Pathogenicity of the root-lesion nematode, Pratylenchus zeae, on rice genotypes under different hydro-ecologies in Tanzania

摘要

The root-lesion nematode, Pratylenchus zeae, is commonly found in upland rice fields. To measure the impact of the nematode on rice production, a screenhouse experiment was conducted using two farmer-adapted Oryza saliva cultivars, 'Supa' (`SurinamV-880') and 'SARO-5' ('TXD 306'), under flooded, upland and drought water regimes imposed at 7 days post-inoculation of mixed-stage nematodes (200. 500, 1000. 3000 and 10 000 plant(-1)). Growth and yield parameters were recorded, and the experiment was terminated after 5 months. 'Supa' was shown to be resistant to P. zeae, while 'SARO-5' was susceptible. Pratylenchus zeae reduced the growth and yield of both cultivars, though more for 'SiRO-5' than for 'Supa'. Yield decreased with increasing final nematode densities. Pratylenchus zeae reproduction was highest at 200 and 500 inoculum levels and under upland water conditions. The yield of 'SARO-5' was greater than that of 'Supa' under flooded conditions and with no or 200 and 500 nematode inoculum levels, but with high P. zeae inoculum `Supa' yield was better than 'SARO-5'.