| Summary: | 碩士 === 國立屏東科技大學 === 熱帶農業研究所 === 88 === A combination of nitrogen (N) and potassium (K) fertilizer were used on three varieties of rice; a susceptible variety, Taichung Native 1, and two resistant varieties, Chia Non Shi 862118 and Chianung Shi 862048, which were then exposed to the brown plant hopper, Nilaparvata lugens (Stal).Three tests were carried out to determine the response of N. lugens to rice in terms of their preference, antibiosis, and tolerance under green house conditions.
There was significant difference between the susceptible and resistant rice varieties in preference, antibiosis, and tolerance of N. lugens, however, no significance was detected in N. lugens response to different cultivars of rice under N and K fertilizer treatment. In the preference test N. lugens population on susceptible varieties started to increase 24 hrs after exposure but reduced on the resistant varieties.In the antibiosis or survival test there was significant difference between resistant and susceptible varieties in the duration growth and the percentage survival of N. lugens nymphs. The percentage survival of N. lugens on resistant varieties was 35% - 55%, as opposed to the susceptible variety at 73-88%. The duration growth for N. lugens on the resistant varieties was 17.2- 18 days, as opposed to the susceptible variety in 13 days. The number of macropterous N. lugens appeared to be higher on the resistant varieties than on the susceptible varieties even though it was not statistically significant. There was a significant difference in the rate of damage between the susceptible and resistant varieties. This study indicates that application of fertilizer did not alter the susceptibility of rice varieties. However, increasing the amount of nitrogen slightly increased the population of N. lugens and also slightly reduced the duration of growth of N. lugens from nymphs to adults on susceptible varieties. It also indicates that the varietal resistance to insect attack was a complex adaptive biochemical interaction between the resistant and the insect. The interaction can be expressed by non-prefernce, antibiosis or tolerance of an insect therefore the effects of the plant resistance to an insect are persistently cumulative, causing an overall reduction in the insect population on resistant varieties.
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