Frequencies of Aneuploid Seedlings Obtained from Aneuploid Apple Accessions (Malus x domestica) Pollinated with Diploid 'Hongro'

초록

To estimate the breeding behavior of aneuploid apple (Malus x domestica), twelve crosses were undertaken with twelve aneuploid accessions pollinated with diploid 'Hongro' apple. A 2x x 2x cross with 'Hongro' was also carried out as a control experiment for these aneuploid x diploid crosses. The pollinated aneuploid accessions exhibited relatively high fruit set rates. The apple fruit obtained from the pollinated aneuploid accessions contained less seeds per fruit than those from the 2x x 2x cross. The weight of seeds from the fruits of the pollinated aneuploid accessions was not related to the chromosome number of the aneuploid seed parent. Some of the seeds obtained from the pollinated aneuploid accessions failed to grow into seedlings. Metaphase figures of the root tip cells of seedlings derived from the pollinated aneuploid accessions showed that of 155 seedlings examined 115 were diploid, two were triploid and 38 were aneuploid. The chromosome number of the aneuploid seedlings ranged from 35 to 39, except for 48 chromosomes of one seedling. The seedlings with 35 (2n=2x+1) chromosomes appeared with the highest frequency of 15/38 (39.5%). The chromosome number of the aneuploid seedlings approached to the diploid (2n=34) level, or the number of aneuploid seedlings decreased with increase of chromosome numbers from 35 to 39.

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