茶树品种‘白鸡冠’叶色性状遗传特性研究

Genetics on Color of Baijiguan Tea Leaves

近年来黄白化茶树品种推广面积快速增长,但其叶色性状的调控机制仍未清楚。本研究以‘白鸡冠’为材料,研究其叶色性状的遗传特性。试验发现‘白鸡冠’叶色性状与‘白叶1号’(安吉白茶)、安吉黄茶(地方种质)的遗传特性不同,白鸡冠叶色受显性单基因控制,且叶色性状能在世代间稳定遗传。白鸡冠叶色黄化程度受温度影响,生长环境温度越低叶色越黄,说明调控黄化性状的基因位点属于温度敏感基因,结合已有研究推断白鸡冠叶色性状可能同时受温度和光照调控。白鸡冠黄化叶片随着叶龄的增加逐渐返绿,说明叶绿素合成途径没有遭受破坏,而是合成速率受到抑制或是叶绿体结构的形成出现障碍。白鸡冠黄化新梢整体抗逆性比一般品种差,尤其容易受冻害。

Cultivation of yellowing albino tea has expanded rapidly in recent years.However,the genetic mechanism regulating the leaf color of the plant remains largely unknown.As a typical cultivar showing such genetic trait,Baijiguan(Camellia sinensis)was selected to study the etiolation and albinism on tea plants.It was found that the genetics of Baijiguan were indeed different from that of Baiye 1(Camellia sinensis)or Anji huangcha(Camellia sinensis).The color of Baijiguan leaves was controlled by a single dominant gene which could be steadily passed on from generation to generation.The yellowing of leaves was affected by temperature.As the surrounding environment cooled down,the leaves turned yellow.As reported by other studies,the gene locus was regulated by light as well.The green color on leaves would gradually return as the plant aged,suggesting that the chlorophyll synthesis pathway in the leaves was intact after the exposure,only the synthesis rate was inhibited and/or the chloroplast formation impeded temporarily.The overall stress resistance of the new yellow shoots on a Baijiguan plant was weaker than that of common tea cultivars.The shoots were especially susceptible to freeze injury.