Abstract
Genomic selection (GS) can improve the efficiency of tea breeding
compared to phenotypic selection (PS) by shortening the generation
interval, increasing selection accuracy, and shortening the duration of
the entire breeding program, especially at early stages. Tea (Camellia
sinensis (L.) O. Kuntze) is mainly grown in low- to middle-income
countries (LMIC) and is a global commodity. Breeding programs in these
countries face the challenge of increasing genetic gain because the
accuracy of selecting superior genotypes is low and resources are
limited. Recurrent phenotypic selection has traditionally been the
primary method for developing improved tea varieties and can take over
16 years. Therefore, the main objective of this study was to investigate
the potential of implementing GS in tea breeding programs to speed up
genetic progress despite the low labour costs in LMIC. We used
stochastic simulations to compare three GS breeding programs with a
commercial PS program over a 40-year breeding period. All GS breeding
programs achieved higher genetic gains compared to PS. Seed-GSconst, in
particular, proved to be the most cost-effective strategy for
introducing GS into tea breeding programs. It introduces GS at the
nursery stage, thereby increasing the predictive accuracy at the early
stage of the breeding program. It also shortens the duration of the
entire breeding program by three years and reduces the generation
interval to two years. Our results indicate that GS is a promising
strategy to improve genetic gain per unit time and cost in tea breeding
programs.