Abstract
Endosperm culture of ‘Tosa-Buntan’ pummelo, which was pollinated by ‘Suisho-Buntan’ pummelo, was performed to breed triploid pummelo. Sampling time of the endosperm and conditions of the culture medium for callus induction, proliferation and regeneration were investigated. Successful culture was obtained when the endosperm was taken 85 to 95 d after pollination and subjected to the culture under the following medium conditions (75% callusing) : basic MS medium (1/2 N) supplemented with 1% sucrose, 1μM BA and 5μM NAA. Sucrose concentrations between 3 to 7% were suitable for calli proliferation. Embryogenesis and rooting were induced from the calli by adding 30μM GA3 to the basic MS medium, though the best medium condition was still unclear. Endosperm callus was estimated to be triploid by the use of ploidy analyzer. Chromosome numbers of the adventitious root tip generated from callus was confirmed as 2n=3x=27 under microscope. Therefore, it was considered that triploid plants would be generated through endosperm culture of ‘Tosa-Buntan’ pummelo.
