Improvement of Yield per se in Sugarcane - Translational Genomics for Crop Breeding: Abiotic Stress, Yield and Quality - page 225

Fig. 13.6. Alignment of a chromosome region of sorghum bearing QTLs related
to the regrowth (rectangle) in the linkage group A (LG A) (Paterson et al. 1995) with
the orthologous region in sugarcane chromosome II (SC II) of sugarcane containing
markers (SSCIR 110 and CDSC052 in bold) associated with QTLs for suckering
(from Jordan et al. 2004, 2008 Canadian Science Publishing or its licensors.

C

Reproduced with permission).

Another strategy for tracking down alleles
related to yield components in the very large
sugarcane genome would be to take advan-
tage of the relatively good synteny relation-
ships between sugarcane and diploid grass mod-
els (Glaszmann et al. 1997; Ming et al. 1998;
Jannoo et al. 2007; Le Cunff et al. 2008; Wang
et al. 2010). Ming and colleagues (2002a; 2001)
found syntenic regions between sugarcane and
maize or sorghum that contain QTLs controlling
sugar content, plant height, number of stalks, and
flowering in sugarcane. Like what is shown in
Figure 13.6 using heterologous Restriction Frag-
ment Length Polymorphism (RFLP) probes, Jor-
dan and colleagues (2004) found seven QTL
colocalizations between sugarcane and sorghum
related to tillering and rhizomatousness traits.
These results clearly demonstrate the potential
of allele-tagging strategies based on the exploita-
tion of synteny.
Several studies have used the large Expressed
Sequence Tag (EST) database available for sug-
arcane (Vettore et al. 2003) to develop molec-
ular markers (RFLP, Simple Sequence Repeats

[SSR], and Target Region Amplification Poly-
morphism [TRAP]) showing homology with
candidate genes involved in yield elaboration
(Da Silva and Bressiani 2005; Alwala et al. 2009;
Pinto et al. 2010). This strategy allowed direct
mapping of the genes of interest, as demon-
strated by Da Silva and Bressiani (2005) and
Pinto and colleagues (2010), who described the
development of EST-RFLP markers and found
a sucrose synthase EST-RFLP marker associ-
ated with sugar content in an SP80-180 x SP
80-4966 cross. The sugarcane EST resources
were also the source of the discovery of sin-
gle nucleotide polymorphisms (SNPs) (Grivet
et al. 2003; Cordeiro et al. 2006; McIntyre et al.
2006). The ecotilling strategy that enabled the
discovery of SNP in a target EST was tested
by McIntyre and colleagues (2006) and Aitken
and colleagues (2008) for detecting and mapping
associations with yield components. The whole
genome sequence already available for sorghum,
maize, and rice should improve these strategies
and facilitate the development of accurate candi-
date markers associated with yield.