桑树多倍体化学诱导剂的筛选及对不同桑树材料的诱变效果

为了高效获取桑树多倍体育种的优良植株,以形态变异率为考核指标,筛选化学诱导剂组合,并对19个桑树品种或杂交组合的不同材料进行诱导处理,改进和丰富桑树多倍体化学诱变技术体系。初步筛选出最佳诱导剂组合0.2%秋水仙素+2%二甲基亚砜(DMSO),用该诱导剂组合分别以滴液法、琼脂涂抹法、注射法诱导处理桑树幼苗顶芽、春伐桑幼芽、桑树雌花,其诱变率分别为30.96%、10.12%、2.56%,而应用该诱导剂组合对桑树种子浸渍诱导9d,可100%获得形态变异植株,其中有11.9%的突变植株成活。以稀释400倍的氟乐灵溶液替代秋水仙素作为诱导剂,采用浸渍法对桑树种子诱导处理5d,其诱变效果与用0.2%秋水仙素+2%DMSO浸渍9d的效果相当。通过植株形态观察和染色体鉴定,确认从12个供试桑树品种或杂交组合中获得了四倍体植株或枝条,可作为桑树多倍体育种的优良亲本材料。

Screening of Chemical Mutagens for Polyploid Mulberry and the Mutagenic Effects on Various Mulberry Materials

In order to obtain the expected mulberry plants from polyploid breeding efficiently,a certain number of different combinations of chemical inductive agents were screened with the index of phenotypic alternation of mulberry treated with different chemical agents and the different mulberry materials were treated with the above inductive agents,of which results will be helpful to improve and enrich the technical system for chemical induction to yield polyploid mulberry.It was found that the best combination of inductive agents was 0.2% colchicine plus 2% DMSO.Treatment with this combination of inductive agents to terminal buds of mulberry seedlings,young buds of mulberry with the branches pruned in spring,and female flowers by means of liquid dropping,agar application,and injection led to a mutation rate of 30.96%,10.12%,and 2.56% respectively.Immersion of mulberry seeds with this combination of inductive agents for 9 d yielded 100% phenotypically altered plantlets,and the average survival rate of mutational plants was 11.9%.When colchicine was replaced by 400 times diluted trifluralin solution which was used to immerse mulberry seeds for 5 d,its mutagenic effect was close to that of 9 d immersion with 0.2% colchicine plus 2% DMSO.Through observation to the mutated plantlets and microscopic examination to chromosomes,it was confirmed that polyploid plantlets or branches have been obtained from 12 mulberry species or branches,which can be further used as parental materials for mulberry polyploid breeding.