Investigation on chromosome ploidy of the hybrids of Phalaenopsis polyploids.

The microspore mother cell meiosis of different ploidy Phalaenopsis and chromosome number in root tip cell of their hybrids were observed.The results showed that the ploidy segregation appeared in all combinations except that of triploid×triploid,in which no hybrid plants were obtained.Diploid,triploid and tetraploid plants were identified in the combinations of diploid×diploid,diploid×tetraploid and tetraploid×diploid Phalaenopsis.Diploids,triploids,pentaploids and aneuploids were found in the combinations of diploid×triploid and triploid×diploid.Triploids,tetraploids,octoploids and aneuploids were identified in the plants of triploid ×tetraploid combinations,while triploids,tetraploids,pentaploids and aneuploids existed in the plants of tetraploid triploid ones.This indicated that ploidy segregation was related to reciprocal crosses.Tetraploid crossed with tetraploid produced diploids,triploids,tetraploids,pentaploids,hexaploids and aneuploids.The ploidy diversity of microspore in Phalaenopsis caused by the abnormal meiosis of microspore mother cells such as chromosome lagging,micronucleus and triad,was one of the main reasons resulting in ploidy diversity of the hybrids.