Study On Improved Strains Breeding Of Undaria Pinnatifida

In order to obtain high yield strains of Undaria pinnatifida,the populations of DL8,DL13,DL18 and DLYS1 were selected and crossedafter selection breeding from30 Japanese original populations(DL 1-19,LS 1-11)and 10 Dalian local populations(DLYS 1-5,LSYS 1-5),meanwhile,the gametophytesof DL18 populations weretreated with high voltage electrostatic field to investigate their growth and development by indoor culture,seedling raising,sea temporary breeding and cultivation,of which F1 generation the rbcL,rbcL-rbc S spacer,partial of rbc S sequences(rbcL-sp-S)being analysed.Selective breeding experiments' results show that: The 40 populationswere roughly divided into the following 7 types:(1)Large body type: body length >2.8m,weight >1.5kg,such as the strains of DL8?DL18?DL13;(2)Short stemtype: stem length<10 cm,such as the strains of DL1?DL4?DL5?DL12?DL15?DL16?DL19?LS1?LS3?LS9?LS10?LS11?DLYS1?DLYS3?LSYS1;(3)Long stemtype: stem length>30 cm,such as the strains of DL2?DL6?DL14?DL17?DLYS2?DLYS4?LSYS4;(4)Large sporophyll type: sporophyll length>30 cm,such as the strains of DL3?DL10?LS4;(5)Earlymaturing type: the sporophytesbeing aging seriously,body length<2.0m,such as the strains of LS6?LS7?LS8?DLYS5?LSYS3;(6)General characteristic type: there being no obvious characteristic of sporophytes,such as the strains of DL7?DL9? DL11?LS2?LS5?LSYS2?LSYS5.The body length,weight,body width,stem length and sporophyll length in large body type of DL8 ? DL18 ? DL13 strains were between 2.85~2.93 m,1.51~1.65 kg,45.4~50.9cm,11.5~23.5cm and 21.2~26.7cm,respectively,showing good economic characters.Cross breeding experiments' results show that: There were no significant difference in maturation rate,fertilized rate of mature eggs and germination rate of fertilized eggs of male and female gametophytes between the hybridizedgroups and control groups(P>0.05).In the hybridization experiments of dominant species,the average length and weight of sporophytes in groups of DL18?×DL13?,DL13?×DL18?,DL13?×DL13?,DL18?×DL18?were 2.5±0.3m and 1.6±0.4kg,2.4±0.3m and 1.5±0.2kg?2.1±0.5m and 1.3±0.4kg?2.2±0.3m and 1.2±0.2kg,respectively,and the sporophytes of hybrid groups showed obvious growth advantage(P<0.05).In the hybridization experiments ofdominant species and local species,the average length and weight of sporophytes in groups of DL8?×DLYS1?,DL8?×DLYS1?,DL8?×DL8?,DLYS1?×DLYS1? were 2.0±0.3m and 1.4±0.2kg ? 1.9±0.3m and 1.3±0.4kg ? 2.1±0.5m and1.5±0.4kg?1.7±0.3m and 1.1±0.4kg,respectively,and the sporophytes' growth of the hybrid groups were significantly faster than that of the local DLYS1 self crossing group,slightly slowerthan that of the DL8 dominant self inbred group.The treatment results of high voltage electrostatic field show that:It was found that the survival rates of the gametophytes were all above 95%,but gradually reduced with the increase of electric field intensity and treatment times;there was no significant difference in maturation rate,fertilized rate of mature eggs and germination rate of fertilized eggs of male and female gametophytes between the treatment groups and control group(P>0.05),contrasted with significant difference in SGR of the gametophytes and the growth of juvenile sporophytes(P<0.05).The average length and weight of F1 generation sporophytes reached the top point of2.4~2.8m and 1.6~2.0kg in treatment groups and 2.2±0.3m and1.2±0.2 kg in control group,respectively,in April.The treated gametophytes and their F1 generation juvenile and adult sporophytes,which in length of 2.2±0.3m and in weight of 1.2±0.2 kg in April,grew best at the electric field intensity of 5.3k V/cm.The rbcL-sp-S sequence analysis showed that these fragments were all above 2100 bp in size;the average content of A+T in the treatment groups and the control group was 64.22%,which was higher than that of the G+C,and the base replacement increased obviously and the base deletion and insertion were also found in the treatment groups;the genetic distance of F1 generation gametophytes between the treatment groups and the control group increased from 0.0024 to 0.0057 with the increase of the electric field intensity,and the genetic distance between the F1 gametophytes and the F2 gametophytes in the control group was0.0033.This research provides data for germplasm improvement and variety breeding of U.pinnatifida in China.