. The results revealed that in regional yield trials, the pod yield of Kainong 80 was significantly higher than that of the control variety Yuhua 9327. Under 90 mmol/L NaCl stress during germination, the expression of AhNCED1 in Kainong 80 seeds was markedly down-regulated, while the expression of AhCYP707A1 and AhCYP707A2 was significantly up-regulated, resulting in a reduction in abscisic acid content. Additionally, the expression of AhGA2ox was sharply down-regulated, whereas the expression of AhGA3ox was significantly up-regulated, leading to an increase in gibberellin content. Consequently, the germination vigor, germination rate, and germination index of Kainong 80 under salt stress were significantly higher than those of the control variety Yuhua 9327. Under 200 mmol/L NaCl stress at the seedling stage, compared with the control variety Yuhua 9327,the activity of reactive oxygen species scavenging enzymes in Kainong 80 was significantly increased, and the contents of hydrogen peroxide and superoxide anion were significantly decreased. Therefore, the number of roots of Kainong 80 seedlings was significantly increased, the contents of proline and chlorophyll were significantly increased, while the content of malondialdehyde was significantly decreased, and the survival rate was significantly increased.

Key words: peanut (Arachis hypogaea), Kainong 80, high yield, salt tolerance, gibberellin, abscisic acid, gene expression, reactive oxygen species