June 04, 2020

1. Introduction to the problem

Crop by region

ICRISAT Sorghum (Sudan Zone)

Problem specification

Curently, we use on average 15 new parents each year to generate 30 crosses with 200 progeny each (6000 individuals in total)

Breeding strategy component tackled

Crossing

Breeders' equation terms tackled

i, (r)

Ha vs H0

Changing the number of parents / crosses and progeny per cross will significantly increase genetic gain vs. The current number of parents, crosses and progeny per cross is already in the optimal range.

2. Materials and methods

Data

Breeding scheme was provided by the breeding team.

Treatments

Treatment Description
T1 Current crossing scheme: 15 parents, 30 crosses and 200 progeny per cross
T2 15 parents; 40x150, 50x120 and 60x100 crosses
T3 All combinations generating 5900 to 6000 individuals per year
- Parents 10, 12, 14, … , 58, 60
- Crosses 10, 12, 14, … , 98, 100
- Progeny 100, 110, 120, … , 240, 250


Simulation procedure

Current breeding scheme was used as baseline. All possible combinations with 5900 to 6000 individuals per year were compared

3. Results

Best scenarios

Scenario gainF2 nParents nCrosses nInd nIndTotal
10 Scn80 60.83962 12 54 110 5940
5 Scn157 60.81919 10 44 130 5720
2 BL_60 60.47350 15 60 100 6000
9 Scn79 60.45550 10 54 110 5940
7 Scn209 60.38126 10 42 140 5880
1 BL_40 60.33859 15 40 150 6000
3 Scn131 60.23394 10 50 120 6000
8 Scn28 60.22726 12 60 100 6000
6 Scn184 60.21400 12 46 130 5980
4 Scn132 60.21340 12 50 120 6000

Worst scenarios

Scenario gainF2 nParents nCrosses nInd nIndTotal
10 Scn51 56.49115 58 60 100 6000
3 Scn129 56.47888 58 48 120 5760
6 Scn26 56.47509 60 58 100 5800
2 Scn104 56.45791 60 54 110 5940
8 Scn284 56.43012 56 40 150 6000
5 Scn234 56.32634 60 42 140 5880
9 Scn286 56.31910 60 40 150 6000
4 Scn182 56.30467 60 44 130 5720
1 Scn103 56.28977 58 54 110 5940
7 Scn260 56.14437 60 38 150 5700

Gain over 30 years of breeding

4. Conclusion

We accept H0: The current crossing scheme is already in the optimal range.

However, we recommend to increase the number of crosses per year - e.g. 40 crosses with 150 progeny each