小麦抗穗发芽研究方法的初步评价

Evaluation on Study Methods of Sprouting Tolerance in Wheat

对 10 6份小麦不同灌浆时期的穗发芽和种子发芽进行了测定 ,7份具不同穗发芽抗性基因型的完整穗、脱粒种子和切取的胚部发芽测试以及抗穗发芽小麦与易穗发芽小麦杂交的F2 单株测定与遗传分析。结果表明 :①由于不同基因型的灌浆速度、生理成熟和种子脱水速度不同 ,导致不同基因型的发芽高峰值出现在不同时期 ;②不同基因型的胚发芽率随灌浆期延长而增加 ,种子发芽和穗发芽率则呈现各自的高峰值 ,说明不同基因型的穗发芽抗性来源于胚以外的其他方面的抑制 ,因而在作遗传分析时 ,F1植株上的种子 (胚 )发芽应视为F1的表现 ,其他类推 ;③由于穗发芽受环境影响很大 ,通过简单的“抗×易”杂交和F2 的单株测试 ,有时不能准确地判定控制基因的数目 ,而单体和双端体分析能够较好反映基因所在的染色体或染色体个数和表达的显隐性关系等 ;④由于很难一次性地确定F2 所有单株的真实差异 ,因而在进行分子标记时 ,经过多年测定的稳定株系为对象较为可靠 ;⑤对穗发芽测试所涉及的问题作了简要讨论。

Germination of intact spikes and seeds of 106 genotypes at 3 stages,germinations of intact spikes, threshed seeds and embryos of 7 genotypes with different tolerance at 6 stages were measured. It indicates that the maximum of germination rate occurs at varying stages for the 106 entries due to the difference of grain filling rate, physiological maturity and seed dehydrate. Germination of seeds and spikes reach their peak values at different stages along with grain filling, although the embryo's germination of all genotypes increases continuously. The sprouting tolerance of various genotypes is derived from the inhibition outside embryos. So, in genetic analysis on germination, the seeds produced by F 1 plants should be judged as F 1, not F 2. The sprouting is largely influenced by environments, to determine gene's numbers in F 2. The analysis by monosomic or ditelosomic plants could clarify the genetic base of genes controlling sprouting. It is difficult that the real difference in F 2 plants are determined once, so it is better that the stable lines tested for years are used in molecular marker. This paper also discusses about problems on testing methods of preharvest sprouting at last.