Response of upland rice cultivars to Meloidogyne species
1984; Volume: 7; Issue: 1 Linguagem: Inglês
ISSN
0183-9187
Autores Tópico(s)Soybean genetics and cultivation
ResumoSUMMARY Two screening tests and a field experiment were conducted with upland rice cultivars to identify sources of resistance to fWieloidogyne species and to evaluate their susceptibility with or without fertilization. In the first test, 41 upland rice cultivars (21 Oryza sativa and 20 O. glaberrinta) were screened. O. sativa cultivars were generally susceptible and O. glaberrirna cultivars resistant. Such widely used O. satioa cultivars as IRAT 13 and Iguape Cateto were susceptible whereas IS 335 and IS 358 were fairly resistant. In the second test, seventeen cultivars (eight improved and nine traditionnal non improved) were screened. Most irnproved cultivars (IRAT 109, IRAT 112, IRAT 106 and IRAT 133) were highly tolerant whereas most traditionnal cultivars were susceptible. A penetration and development study showed that cultivars rated susceptible were more favorable for larval penetration, development into adult females and reproduction than resistant or tolerant ones. In the field experiment Iguape Cateto gave up to 435% yield increase over the control with DBCP treatment and fertilizer application. In the presence of high M. javanica populations however no fertilizer response was observed. Symptoms of Meloidogyne attack include root galls (mostly terminal) consecutive with stopped longitudinal growth (characteristic roo ts), reduced stand, reduced tillering and panicle numbers as well as reduced general top growth with or without chlorosis and yield decrease. The use of characteristic roots as damage index is discussed. RESUME Rdponse de certains cultivars de riz pluvial a Meloidogyne spp.
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