Central Rice Research Institute Annual report...2011-12

Introgression with DTY 1.1
and DTY 2.2
QTLs
into IR64-Sub1 for drought tolerance
Backcross populations (BC 1
F 1
s) of two crosses viz.,
IR64-Sub1/IR88287-367-B-B and IR64-Sub1/ IR86918-
B-305 were raised during 2011 wet season at CRRI Regional
Station, Hazaribag. A total of 50 plants from each
cross phenotypically similar to recurrent parent were
selected for foreground selection. Two markers (RM279
and RM236) linked to QTL DTY 2.2
and four markers
linked to QTL DTY 1.1
(RM3825, RM315, RM212 and
RM431) were selected for foreground selection. Among
these primers RM3825 and RM279 have given clear
polymorphism for DTY 1.1
and DTY 2.2
, respectively. Out
of 50 plants selected for foreground selection, 8 plants
of IR64-Sub1*2 /IR88287-367-B-B and 10 plants of IR64-
Sub1*2/ IR86918-B-305 have been confirmed for the
target marker.
Stress Tolerant Rice for Poor Farmers
of Africa and South Asia (STRASA)
Drought prone rain-fed rice areas
Observational yield trial (OYT)
The trial was conducted under rainfed upland condition
consisting of 105 entries and five checks (Kalinga
III, Vandana, Anjali, CRDhan 40 and Brown gora). The
promising entries identified were CRR423-2-2-1-1,
IR83929-B-B-132-3, IR87756-20-2-2-3 and CRR660-2.
Advance Yield Trial (80-100 Days)
Twenty five genotypes along with check varieties
Anjali, Vandana and Brown gora (local check) were
evaluated under two fertility conditions (low and high)
following alpha-lattice design with three replications
under rainfed uplands. The low fertility treatment received
a fertilizer dose of NPK @ 40:30:20 and for high
fertility treatment fertilizer dose is NPK @ 60:30:20. All
other crop management factors were applied uniformly
to both trials and manual weeding was done twice to
control the weeds. During the season, the crop was not
limited by moisture due to normal and uniform distribution
of rainfall. Average grain yield across all cultivars
was 27% lower in low fertility than in high fertility
condition (1871 vs. 2573 kg ha -1 ). Six advanced breeding
lines were significantly better than traditional variety
Brown gora in low fertility condition. The promising
entries across the fertility levels based on yield and
maturity duration are CRR617-B-3-3, CRR646-B-93-6-
B-3, CRR428-237-1-3-1, BAU446-06 and IR78908-193-
B-3-B.
Advanced Yield Trial (100-120 Days)
A set of varieties, advanced lines (75) of 100-120
days maturity duration group were evaluated under
rainfed natural stress (RNFDS), rainy season managed
drought stress (RSMDS) and also under control condition
in three reps trial following alpha-lattice design.
Drought intensity index (DII) was 0.41 for the rainfed
trial and 0.54 for the managed stress trial, which indicates
moderate level of stress. The breeding lines
IR84899-B-182-CRA-12-1, IR83381-B-B-137-3, IR83387-
B-B-40-1, CB-05-753 and CRR626-B-41-4-4-B yielded
about 3.0 t ha -1 under stress and more than 6.0 t ha -1
under control condition. These lines combine yield
potential at par with the widely grown irrigated varieties
like MTU 1010, IR 64 and perform much better reproductive
stage stress.
Drought OYT or collaborative nursery
To provide a rapid preliminary evaluation of drought
tolerance a set of 225 promising breeding lines were
evaluated under managed stress and control conditions.
IR87751-20-3-2-1 (2.23 t ha -1 ), CRR625-B-88-3-4
(2.0 t ha -1 ), IR87753-11-2-1-2 (1.77 t ha -1 ) and IR87761-
48-1-3-2 (1.77 t ha -1 ) performed well under very severe
stress l conditions, and promoted for advanced yield
testing. Out of 14 potential donors evaluated for reproductive
stage drought tolerance, Kalia (1.95 t ha -1 ) and
Djogolon (1.99 t ha -1 ) were promising.
Drought Breeding Network- Phase 2
Evaluation of Vandana NILs for drought
Seven qDTY12.1 NILs in the Vandana background
along with parents were evaluated under managed
stress (rain-out shelter) and normal field condition in
direct seeded uplands. In the trial conducted under rainout
shelter stress was imposed at 50 days after seeding
and in normal field there was no stress because of uniform
rainfall distribution. There was severe stress in
the rainout shelter (-70 kpa at 15 cm and -30 kpa at 45
cm depth) as indicated by the tensiometer reading. Best
NIL, IR84984-83-15-481-B out yielded the recurrent
parent Vandana by 27% under stress condition and
difference was non-significant under non-stress condition
(Table 24).
Submergence and Flood prone areas
Evaluation of entries under Observational Yield Trial (OYT)
Eighty entries from different cooperating centers
under Eastern India Rainfed Lowland Shuttle Breeding
Network (EIRLSBN) were evaluated for grain yield
and its associated components in an augmented block
56 CRRI ANNUAL REPORT 2011-12