Interactive Effect of Growth Medium, Moist Chill Stratification and Gibberellic Acid Scarification on Kiwi (Actinidia deliocia) Seed Germination

Abstract

Kiwifruit is an economically important temperate fruit crop propagated commercially through grafting. Seed germination is essential for the production of vigorous rootstocks; however, physiological dormancy often limits germination performance. The present study evaluated the interactive effect of growth medium, moist chill stratification, and gibberellic acid (GA₃) application on kiwifruit seed germination under greenhouse conditions at Wengkhar Agriculture Research and Development Centre, Bhutan. A 4 ×2×2 factorial experiments arranged in a Completely Randomized Design with three replications was used. Four growth media (cocopeat, biochar, rice bran, and compost), two stratification durations (24 hours/0-week and eight weeks), and two GA₃ concentrations (0 and 1500 ppm) were evaluated.

Among the growth media, cocopeat treated with 1500 ppm GA₃ recorded the highest germination percentage (52.83%), whereas rice bran exhibited the lowest germination performance. The mean germination time averaged 50 days, the coefficient of variation of germination time averaged 71.88%, and the mean germination rate averaged 0.01 day-¹, with neither parameter significantly affected by growth medium, stratification, or gibberellic acid treatment. Moist chill stratification showed no significant effect on germination percentage, suggesting that maintaining seed moisture before sowing effectively reduced dormancy. The interaction between growth medium and GA₃ significantly improved germination performance. The study demonstrates that cocopeat combined with 1500 ppm GA₃ is suitable for enhancing kiwifruit seed germination and rootstock production.

SAARC J. Agric., 24(1): 43-49 (2026)