Assessment of quantitative resistance of rice cultivars toXanthomonas campestrispv.Oryzae:a comparison of inoculation methods

✍ Scribed by M. Koch; J. E. Parlevliet; T. W. Mew

• Book ID: 104618122
• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 514 KB
• Volume: 54
• Category: Article
• ISSN: 0014-2336
• DOI: 10.1007/bf00039604

✦ Synopsis

Lesion size and lesion number were measured on cultivars of rice inoculated by clipping or spraying with virulent isolates of Xanthomonas campestris pv. oryzae. Mean percentage diseased leaf area (% DLA) gave a similar ranking for the two inoculation methods but differences in lesion size among cultivars were much more evident after clip than after spray inoculation. Correlation between the methods was high (r = 0.82"*), but some cultivars responded differently with the two techniques. Cultivars which had low scores following spray inoculation showed low disease progress during the first nine weeks after transplanting into a screenhouse experiment. Assessment after clip inoculation measures resistance due to spread of bacteria within the leaf xylem system, an important component of quantitative resistance. Assessment after spray inoculation measures all resistance, including resistance to entrance of bacteria into the leaf. In order to select rice entries with improved quantitative resistance to X. c. oryzae based on both components, a screening based on lesion length after clip inoculation, followed by a test for lesion number after spray inoculation, is advised.