Improvement of Yield per se in Sugarcane - Translational Genomics for Crop Breeding: Abiotic Stress, Yield and Quality - page 211

Chapter 13

ImprovementofYield per se in Sugarcane

M.Gouy,S.Nibouche,J.Y.Hoarau,and L.Costet

Abstract

Sugarcane is the main source of sucrose in the world and has also become one of the main sources
of renewable energy, thanks to ethanol and electricity production. The main objectives of breeding
programs are improving cane biomass and qualities. The genetics of current sugarcane cultivars
( Saccharum spp.) are extremely complex, owing to a high polyploid genome of 10 to 12 homeologous
chromosome sets, resulting from the interspecific origin of two polyploid ancestral genomes. A century
of breeding efforts based on elite domesticated progenitors improved by wild introgressions has helped
build one of the most productive biomass crops. However, in recent decades the percentage increase
in annual sugarcane yield has been lower than in other crops. Until now, cultivar improvement has
relied on traditional breeding programs that require 12 to 15 years of expensive field evaluations. This
article discusses the most recent advances in genomics applications to support traditional breeding.
In the past two decades, efforts have been made to construct genetic maps, study quantitative trait
loci (QTL), and start association mapping studies. Today, genomic selection (GS) approaches to
select individuals for advancement in the breeding process is believed to be appropriate for complex
traits such as yield, thanks to improved estimates of marker effects combined with a better grasp
of small-effect QTLs. GS is particularly attractive in the highly polyploid context of sugarcane,
where the nature of yield genetic determinism is presumably highly quantitative. Frequent genotype x
environment interactions add to the challenges associated with QTL detection. The focus in this
article is on research areas that are likely to result in concrete improvements through advancing the
incorporation of association genetics-based approaches. A strategy to design a breeder-friendly marker
system is also presented. Plant growth modeling could provide sounder ecophysiological parameters
for describing the complex biological process underlying yield and sucrose elaboration. Such models
could overcome traditional problems caused by G x E interactions and consequently improve both
QTL detection and GS approaches.

Introduction

using stem cuttings. Sugarcane is cultivated
with one plant crop and several ratoon crops,
each about 12 months in length after an annual

Sugarcane is a giant perennial grass two to four
meters in height that is propagated clonally