Agriculture Reference
In-Depth Information
Organized at the scale of the continent, population improvement could
easily be expanded to other regions through the leadership of experienced
breeders, aswas the case inLAC in the 1990s. Leading institutionswith the
know-how and appropriate germplasm could develop or improve popu-
lations for the network to proceed to site-speci
c population improvement
targeting their own ecosystems and enhancing particular traits of interest.
Strong interaction between population improvement experts from LAC
and rice breeders in international or national research centers elsewhere
couldhelpcatalyze the adoptionof a generalizedpopulation improvement
approach as the basis for enhancing the use of valuable rice genetic
diversity in any breeding program.
To signi
cantly affect rice production in LAC and possibly other
continents, while having a minimum impact on the environment, we
will have to combine a large number of traits of interest in elite material.
As most of these traits of economic importance are quantitative, genetic
progress can be more easily achieved through population improvement,
incorporating grain yield potential, host plant resistance to the main
pathogens, climate resilience traits, and natural resource use ef
ciency
into synthetic populations managed through recurrent selection. Once
all favorable alleles are included in the pool of genotypes, the best
recombinants are selected in each cycle for line development and for
pursuing the genetic improvement of breeding populations.
Population improvement through recurrent selection is considered
one of the most appropriate breeding tools available for maximizing
genetic gain using natural variation and it should be an integral part of
a productive breeding program. This prebreeding activity developed
through RS is combined with classic pedigree methods for line devel-
opment and the identi
cation of new parental lines. Considering the
principle of population improvement and the possibility it offers for
linking breeding and genetics, recurrent and genomic selections together
could move rice breeding forward with extremely innovative possibili-
ties for ef
cient and rapid rice improvement based on the wide diversity
of the natural variation available within the species.
IV. GENETICS AND GENOMICS APPROACHES TO IMPROVE
RICE BREEDING
Performing modern breeding and ef
cient variety development has always
been a concern for rice breeding in the CIAT Rice Program. Genetic
improvement is about manipulating genes using the natural reproductive
systemof a crop or animal in order to obtain the desired traits in the progeny.
