人工无性系四倍体桑品种陕桑402的选育

Breeding of a Mulberry Clone Tetraploid Variety,Shansang 402

采用0．1％-0．4％的秋水仙碱处理二倍体桑品种新一之濑（2n=2x=28）当年嫁接苗的茎尖，诱导出8个突变株，将这些突变株按株系进行单芽分离嫁接，发现编号为402—3的株系在所分离出的四倍体（2n=4x=56）株系中性状突出，经系统选育培育成无性系四倍体品种陕桑402（2n=4x=56）。该品种发芽率高，生长旺盛，在北方蚕业科研协作区域试验的桑叶产量较湖桑32号（2n=2x=28）提高26．9％，万头茧层量增加5．4％，抗逆性强，是一个综舍性状优起、丰产性能突出的人工无性系四倍体桑品种。

Eight mutant plants were induced by treating the stem-point of diploid cultivar sinichinose（2n =2x = 28）with 0. 1%-0.4% colchicines. A tetraploid plant 402-3 had been obtained by clonal separation in mutant plants. And a mulberry artificial clone tetraploid variety,Shansang 402 （2n =4x =56）, had been bred by pedigree breeding method. Shansang 402（2n =4x =56） presents a higher occurrence rate and a vigorous growth. The regional test results showed that comparing with the control, Husang 32, the leaf yield increased by 26.9% and the cocoon shell amount per 10 000 silkworms increased by 5.4%. The above results showed that Shansang 402 is a fine variety with outstanding high-yielding ability and adverse resistance.