Molecular characterization of bacterial leaf blight resistant

Jaccard’s similarity coefficient values ranged from 0.17

Conclusions

(between IET 20670 and GR 4) to 0.92 (between IET

A defence response against bacterial leaf blight disease

20670 and IET 21063) (Table 4.2.7). Among NILs of

was found mediated by resistance genes. Near isogenic

IR 64, IET 20667 (0.84), followed by IET 20669 (0.78)

lines of rice, used in this study, have been confirmed for

showed genetic proximity with its recurrent parent IR 64

the presence of bacterial leaf blight resistance genes ( xa5 ,

whereas, IET 20671 recorded genetic similarity to the

xa13, Xa4, Xa21 ), using molecular markers, therefore,

extent 0.69 with its recurrent parent Swarna. Among five

to bypass marker assisted selection and extensive field

NILs of Lalat, only one NIL IET 21065 showed moderate

screening, IET 21072 (near isogenic line of Tapaswini),

similarity (0.61). All the near isogenic lines of Tapaswini

IET 20668 (near isogenic line of IR 64), IRBB 60 and

exhibited low degree of similarity (< 0.5). Solitary NIL

some of the near isogenic lines among them, could be

of Samba Masuri (IET 19046) and Pusa Basmati-1 (IET

utilized as potential parents in hybridization programmes

18990) registered similarity coefficient of 0.62 and 0.7,

aimed at developing bacterial leaf blight resistant

respectively. Low to moderate values for similarity

varieties. The DNA markers, RAPD and SSR were also

coefficient were expected when either less recovery of

found useful for genetic diversity studies between near

recurrent parent or less number of molecular markers

isogenic lines and their recurrent parents.

used. The low similarity coefficient values such as, 0.17,

0.18, 0.20, 0.22 etc indicated that these are less similar

Acknowledgment

genotypes and will be useful for getting most diverse

The author gratefully acknowledges the Main Rice

recombinants in segregating generations, when they

Research

Station,

Anand

Agricultural

University,

are used as parents. Clustering pattern of dendrogram

Nawagam, Gujarat for proving the rice genotypes and

generated by pooled SSR data showed two major clusters

Department of Genetics and Plant Breeding, Anand

A and B. Cluster A included recurrent parents IR 64,

Agricultural University, Anand, Gujarat, for providing

Swarna, Tapaswini, Lalat and their respective NILs.

laboratory facilities.

Cluster B comprised Samba Masuri , Pusa Basmati-1 and

their respective NILs, IRBB 60 and susceptible check

References

cultivars. Cluster A was divided into two sub clusters A1

and A2. IR 64 and its NILs, Lalat and its NILs, Swarna

Babujee, L. and Gnanamickam, S. S. 2000. Molecular tools

for Characterization of rice blast pathogen (Magnaporthe

and its NILs and Tapaswini were in sub-cluster A1. NILs

grisea)

population

and

molecular

marker-assisted

of Tapaswini were in sub-cluster A2. Some SSR markers

breeding for disease resistance. Current Science 78 :

were found to be in linkage with BLB resistance gene

248–257.

along with some events of recombination. Since they

Bhat, K.V., 2002. Molecular data analysis. In: Proceedings of

were found to be linked to the resistance gene, they

the Short-Term Training Course on Molecular Marker

were found separated the near isogenic lines from their

Application in Plant Breeding, September 26–October 5,

recurrent parent. In this study, Tapaswini was included

ICAR, New Delhi.

in sub-cluster A1 which was separated from its NILs

Blair, M. W. and McCouch, S. R. 1997. Microsatellite and

included in sub-cluster A2. Sub-cluster A1 exhibited the

sequence-tagged site markers diagnostic for the rice

bacterial leaf blight resistance gene xa5 . Theorogical

maximum genetic proximity between NILs of IR 64,

Applied Genetics 95 : 174 - 184.

Lalat and Swarna to their respective recurrent parents.

Causse, M., Fulton, T. M., Cho, Y. G., Ahn, S. N., Wu, K., Xiao,

Cluster B was divided into two sub clusters B1 and B2.

J., Chunwongse, J., Yu, Z., Ronald, P. C., Harrington, S.

Sub-cluster B1 was formed by Samba Masuri, Pusa

B., Second, G. A., McCouch, S. R. and Tanksley, S. D.

Basmati-1 and their respective NILs, IRBB 60, GR 11,

1994. Saturated molecular map of the rice genome based

GR 4 and Jaya. Sub-cluster B2 was formed by GR 3

on an inter-specific backcross population. Genetics 138 :

and TN 1. Sub-cluster B1 showed the maximum genetic

1251 - 1274.

similarity between recurrent parents Samba Masuri and

Chu, Z., Binying, F., Yang, H., Xu, C., Li, Z., Sanchez, A., Park,

Pusa Basmati-1 to their respective NILs.

Y. J., Bennetzen, Q. Z. and Wang, S. 2006. Targetting

xa13 , a recessive gene for bacterial blight resistance in

437