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

crossing. CRMS31A and CRMS32A were multiplied in
larger quantity both during wet season and dry season,
2011 (>100 kgs each). Five CMS lines from other
sources (APMS6A, RTN12A, RTN6A, PMS10A, and
PMS15A) were taken up for small scale multiplication
for further utilization. Six CMS lines including the
widely used lines, CRMS31A and CRMS32A were
grown for purification and seed multiplication during
dry season, 2012.
Transfer of characters into CMS lines
Hybrids were developed with donors for exserted
stigma and BLB resistance with CRMS31B, CRMS32B
and IR42266-29-3R, to transfer these traits into the
promising CMS and restorer backgrounds. BC 3
F 2
and
BC 2
F 2
progenies of these crosses were grown and were
tested for presence of genes of interest. Test crosses with
some promising BC 2
F 2
single plants having resistance
genes and without fertility restorer genes were made
and the resultant hybrids were found to be sterile and
backcrosses were initiated on these sterile F 1
s.
Backcrosses were continued with exserted stigma
segregants by using them as male parents on two CMS
lines, CRMS31A and CRMS32A to transfer exserted
stigma trait and develop improved CRMS31A and
CRMS32A.
Status of back crossing to develop new CMS
lines
Sixty nine backcross derived lines in 105-140 days
duration were evaluated and carried forward based on
pollen/spikelet sterility. Some of the short duration
advanced lines involving drought tolerant recurrent
parents like Virendra and Sahabhagidhan were quite
stable for pollen and spikelet sterility. Some of the promising
lines with stable male sterility, out crossing, good
floret opening, and panicle and stigma exsertion are
listed in Table 10.
Seed production of hybrids
Hybrid seeds of 13 combinations were produced
including the three released hybrids during wet season,
2011 and dry season, 2011. Flowering behavior
and synchronization of nine long duration hybrid combinations
were studied. Production of eight hybrid combinations
was taken up during dry season, 2012. Flowering
behavior and synchronization of six long duration
hybrid combinations studied during wet season,
2011 was also taken up during dry season, 2012. Three
long duration hybrid combinations were nominated for
evaluation in SLHRT-2011 at sixteen locations during
wet season, 2011.
Restorer and maintainer breeding
About 1200 single plant progenies from both population
improvement and recombination breeding (42
cross combinations) were grown in pedigree nursery
and single plant selections with desirable features were
made to develop improved parental lines.
Doubled haploid breeding
A total of 495 regenerants were produced from the
anther culture of Rajalaxmi and they were transferred
to pots and were grown in the green house in the A 0
generation. The ploidy analysis of the regenerants revealed
that of the 495 derivatives, 243 double haploids
and 221 were halpoids while the rest were polyploids.
Table 10. Promising sterile backcross derived lines advanced during 2011
BCN No. Recurrent parent Characteristics
BCN 5 12A HR-26-73 -
BCN 5 17A HR-34-7 -
BCN 5 39A CR-2234-75 -
BCN 4 52A PS 92B(69) (Kalinga) Purple leaf
BCN 4 71A CRMP 2-1-614(79) -
BCN 4 166A Shatabdi Short duration
BCN 4 206A Abhishek Short duration, drought tolerant
BCN 4 199A CR2234-1020 (WA) Good floret opening
BCN 4 200A CR2234-1020 (Kalinga) Good floret opening
BCN 2 99A A-180-12-1(87) Short duration, drought tolerant
BCN 4 187A Sahabhagidhan Short duration, drought tolerant
BCN 4 180A CR2234-834(WA) Good floret opening and stigma exsertion
30 CRRI ANNUAL REPORT 2011-12