Biology Reference
In-Depth Information
colleagues in Chapter 10 provide a compre-
hensive overview on biofortification in maize
and highlight two specific cases of genetic
improvement in maize that resulted in high
nutritional value, particularly with respect to
essential amino acid content in the endosperm.
Besides emphasizing the molecular marker-
assisted QPM (quality protein maize) breeding,
the chapter also throws light on its impact in
the developing world. Furthermore, the essence
of provitamin A, Fe, and Zn, and low-phytate
content, and the possibilities for genetically
engineered, high-lysine maize are elegantly dis-
cussed in the chapter.
Peanut is the most important food legume
and oilseed crop cultivated in arid and semi-
arid regions of the world. About 45-51% of the
dry weight of peanut seeds is oil (Chamberlin
et al. 2011). Among fatty acids, oleic and linoleic
acids are major fatty acids that determine the
oil quality; hence the ratio of the two, the O/L
ratio, is critical. In Chapter 11, molecular breed-
ing efforts aimed at improving the oil quality in
peanut, undertaken at the Kazusa DNA Research
Institute and the Chiba Prefectural Agriculture
and Forest Center, both located in Japan, is dis-
cussed by Kolikonda and colleagues. This chap-
ter also provides the cost comparisons (costs
involved) of conventional and molecular breed-
ing programs.
The cultivated tomato, the most popular
vegetable crop in the world, is an important
model system for genetics and genomics stud-
ies. Marker-assisted selection has been employed
extensively in tomato breeding for improving
many simple traits. Kinkade and Foolad in Chap-
ter 12 look for QTL analysis approaches and
focus on the use of new “omics” technology and
its potential use for improving fruit quality in
tomato breeding. Progress on reverse genetics
approaches, such as TILLING and the bioin-
formatic workflows to handle high-throughput
identification of mutations in candidate genes are
discussed.
In sugarcane, up until two decades ago most
of the breeding efforts for improvement were
purely traditional. Chapter 13, by Gouy and col-
leagues, highlights recent advances in genomics
and its applications for enhancing sugar yields.
The chapter also highlights the ongoing efforts
on genomic selection (GS) for enhancing yield
gains in sugarcane.
Summary and Outlook
This volume presents a number of comprehen-
sive and informative articles written by eminent
scientists in the area of crop genomics and molec-
ular breeding. It is important to mention here that
the traits and crops discussed in this volume pro-
vide just some examples on how genomics can
help facilitate the enhancement of tolerance to
abiotic stresses and quality in crops.
Volume I of this series offers comprehensive
reviews of biotic stress tolerance in a range of
crops. As compared to the selected examples
of GAB for biotic stress tolerance, it is clear
that although rice has made significant progress
in GAB for abiotic stress tolerance, most
success stories of GAB are related to biotic
stresses. This may be attributed to the partially
qualitative inheritance and higher heritability of
disease resistance as compared to abiotic stress
tolerance. Similar to submergence tolerance, if
the QTLs contribute higher phenotypic variance,
GAB approaches such as MAS and MABC can
be deployed in breeding programs. However,
in the case of tolerance to abiotic stresses and
yield, where several and small-effect QTLs are
involved, simple molecular breeding approaches
such as MABC and MAS are not as effective. In
those cases, MARS (Bernardo and Charcosset
2006) and GS (Heffner et al. 2009, 2010, 2011;
Heslot et al. 2012; Nakaya and Isobe 2012) are
expected to be the most promising approaches.
In this context, and in addition to biparental
linkage mapping, mapping approaches such
as genome-wide association studies (GWAS;
Huang et al. 2010; Zhao et al. 2011; Li et al.
2012; Pasam et al. 2012) and nested asso-
ciation mapping (NAM; Hung et al. 2011;
Kump et al. 2011; Cook et al. 2012) can be
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