| Summary: | 碩士 === 國立中興大學 === 植物病理學系所 === 96 === Transportation makes long - distance dispersal of plant - parasitic nematode possible. If plant - parasitic nematode adapted the new environment and built a large population it would make sever damage on the local agriculture. This thesis includes two experiments: Experiment A cultured the nematodes & host at different soil temperature for 45 days. In experiment B, after inoculate nematodes on the hosts, the plants were maintained in the GH for 15 days the proceeded to be treated & at different soil temperature. The experiments would clarify the impact of soil temperature on invading, growth and reproduce of three Meloidogyne species. Seven soil temperature treatment of M. incognita and M. javanica was studied between 10 ~ 40 ℃; M. hapla was treated with 10, 20, 30, 40 ℃. The results indicated, the optimum temperatures for invasion, growth, egg - hatching of M. incognita, M. javanica were 25, 30 ℃ respectively. The optimum temperature of M. hapla for invasion was 20 ℃, for growth was 30 ℃. M. hapla occurs more frequently in cooler climates, but they were also found in warmer climates. M. incognita, M. hapla at 40 ℃; M. javanica at 15、40 ℃ soil temperature developed slowly and did not have egg-masses. The results of staining experiment are that M. incognita, M. hapla could not grow at 10 ℃ soil temperature. The data of galling index in experiment B of M. incognita treated with 10, 15, 40 ℃; M. javanica 10, 35, 40 ℃; M. hapla 10, 30 ℃ soil temperature were significantly higher than those in experiment A. The phenomena indicated that soil temperature was one of the major factors to influence nematode invading. Exp. B nematodes also had significant higher growth rate than experiment A, indicated that nematodes were protected by host after invading into root, and the influence of soil temperature were less. The egg hatching rates of M. incognita in experiment A at 15, 35℃; M. javanica at 35℃ soil temperature were significantly higher than experiment B. The results implied, nematodes, which could invade at adverse temperature, might have tolerance traits thus the offspring had higher hatching rate. The data of J2 in the soil of three Meloidogyne sp. in Exp. A & B were not significantly different, this indicated soil temperature was not the major factor to influence on nematode life cycle and surviving ability. Two Meloidogyne species are mixed inoculated to study their competition in one host. The rate of invasion of M. incognita was higher than M. hapla and M. hapla was higher than M. javanica. The geography in Taiwan had low plain and high mountains provided great range of altitude & temperature. Plant parasitic nematodes from tropics or temperate zone had great risk to establish in our country, this study showed that 100% mortality with heat treatment in quarantine was necessary.
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