染色體轉座對玉米結實率影響之研究

Abstract

當玉米之染色體轉座呈異型接合時，由於產生之部分配子其染色體發生重複與缺失，而導致稔實率下降。為求探討染色體轉座對稔實率之影響，本試驗利用⊙4 與⊙6 轉座異型接合組合為材料，調查其稔實率，得知⊙4 組合為50%，⊙6 組合為弱％。此乃由於參與轉座異型接合之染色體在進行減數分裂時，發生同對取向方式之分離，因而產生部分無效配子導致稔實率下降。至於稔實率下降之程度則與參與轉座之染色體數目有關，稔實率＝2 / 2n × 100%，其中n為發生轉座異型接合之染色體對數。 The fertility of translocation heterozygote would decrease because of some gametes were aborted at gametogenesis due to chromosome segments duplication and deletion. To investigate the effect of chromosomal translocation on fertillity, we examed the fertilities of translocation homozygotes and heterozygotes of ⊙4 and ⊙6 combinations. The results showed that: Fertilities of ⊙4 combinations were about 50% and ⊙6 were about 25%. Because of translocated chromosomes were separated by co-orient segregation in meiosis of translocation heterozygotes so that some gametes would be aborted and fertility decreased. The decreament of fertilities were positively correlated with the number of translocated chromosomes involved in translocation heterozygotes, that fertility should be calculated by 2/2n×100%, n: denote the number of pairs of translocated chromosomes.