Shoot and root growth of micropropagated Marubakaido apple (Malus prunifolia) rootstock inoculated with arbuscular mycorrhizal fungi and subject to root pruning

The effects of mycorrhizal inoculation and root pruning on shoot and root growth by the Marubakaido apple rootstock were evaluated in a growth chamber study. The micropropagated plantlets were dipped in indole-butyric acid and transferred to a soil-based substrate, in order to develop ex-vitro rooting. The plants were inoculated with mycorrhizal fungi before and after a 21-day weaning period, when a root pruning treatment was applied as well. After 51 days, mycorrhizal colonization, shoot length, root and shoot mass and root length and number were assessed. The plants inoculated before weaning had higher root colonization and enhanced shoot mass, in comparison to the plants inoculated after that period. The root pruning significantly reduced the mycorrhizal colonization, shoot mass and root growth. The root number and length were enhanced by mycorrhizal colonization and reduced by pruning. The results indicate that the production of micropropagated Marubakaido rootstocks were benefits from mycorrhizal inoculation and it is damaged by the root pruning.

root architecture; inoculation period; Glomus sp; Scutellospora sp

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