Agriculture Reference
In-Depth Information
varieties with optimal performance under stress conditions and increased
sustainability of low-input agroecosystems. Unveiling these processes and
associated genetic elements related to P physiology is extremely important
and urgent in order to produce genotypes with enhanced root exudation
and phosphate mobilization specifi cally in low-P conditions.
11.5 SCIENTIFIC AND NON-SYSTEMATIC ADVANCES: BREEDING
STRATEGIES AND CONCEPTS
Low-input systems create a unique and complex environment, which are
often composed of multiple factors limiting yield, making high yields dif-
ficult to achieve. However, low-input systems encompass a more sustain-
able agriculture due to improved management of on-farm resources. By
increasing the availability of varieties that perform well under low-input
conditions, the potential to meet the production demands of forthcoming
populations could significantly be improved. By shifting breeding and se-
lection methods toward low-input conditions and by making better use of
local natural genetic variability, varieties that are best suited genetically
and able to respond accordingly when exposed to stress conditions can
improve the management of valuable, finite resources, as well as poten-
tially decrease the energy used to produce sufficient quality food to people
around the world. Several selection strategies could be successfully im-
plemented to improve low-input breeding programs, such as participatory
breeding [147-149]. It is important to notice, nonetheless, that the wide
variety of cultural practices common to low-input production systems can
create challenges for breeders.
Most new breeding strategies are built on the idea of natural selection.
Allard and Hansche [150] originally stated that natural selection identifi es
superior crop genotypes, which make up a greater portion of the popu-
lation in over time. After many generations, natural selection produces
genotypes well suited to unpredictable and stressful environments that are
common to low-input systems [151]. By breeding under high-input condi-
tions, the opportunity to exploit advantageous genetic differences at low
input levels is lost, resulting in exclusion of important alleles needed to
provide adequate and superior varieties [38]. Ceccarelli [38] suggested the
