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

survey with additional 116 hyper variable microsatellite
primers indicated that 69 were polymorphic between
WAB 50-56 and CR662-2211-2-1 (per se yield), 37 were
polymorphic between PDKV Shriram and Heera (grain
number) while 64 were polymorphic between AC 38562
and Pimpudibasa (1000 grain weight).
QTL associated with root-knot nematode
resistance in the rice variety Ramakrishna
Phenotyping and genotyping of 109 F 9
recombinant
inbred lines from the cross Annapurna/Ramakrishna
identified three QTLs associated with root-knot nematode
resistance in the rice variety Ramakrishna with a
LOD score>3.0 (Table 20).These loci were designated
as QMg1 (t), QMg2 (t) and QMg3 (t). QMg1 (t), located
at 13.7cM on short arm of Chromosome1, control production
of galls on roots, production of eggs by the
pathogen and compensatory mechanism of the host,
together explaining 41.24% of phenotype variance.
QMg2 (t), located at 23.7cM on short arm of chromosome2,
involved in production of galls by the pathogen
on roots, contributing 7.05% to phenotype variance.
QMg3 (t), located on short arm of chromosome3 at 21cM
was involved in gall and egg production by the nematode,
explaining 78.73 % of phenotype variance for the
two traits together. All the three traits were highly correlated.
Identification and deployment of genes
imparting phosphate utilization in upland rice
Fourteen rice varieties such as IR36, Kalinga III,
Vandana, Virendra, UpLPi7, Anjali, Rasi, Annada,
CRDhan 40, Sadabahar, Hazaridhan, Sahabhagidhan,
Abhishek andAzucena were screened for phosphorus
deficiency tolerance using sand culture. The plants were
subjected to stress (nutrient solution containing 4 and
8 ppm of P) and non-stress (nutrient solution with 16
ppm of P) conditions. Reduction was observed for all
the four traits (i.e. plant height, root length, number of
roots/plant and dry weight/plant) at low P (4 ppm)
and medium P (8 ppm) as compared to normal P (16
ppm). Least reduction was observed for all the traits in
Rasi and Abhisek while reduction was highest for all
the traits in IR36 and UPLPi7. Based on the four agronomic
traits, Rasi and Abhisek were found to be phosphorus
deficiency tolerant.
Identification of QTLs associated with blast
resistance and development of QTLs -NILs
The cycle of backcrossing (BC 3
F 1
) for transfer of two
blast resistance genes, Pi2 and Pi9 in the background
of Vandana and BPT5204 was completed and confirmed
plants were selected for selfing. Simultaneously,
polymorphic flanking markers on either side of the gene
based SSR marker AP5930 were used for recombinant
selection for the both resistance genes, Pi2 and Pi9. Five
out of 30 hyper variable SSR markers on chromosome 6
were found polymorphic between the recurrent and
donor, and were used for background selection. Among
the five confirmed plants, four were similar to the recurrent
parent based on amplification pattern.
Identification of QTLs associated with
drought tolerance
Parental polymorphism survey with 206
microsatellite primers indicated that 81 were polymorphic
between Kalinga III and Salumpikit while 68 were
polymorphic between Kalinga III and Moroberekan.
Two hundred and thirty recombinant inbred lines of
the cross Kalinga III/ Salumpikit were evaluated for
reproductive stage drought tolerance under uplands
under rainout shelter. The parents showed statistically
significant differences at higher probability level for the
traits like grain yield, plant height, panicle length, filled
grains per panicle, per cent spikelet sterility and drought
score but not for biomass and canopy temperature
(Table 21). The phenotypic distributions in the RIL lines
for the traits mentioned did not show discrete classes
but approximately fitted a normal distribution, indicating
that all measured traits were quantitatively inherited
in nature. Transgressive segregation in both
directions was observed for most traits, indicating that
both parents transmitted favorable alleles for each trait.
Highly significant positive correlation (r=0.77) between
grain yield and filled grains per panicle was found,
indicating that genetic improvement in grain yield
Table 20. QTLs associated with root-knot nematode resistance in the rice variety Ramakrishna
Flanking Map position
QTLs Associated traits Chromosome marker (cM )
QMg1(t) Production og galls, eggs and eggs/gm root 1 RM495-RM428 13.7
QMg2(t) Production of galls 2 RM233A-RM14149 23.7
QMg3(t) Production of galls and eggs 3 RM231-RM7 21.0
52 CRRI ANNUAL REPORT 2011-12