Agriculture Reference
In-Depth Information
made it possible to mix production from the uplands with the now pre-
dominant product from the irrigated system. Higher yield potential and
lodging resistance, coupled with high-input crop management in favor-
able climatic conditions, made it possible to achieve yields of 5
6tha
1
-
in the uplands, earlier conceivable only with
flood irrigation.
2. Landmark Upland Rice Cultivars in Brazil.
The IAC (Instituto Agro-
nômico de Campinas) started the
first upland rice breeding program
in Brazil in 1938, developing cultivars based on Brazilian landraces
and exotic materials. Cultivars IAC 25 and IAC 47 played a fundamental
role in the settlement of the Cerrado region in central Brazil, as upland
rice was widely used as a pioneer crop on the agricultural frontier in the
1960s and 1970s. In the 1980s, those cultivars were largely replaced
by Embrapa
s cultivars, derived from crosses between IAC cultivars and
63-83, a line introduced in Africa by collaborators from IRAT (currently
known as CIRAD). Embrapa cultivars Guaraní and Rio Paranaíba pre-
sented higher blast resistance and drought tolerance than older cultivars,
and for this reason they were better adapted to the tropical uplands.
In the 1990s, the Brazilian ricemarket preference turned to long-slender
grains, typical of irrigated rice cultivars. In response, Embrapa incorpo-
rated new variability in its program, including new materials from IAC
and premium-quality cultivars from the United States, eventually releas-
ing Primavera, which set a new standard for rice cooking quality in
Brazil. Unlike most irrigated cultivars, Primavera grains remain soft after
cooling, due to its intermediate amylose content (AC), whereas most
irrigated cultivars have high AC, resulting in starch retrogradation. In
modern urban society, rice is often reheated in a microwave oven and
thus this characteristic is important for consumers.
There was a large in
'
s
rice breeding program in the 1990s. That germplasm included wide
hybridizations, bringing
indica
genes into a predominantly
japonica
background. The result was a signi
ux of germplasm from CIAT into Embrapa
'
cant increase in yield potential and
lodging resistance, especially under favorable upland conditions.
Despite their clear agronomic superiority, a perceived setback in grain
quality limited the adoption in Brazil of cultivars deriving directly from
introgressions from CIAT.
Primaverawas surpassed inmarket shareonlybyvarietyANCambará,
released by the private sector (Agronorte, Sinop, Brazil). This was
the
first variety to combine grain quality comparable with that of
Primavera with higher lodging resistance, allowing cultivation in rainy
regions under higher inputs. However, AN Cambará is highly suscepti-
ble to drought and blast pressure, which makes it less resilient to
