Pathein Maubin Dedaye Bogalay Pyapon
UNION OF MYANMAR
Figure 1. Collection sites (townships) of test isolates of X. oryzae pv. oryzae
Plate 1. Measuring infected and total leaf areas of inoculated leaves by computer-assisted image analysis method
A. Inoculated leaves, on which % leaf area infected is to be measured
B. Opening the file; image of the leaves appeared on the image window of Sigma Scan Pro 5.0 C. Duplication of the image of leaves to be measured
D. Overlaying with red colour on the infected portion of the duplicated image of leaves using fill mode; colour threshold method was applied to measure the infected area
E. Measuring the infected leaf area; the area was shown on the data work sheet
F. Measuring the total leaf area; the original image of the leaves was duplicated again, the entire portion of the duplicated image of the leaves was defined using fill mode, and total leaf area was shown on another data work sheet
A B
C D
E F
0 2 4 6 8 10
I-04172 I-0505 I-0530 I-04107
Isolates of Xanthomonas oryzae pv. oryzae
Disease score
IRBB 3 IRBB 7 IRBB 13
Figure 2. Virulence of four isolates of Xanthomonas oryzae pv. oryzae on three near isogenic lines
Evaluation of Myanmar Rice Germplasms for Resistance to Different Races of Xanthomonas oryzae pv. oryzae
Indigenous rice germplasms of Myanmar were evaluated for resistance to four Myanmar races of X. oryzae pv. oryzae. On the basis of reaction patterns to representative isolates of four races, 134 rice germplasms were categorized into four varietal groups, Group A, B, C and D.
Seventy-eight rice germplasms included in Group A were susceptible to all of the representative isolates of four races. In Group B, there were 50 rice germplasms and they were resistant to Race 11, but susceptible to other three races. Only 4 and 2 rice germplasms belonged to Group C and D, respectively. Four rice germplasms of Group C, Khae Saba, Van Lai Phal, Ant Baw and Baw Gyi, were resistant to two races, Race 7 and 11. Mya Wut Yi and Taylay, which belonged to Group D, were resistant to three races, Race 7, 11 and 17 (Table 6 and 7).
Isolates of Xanthomonas oryzae pv. oryzae
Plate 2. Disease reaction of IRBB 21 and TN 1 to fourisolates of Xanthomonas oryzae pv. oryzae
Plate 3. Disease reaction of three near-isogenic lines, IRBB 3, IRBB 7 and IRBB 13 to four isolates of Xanthomonas oryzae pv. oryzae
04172 0505 0530 04107 IRBB 21
04172 0505 0530 04107 TN 1
04172 0505 0530 04107 04172 0505 0530 04107 04172 0505 0530 04107
IRBB 3 IRBB 7 IRBB 13
Table 6. Grouping of 134 Myanmar rice germplasm on the basic of reaction patterns to four isolates* of Xanthomonas oryzae pv. oryzae
Group Varieties
A Khao Kain, Magauk, Saba Ni, Khao Hlaing, Moe Thay, Kyaw Par Lae, Kha Yan Gyar, Chin Pa Chee, Khao Mon Moe Nae, Khao Mon Han Young,
Lin Ban Chaw,Khao La Shae, Khao Pha Yaung, Bu Do Ya, Saba Khar, Khao Pae Law, Khao Maw Kyan, Ekare, Ekarin Kwa, Shwe Pyi Aye, Bu Har, Baria, Rel Beng, Dug Thin, Kalagyi, Kyaw Galay, Kari Let Yone, Lone
Phyu, Yay Thu Ma, Shan Nyein, Kyun Shwe War, Nga Kauk Che, Sar Pa Si Chay, Nga Kyein Thee, Sa O Me, Ohn Ni Ma, Ya Khine Ma, Khao Saw, Khao Man Mu, Khao Kan, Let The Zaung, Pale Pyu, In Gyin Su, Kauk Latt Phyu, Shan Ma Lay, Pa Dee Pu, Pa Che Mwe Swe, A Pyo Daw Gyi, Kyauk Htu, Phwe Htaung Ni, Ye Tha, Sabani Hmwe, Ah Nauk Chaung, Yatha Lay Long Thwe, Nga Kywe Taung Pyan, Khun Na Ya Thee Dat, Nga Pya Yin, Bu Thout, San Gyi, Pin Shwe War, Kalar Htun, Sa Sar, Shwe Phyu, Thone Hnan Latt, Tha Htay
Gyi, Ywet Thay, Mwe Swe, Okshit, Naung Aine, Taung Hteik Pan, Kauk Thwe Phyu, Thet Nu Bay Kyar, Nga Kyee Du Me, Let Yone, Kauk Thwe, Let Yone Gyi, Kywe Chae Manaing and Nga Yar Nga Se
B Naung Tu, Let The Nu, Khao Lar Say, Nga Yar Gyaw, Kauk Kyi Saw, Shwe Pu, Yay Thu Ma, Epa Tine, Dawe Sein, Kala Lay, Ekare Phyu, Naga Yar, Mya Sein, Bahat Ni, Gauk Ya, Ah Nauk Thama, Khao San Haung, Khao Man Mon Tine, Khao Kyaine, Khao Kyauk Oun, Khao Mwe Naung, Khao Note Tit, Takade, Tay Lay, Shwe Bo Khun Ni, Ya Thae, Wun Htauk, Nga Sein Du Me, Shwe Chay Gyin, Paw La Khe, Thone Poke Ta Pote, Nga Kywe Phyu, Shwe Dinga, Aung Lan Daw, Pyi Daw Aye, Hnan War, Wa Ti Tun, Du Wa Pho, Ban Gauk, Man Nga Sein, Mee Kauk, Shwe Kyi Dauk, Kauk Sann, Shwe Kyi Nyo, Ngar Yar Kyaw, Baw Kyan, Ma Po Lay, Maung Nyo Sann, Balakyar and Phya Pon Thee Dat
C Van Lai Phai, Ant Baw, Khae Saba and Baw Gyi
D Mya Wut Yi and Talay
*: Representative isolates of 4 races, 04172, 0505, 0530, and 04107, i.e., races 11, 17, 7, and 14, respectively
Table 7. Disease reactionx of four groups of rice germplasms to four isolates of Xanthomonas oryzae pv. oryzae
Isolatesy Varietal
group
No. of germplasms belong to
each group 04172 0505 0530 04107
A 78 S S S S
B 50 R S S S
C 4 R S R S
D 2 R R R S
x R = resistant, 0 to 12% leaf area infected S = susceptible, 13 to 100% leaf area infected
y Representative isolates of 4 races, 04172, 0505, 0530 and 04107, i.e., races 11, 17, 7, and 14, respectively
In order to develop bacterial blight resistant varieties, selection of appropriate donor parents which show broad spectrum of resistance is important for the breeding program. Thus, evaluation of introduced and indigenous rice germplasms for bacterial blight resistance is one of the primary tasks for rice genetic resources management and utilization. In the present study, 134 indigenous rice germplasms of Myanmar were evaluated for resistance to four Myanmar races of X. oryzae pv. oryzae. It was observed that, majority of the indigenous rice germplasms, i.e. 78 germplasms of Group A, were susceptible to four Myanmar races. On the other hand, 50 rice germplasms included in Group B were resistant to Race 11. This race was one of the three predominant races detected in this study and distributed in three major rice growing divisions, Ayeyarwady, Bago, and Mandalay Divisions. Therefore, these rice germplasms could be used as resistant donors in varietal improvement program for those divisions.
The discovery of pathogenic specialization led to the incorporation of different resistance genes into improved cultivars. Thus, modern breeding program paid an attention to develop rice varieties which are resistant to multiple races of X. oryzae pv. oryzae. In the present study, Khae Saba, Van Lai Phal, Ant Baw and Baw Gyi were resistant to Race 7 and 11, and Mya Wut Yi and Taylay were resistant to Race 7, 11 and 17. These three races were predominant races detected in four major rice growing divisions of Myanmar. It indicated that these six indigenous rice germplasms were potential donors for multiple race resistance in breeding program for bacterial blight in Myanmar.
References
1. CARI. 2001. Catalogue 2001, Germplasm Accessions, August 2001, Seed Bank, Central Agriculture Research Institute, Yezin, Myanmar.
2. Ezuka, A. and H. Kaku. 2000. A historical review of bacterial blight of rice. Bull. National Institute of Agro-biological Resources, Japan.
3. IRRI. 1988. Standard Evaluation System for Rice. 3rd Ed. International Rice Testing Program, IRRI. Los Banos, Laguna, Philippines.
4. Nakagahra, M. 1978. The differentiation, classification and center of genetic diversity of cultivated rice (Oryza sativa L.) by isozyme analysis, Trop. Agr. Res. Ser. (TARC) 11: 77-82.
5. Nakagahra, M. 1987. Rice and its home. Kokon Books, Tokyo, Japan pp. 111-148.
6. Noda, T., T. Yamamoto and O. Horino. 1996. Geographical distribution of pathogenic races of Xanthomonas oryzae pv. oryzae in Japan in 1991 and 1993. Ann. Phtopathol.
Soc. Jpn. 62: 549-553.
7. Ou, S.H. 1985. Rice diseases. Second Edition. Commonwealth Mycological Institute, Kew, England.
8. Roger, P.A., K.L. Heong and P.S. Teng. 1991. Biodiversity and sustainability of wetland rice production: Role and potential of microorganisms and invertebrates. pp. 117-136. In:
The biodiversity of microorganisms: its role in sustainable agriculture. Hawksworth, D.L., editor. CAB International, UK.
9. Zadoks, J.C. and R.D. Schein. 1979. Epidemiology and plant disease management.
Oxford University Press. New York. 427 p.