两种不同亲本材料诱导的桑四倍体产叶量性状的差异

Leaf yield difference between two types of mulberry tetraploid induced from different parent materials:

研究表明，从杂种实生苗诱导的一些桑人工四倍体往往具有高产性状。用下列两种亲本材料及方法诱导四倍体：（１）用２ｍｇ／ｋｇ６ＢＡ配制的０２％秋水仙碱溶液注射到无性系品种的膨芽或生长锥中，每天一次，３～４ｄ；（２）用同样的溶液在杂交实生幼苗子叶展开期滴生长锥，每天一次，持续３～５ｄ。上述两种不同亲本材料和方法诱导的四倍体产叶量有很大的差异：（１）第一组由１２个地方品种无性系诱导的四倍体的平均年产叶量每１０株为１０４９ｋｇ；（２）第二组由１２个杂种幼苗诱导的四倍体的平均年产叶量每１０株为２４９２ｋｇ。两处理差异极显著。而产叶量的显著差异主要由两处理桑树发条性能，即株条长度的极显著差异引起的。

It was found that some mulberry artificial tetraploids induced from hybrid seedlings had higher leaf yielding potential by author's study. Two categories of parent materials and techniques were adopted for induction of tetraploids:(1)about 0.2% colchicine solution prepared with 2 mg/kg 6 BA was injected into the swelling bud or growing cone of clonal variety shoots once a day for 3-4 d,and (2) the same solution was applied to the growing portion of a young seedling at the cotyledon expanding stage once a day for 3-5 d.The tetraploid shoots were perpetuated by grafting.The results showed that the leaf yield of induced tetraploids from two group was very different. The average annual leaf output of 2 years old trees was:(1) 10 49 kg/10 plants in first group of the tetraploids induced from 12 clonal varieties (mainly leading and local var.in the province);and (2) 24 94 kg/10 plants in 2nd group of the tetraploid induced from young hybrid seedlings.The leaf yield existed a great significant difference between them.The main reason of which was the great difference of branch length per plant between two groups.It is suggested that the reason of high yielding in 2nd group may be the heterosis existence in the parent materials of hybrid seedling.