A REVIEW OF GENETIC GAIN IN SUGARCANE BREEDING USING GENOMIC SELECTION IN DIFFERENT COUNTRIES

Abstract

Sugarcane is an industrial crop cultivated in tropical and subtropical regions of the world. It is an emerging source of sustainable bioenergy, accounting for more than 70% of world sugar consumption. The increase in productivity from sugarcane has been small compared to other major crops, and the rate of genetic gains from current breeding programs tends to be plateauing. In this review, some of the main contributors for the relatively slow rates of genetic gain are discussed, including (i) breeding cycle length and (ii) low narrow-sense heritability for major commercial traits, possibly reflecting strong non-additive genetic effects involved in quantitative
trait expression. A general overview of genomic selection (GS), a modern breeding tool that has been very successfully applied in plant breeding, is given. This review discusses key elements of GS and its potential to significantly increase the rate of genetic gain in sugarcane, mainly by (i) reducing the breeding cycle length, (ii) increasing the prediction accuracy for clonal performance, and (iii) increasing the accuracy of breeding values for parent selection. GS approaches that can accurately capture non-additive genetic effects and potentially improve the accuracy of genomic estimated breeding values are particularly promising for the adoption of GS in sugarcane
breeding. Finally, different strategies for the efficient incorporation of GS in a practical sugarcane breeding context are presented. These proposed strategies hold the potential to substantially increase the rate of genetic gain in future sugarcane breeding.