Studies on the Nature of Resistance of Rice Plant to Bacterial Leaf Blight Caused by Xanthomonas oryzae (Uyeda et. Ishiyama) Dowson

벼 흰빛잎마름병에 대한 수도 품종의 저항성에 관한 연구

The study has been carried to investigate the nature of resistance in rice varieties against bacterial leaf blight caused by Xanthomonas oryzae (Uyeda et. Ishiyama) Dowson. In this study, differences on several morphological histological and bacterial growth in rice leaf extract from different varieties were examined. Shirogane and Norm 6 as resistant varieties, Paldal as moderately resistant, and Jinheung, Kimmaze and Suwon 213 as susceptible varieties were used throughout the experiment. 1. Susceptible varieties Jinheung, Kimmaze have more hydathods in flag leaf than resistant varieties but there were no difference between resistant varieties and moderatly resistant varieties. 2. Average length of xylem vessel elements were 50r longer in leaf veins of susceptible varieties Jinheung, Kimnaze and Suwon 213 than those of resistant varieties, but there were no difference among Paldal, Norm 6 and Shirogane. 3. Kimmaze and Suwon 213 have larger diameter of xylem vessel elements than those of other varieties examined. However, it did not differ significantly between resistant varieries and susceptible varieties statistically. 4. Jinheung and Kimmaze have more secondary xylem vessels in root of 6-7th leaf stage than those of Shirogane and Norm 6. Suwon 213, however, showed least number of secondary xylem vessels exceptionally. 5. Leaf extract from resistnat variety Shirogane, suppressed bacterial growth significantly when compared with those from other varieties. 6. Bacterial growth in autoclaved leaf extract from resistant varieties and susceptible varieties did not show any noticeable difference. In general, fresh extract maintained more bacteria than in autoclaved extract after 48 hours of incubation period.

1. 지엽에 있어서 배수선의 또는 감수성인 품종이 저항성인 품종보다 평균 6개 이상 많았으며 중간성과 저항성 품종간에는 차이가 없었다. 2. 엽맥의 도관절의 길이는 감수성인 진흥, 김마제 수원 213호 등이 저항성 품종보다 길었으며 팔달 시로 가네 농릴 6호 등은 차이가 없었다. 3. 도관의 직경은 김마제쓱 수원 213호가 다른 4 품종에 비하여 길었으나 저항성품종과 감수성 품종간에는 유의차가 없었다. 4. 6-7엽기에 이른 뿌리의 후생도관은 진흥 김마제가 시로가에, 농릴 6호 보다 휠씬 많았으나 수원 213호는 예외적으로 후생도관수가 가장 적었다. 5. 저항성인 시로가네의 즙액에서는 감수성품종에 비하여 세균의 증식이 현저하게 억제 되였고 다른 품종들 간에는 차이가 없었다. 6. 열처리된 즙액에서는 저항성 품종이나 감수성품종에 관계없이 세균증식이 비슷하였고 전체적으로 신선한 즙액에서 보다 세균수가 훨씬 적었다.