Combining Ability Analysis On Major Agronomic Traits In Castor Plant

Based on heterosis group devision,the combining ability of 10 target traits were analyzed using the parents,selected from 101 backbone ones,and their derived F₁generation.The main results are as follows:1.Among 101 parents,the variance coefficients of 11 continuous quantitative traits ranged from 10.28 to 64.24%,with an average of 35.84%.The genetic diversity index of the 15 traits ranged from 4.418 to 4.610,with an average of 4.545.2.A total of 328 alleles were amplified within 101 parents by 58 pairs of SSR primers,4-12 alleles were identified by each pair of primers,with an average of 5.655.The Polymorphism information content（PIC）ranged from 0.532 to 0.844,with an average of 0.731.As a result,101 parents were divided into 5 heterosis groups.3.In the 1×11 incomplete diallel cross experiment in 2019,the general combining ability（GCA）of parents（top 5）was in the follows order:（1）Plant height:B13-1>B1-3>B11-1>B27-6>B63-5（Reverse order）;（2）Bearing height of primary raceme:MSBK-3>B63-5>B11-1>B6-6>B13-1（Reverse order）;（3）Stem diameter:AS-20>MSBK-3>GD-9>B63-5>A3-2;（4）Number of effective branches:B63-5>AS-20>MSBK-3>B13-1>SD-21;（5）Number of effective spikes:B63-5>MSBK-3>AS-20>B13-1>SD-21;（6）Number of capsules in primary raceme:B13-1>AS-20>A3-2>B27-6>B6-6;（7）Hundred-grain weight:GD-9>B46-4>B6-6>B11-1>A3-2.4.In the 3×18 incomplete diallel cross experiment in 2020,the GCA of parents（top 5）was in the follow order:（1）Emergence period:FG-4 was the best in pintillate lines,FG-1 and MD-1were the best in monecious lines;（2）Emergence rate:YB-5>AS-1>B1-3>YB-3>GD-8;（3）Stem diameter:YB-5>TG-2>YB-3>B1-2>GD-9;（4）Bearing height of primary raceme:FG-1<TG-2<B6-6<FG-3<SD-12（Reverse order）;（5）Node number of main stem:AS-1>B1-3>GGB-1>FG-2>YB-3;（6）Number of effective spikes:B1-3>B2-2>B1-2>YB-3>B13-1;（7）Number of capsules in primary raceme:B1-3>YB-5>B13-1>SD-22>YB-3;（8）Number capsule of first branch:YB-5>B6-6>B13-1>FG-2>YB-3;（9）Bearing length of primary raceme:B1-3>FG-2>YB-5>B13-1>SD-10;（10）Fruit length of first branch:SD-21>FG-2>B13-1>SD-10>YB-5.The special combining ability of combination（top 5,descending order）were:（1）Emergence period:FG-4×FG-1,FG-4×MD-1;（2）Emergence rate:FG-4×SD-10,FG-4×GGB-1,GGB-1×GD-9,YB-3×FG-1,YB-3×B13-1;（3）Stem diameter:SD-21×B2-2,FG-4×SD-22,FG-4×TG-2,YB-3×B13-1,YB-3×GD-9;（4）Bearing height of primary raceme:FG-4×B13-1,SD-21×FG-2,SD-21×SD-10,YB-3×B1-2,YB-3×MD-1;（5）Number of effective spikes:SD-21×B2-2,YB-3×B1-3,YB-3×B13-1,FG-4×FG-3,FG-4×SD-22;（6）Number of capsules in primary raceme:YB-3×B13-1,FG-4×SD-22,SD-21×B1-2,SD-21×MD-1,YB-3×B1-3;（7）Node number of main stem:FG-4×GD-9,FG-4×B13-1,SD-21×GD-8,YB-3×B1-2,YB-3×SD-12;（8）Number capsule of first branch:SD-21×B6-6,YB-3×FG-2,FG-4×FG-3,SD-21×SD-10,YB-3×GD-8;（9）Bearing length of primary raceme:SD-21×YB-5,FG-4×SD-22,YB-3×B13-1,YB-3×B2-2,FG-4×FG-2;（10）Fruit length of first branch:FG-4×B13-1,SD-21×B6-6,SD-21×FG-1,FG-4×FG-3,YB-3×B2-2.5.Stem diameter,bearing height of primary raceme,effective spike per plant,capsule number of main spike,node number of main stem,length of main spike and length of primary spike all posessed a high broad heritability（h _B²%,69-79%）,and medium narrow heritability（h _N²%,30.1-58.3%）.Although the capsule number on 1st branch spike,seedling emergnce rate and seedling emergence stage all performed a high h _B²%（77.63%,78.92%,76.54%）,the h _N²%was low（30.1%,27.4,5.06%）.