Genomic selection strategies to increase genetic gain in tea breeding programs

Area of Science:

• Plant breeding
• Agricultural genetics
• Quantitative genetics

Background:

• Tea (Camellia sinensis) is a vital global commodity, primarily cultivated in low- to middle-income countries (LMIC).
• Traditional breeding programs in LMICs face challenges in achieving genetic gain due to low selection accuracy and limited resources.
• Phenotypic selection (PS) is the conventional method, but it has a long generation interval exceeding 16 years.

Purpose of the Study:

• To evaluate the potential of genomic selection (GS) for enhancing genetic gain in tea breeding programs.
• To compare the efficiency and cost-effectiveness of different GS implementation strategies against traditional PS.

Main Methods:

• Stochastic simulations were employed to model and compare four breeding programs: one PS program and three GS-based programs.
• The PS program simulated a 40-year commercial tea breeding cycle.
• Key performance indicators included genetic gain, selection accuracy, and generation interval.

Main Results:

• All simulated GS programs yielded at least 1.65 times higher genetic gains compared to the PS program.
• The Seed-GS (Seed-GSc) strategy proved most cost-effective, achieving higher accuracy early and reducing the generation interval to 2 years.
• The Seed-Pedigree (Seed-Ped) program, a non-GS alternative, improved gains by 1.2 times over PS.

Conclusions:

• Genomic selection offers a powerful tool to accelerate genetic progress in tea breeding, even within cost-constrained LMIC programs.
• GS implementation can significantly increase genetic gain per unit of time and cost.
• The Seed-GS strategy is recommended for its cost-effectiveness and early-stage accuracy improvement.