Response to selection for high and low partial resistance to leaf blast in F2populations of three rice crosses

✍ Scribed by E. Roumen

• Publisher: Springer
• Year: 1996
• Tongue: English
• Weight: 420 KB
• Volume: 89
• Category: Article
• ISSN: 0014-2336
• DOI: 10.1007/bf00034612

✦ Synopsis

Divergent selection for higher and lower partial resistance to leaf blast was applied in F2 populations of crosses between the rice cultivars IR36, IR64 and C039 after exposure to a virulent isolate . IR36 and IR64 are partially resistant while C039 is highly susceptible. As selection criteria the number of sporulating lesions in leaves of the main culm or the lesion density in the topmost leaf relative to other F2 plants with the same stage of development were used. A highly significant and meaningful response to selection was obtained in most cases, but the heritability was low . Realized heritabilities varied from 0 .14 to 0 .25 depending on the cross and were similar for both selection criteria . Selection for improved partial resistance to leaf blast is possible as early as the F2 . The efficiency of selection is probably much higher if replicated tests could be made, and better results are therefore expected if selection among F3 lines is carried out . The results indicated that the relatively low infection efficiency in IR36 and IR64 is oligo-or polygenically controlled .