【摘要】 本研究以二棱大麦的同源四倍体和二倍体杂交产生的同源三倍体为材料,对其后代染色体的数目及形态变异进行了鉴定和分析。同源三倍体自交结实率很低(2.57—4.35％)。据成活的34株幼苗的染色体鉴定结果,2n+1占52.94％,2n+2占32.33％,2n为11.77％。3n为2.94％。未发现多于16的非整倍体,说明二倍体大麦能容忍额外染色体的限度是很小的。 三倍体和非整倍体植株在减数分裂时,出现落后染色体和具有小核的四分体小孢子,导致结实率降低.叶片气孔大小和花粉粒直径与染色体倍数水平呈正比。 非整倍体植株生长矮小,根据苗期的形态差别可分成若干类型,并穗部出现与原始亲本不同的光芒、曲颈、疏松穗等隐性性状.其中以三体植株(2n+1)出现这些性状最多。这可能与三体具有额外染色体有关。更多还原

【Abstract】 Investigations of chromosome number and some morphological variation in the progenies of autotriploid barley (Horedum vulgare L.) produced by crossing autotetraploid and diploid were carried out.The percentage of fertility of autotriploid was very low (2.57-4.33%). According to the observations made on the root-tips among 34 plants of autotriploid offsprings, their chromosome numbers consisted of 2n+ 1(52.94%), 2n + 2 ( 32.35% ) . 2n ( 11.77% ) .and 3n ( 2.94% ) . There was no plant with chromosome number over 2n+2, indicating that barley as a diploid species had a very narrow tolerance for extra chromosomes.Observations of chromosome behavior of PMC showed that triploid and aneuploid lagging chromosomes and microspores often contained a few micro-nuclei. Therefore, they were the causes of reduced fertility in triploids and aneuploids. The size of stomata and pollen grains was directly proportional to the ploid level.Plants of aneuploids had lower vigour and could be grouped into several types based on the morphological differences at the seedling stage. Some spike variations differing from their parents were observed, such as smooth-awn, neck-curled, loose-spike etc, all being recessive characters. Most of them were trisomics (2n+1). It may be possible that these variations have some relation to the presence of the extra chromosome.更多还原