芝麻繁育特性研究Ⅰ:天然异交率的测定

Breeding characteristics of Sesamum indicum L.Ⅰ: Estimations of spontaneous outcrossing rates

根据芝麻良种繁育与种子生产的需要,为明确芝麻天然异交率（SOR）,利用显/隐性单基因控制的相对性状[一组是隐性单基因控制的有限生长习性（D）和闭蒴（C）为标记的性状组合,以正常（N）性状材料为异花粉源;一组是单花（M）/三花（T）性状组合,以显性单基因控制的单花性状材料为异花粉源]为标记,对2010-2012年混合种植和条播2种模式下,5个不同种植区SOR进行了测定。结果显示,混合种植模式下SOR为5.13%～23.35%。不同种植区、不同年份、不同品种间均存在较大差异。SOR与异花粉源的距离有直接关系,随着种植行数的增多,SOR逐渐减少,不同种植区的结果存在一定差异,约在距离异花粉源20～30行（8～12m）未检测到天然异交存在。提出400m空间距离加8～12m保护行的理论隔离方法可以满足芝麻良种繁育（纯度99.9%）的需求,为芝麻良种繁育和种子生产提供了重要理论参考。

For sesame breeding and production,spontaneous outcrossing rates（ SOR） were investigated using2 pairs of morphology markers under 2 planting patterns in 5 areas during 2010 to 2012. In one pair,cultivars with determinated growth habit（ D） and closed capsule（ C） were used. Both traits were controlled by recessive single genes. Corresponding normal（ N） trait materials were used as allogeneic pollen sources. In the other pair,cultivars with monofloral（ M） and trifloral（ T） traits were used. The monofloral was controlled by a dominant single gene and was used as allogeneic pollen source. The 2 patterns were mixed and drilling. Results showed that,under mixed planting patterns,SOR was 5. 13%- 23. 35% with an average of 12. 69%. There were great differences among different planting region,years and cultivars. SOR was directly related to distances among allogeneic pollen sources,SOR gradually decreased with the increase of planting rows. These were differences among planting regions. The SOR were not detected beyond allogeneic pollen sources of about 20- 30 lines（ 8- 12m）. This study suggested an effective isolation distance of 400 m and a buffer zone of 8- 12 m,which was sufficient to meet the demand of sesame seed purity of 99. 9%.