Agriculture Reference
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and improved tolerance of blast, sheath spot, low temperatures, and
grain shattering (Molina et al. 2011).
Indica. Temperate conditions restrict the wide adaptation of indica
germplasm in Uruguayan rice crops. However, there are examples of
very successful high-yielding cultivars released by public research as a
result of local selection. Indica variety El Paso 144 (Chebataroff et al.
1987), selected in a population introduced from CIAT, has been the most
important variety in the period 1995
2010 (with about two-thirds of the
crop area). Together with INIA Olimar (Blanco et al. 2004), both have
occupied
-
80% of the rice area in recent years. Current breeding efforts
focus on (1) improving blast resistance in the genetic background of
those cultivars by MAS (tracking Pi-2 and Pi-33 genes), (2) conferring
cold tolerance at the vegetative stage for early planting (in partnership
with FLAR), (3) adapting high-yielding lines that outperform the afore-
mentioned cultivars, and (4) closing the milling and cooking quality gap
between tropical japonica and indica germplasm. L5903, an advanced
high-yielding long-season line with high blast resistance, will be vali-
dated in farmers
>
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field testing
among 360 new local experimental lines, four blast-resistant cultivars
yielded
fields in the next season. After 3 years of
12 t ha 1 , 14% more than the checks El Paso 144 and INIA
Olimar (Pérez de Vida et al. 2011).
>
eld and Related Germplasm. Concern about the spread of
Clear
red
rice
has resulted in an increasing use of introduced imidazolinone-
tolerant cultivars and hybrids, which were grown on 9% of the crop area
in 2012
2013 (Inov CL 5.4%, Puitá INTA CL 2%, Gurí INTA CL 1.1%,
and CL244 0.4%). Tolerant germplasm developed by Louisiana State
University was introduced under research agreements with BASF, and
was used in selection and in crosses with local germplasm, of either
indica or tropical japonica background (Blanco et al. 2007). Currently,
two cultivars developed by INIA, CL244, and CL212 are in validation in
farmers
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fields before their eventual release. In experiments conducted
between 2006
'
2012, the grain yield of CL244 was 10%
higher than that of Puitá INTA CL, with shorter growth duration and
excellent cooking quality, but it is blast-susceptible. CL212 had a more
limited yield advantage (6%) but was blast-resistant (Blanco et al. 2012).
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2007 and 2011
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Special Quality. Breeding efforts toward special grain quality rice
started early in the 1990s, focusing on premium-quality short grains.
Initial activities involved introductions of temperate japonica germ-
plasm from Japan, Korea, Italy, Spain, and the United States. The
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