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

Screening for Brown spot
One thousand eight hundred (1800) entries comprising
NSN 1, NSN 2, NHSN, DSN, Germplasm, advance
breeding lines and some resistant donors were
screened for brown spot resistance. Thirteen hundred
entries were susceptible, 354 moderately resistant and
146 (CR2641-26-1-2-2, CR2644-2-6-4-3-2, CR2652-14,
CR2683-15-5-3-1-1, CR2389-5-2-1-1, CR758-16-6,
CR2643-1-4-3-1, CR2429-5 et.) showed resistant reaction
to brown spot in the nursery. Out of 244 entries
from the F 6
population of the cross Kalinga III/
Moroberekan, 26 entries showed resistance reaction,
96 entries were rated as moderately resistant and 122
were susceptible against brown spot.
Breeding for Resistance to Major Insects
Breeding for multiple pest resistance with
emphasis on brown planthopper (BPH),
yellow stem borer (YSB) and gall midge (GM)
Hybridization for new cross combinations
In order to incorporate both BPH and YSB resistance,
five uniform advanced breeding lines for BPH resistance
viz., CR2711-76 (Tapaswini/Dhobanumberi),
CR2711-114 (Tapaswini/ Dhobanumberi), CR2711-139
(Tapaswini/Dhobanumberi), CR2711-149
(Tapaswini/ Dhobanumberi) and CR2712-12 (Samba
Mahsuri/Salkathi) which were found to be promising
in AICRIP PHS trial, were used in the crossing
programme with Nalihazra and Ramaboita as resistant
donors for YSB resistance.
Cross seeds of multiple cross combinations involving
elite cultivars viz., Swarna, Samba Mahsuri,
Tapaswini, Pusa 44, Pooja and Naveen, resistant donors
for BPH viz., Salkathi and Dhobanumberi; and
resistant donors for YSB viz., Nalihazra and Ramaboita
were grown and F 2
seeds were harvested.
Observational yield trial
Thirty two selected uniform advanced breeding lines
for BPH resistance and 24 selected uniform advanced
breeding lines for gall midge resistance were grown
with suitable checks under observational yield trial.
Data relating to yield attributing characters were recorded.
The lines were harvested and post harvest processing
data recording was done. From the breeding
lines for BPH resistance, three lines belonging to
Tapaswini/Salkathi and Pooja/Dhobanumberi crosses
performed better compared to the checks whereas, from
breeding lines for gall midge resistance four lines belonging
to Tapaswini/Phalguna and Swarna/Sarasa
crosses performed better as compared to the checks.
Generation advancement and further
selection
From the breeding lines grown for generation advancement,
20 and 15 single plants were selected from
BPH and gall midge resistance crosses, respectively
basing on the desired agro-morphological traits and
yield attributing characters. The lines were harvested
with recording of agro-morphological data.
Screening for BPH and gall midge resistance
For confirmation of resistance 60 advanced breeding
lines from the crosses for BPH resistance and 43
advanced breeding lines from the crosses for gall midge
resistance were screened in the net house for BPH and
gall midge resistance respectively under artificial insect
pressure. Five lines showed high degree of resistance
for BPH and eight lines showed high degree of
resistance for gall midge as per IRRI SES scale. Resistant
plants were recovered from the screening and were
grown in the net house. The seeds of these recovered
resistant plants were collected separately.
Development of molecular markers linked to
genes for resistance to brown plant hopper
In order to identify molecular markers linked to BPH
resistance, the mapping population (F 2
) is being developed
from the cross between resistant parent, Salkathi
and susceptible parent, Swarna. Selfed seeds were collected
from 200 individual F 2
plants during December,
2011. Phenotyping of the 125 F 3
population was done
under artificial infestation during March-April, 2012.
Percentage of survival was counted on 5 th , 6 th and 7 th
day after release when 100% TN1, the susceptible check,
died. Six F 3
lines showed resistant reaction with SES
score of three while 17 showed moderately resistant
reaction with SES score of five. Thirty seven lines
showed susceptible reaction with SES score of seven
while 65 showed highly susceptible reaction with SES
score of nine. Salkathi showed SES score of three and
TN1 showed SES score nine. A total of 518 microsatellite
primers from twelve chromosomes of rice were used to
scan genomes of susceptible cultivar, Swarna and resistant
cultivar, Salakathi. One hundred fourteen primers
(22%) revealed polymorphism between parents. The
polymorphic primers varied from 8.82% (Chromosome
9) to 33.33% (Chromosome 11).
42 CRRI ANNUAL REPORT 2011-12