| Summary: | 碩士 === 國立臺灣大學 === 農藝學研究所 === 88 === The aims of this study were to compare the yield and other agronomic traits of major Japonica rice cultivars released from 1936 to 1993 under different levels of nitrogen fertilizers and temperature treatments.
Twelve major cultivars ( TC65(1936), CN8(1941), HC56(1953), CN242(1956), TN5(1965), KSS1(1972), TN67(1978), HC64(1981), TN70(1985), TK2(1989), TK8(1992) and TK9(1993) ) were grown in 1/2000are Wagner plastic pots of National Taiwan University Agriculture Experimental Farm, Taipei, in 2nd Crop of 1996 and 1st crop of 1997 respectively. Nitrogen fertilizer was applied in the 2nd crop and 1st crop with 80,130,180 kg /ha and 80,160,240 kg/ha. Calcium superphosphate and potassium chloride were applied in both of these experiments were 90Kg and 60Kg respectively. On the other hand, 9 Japonica rice cultivars ( TC65, CN8, TN5, TN67, HC64, TN70, TK2, TK8 and TK9 ) were also grown in 1/5000a Wagner plastic pots in the Phytotron under four different temperature conditions ( 20/15℃, 25/20℃, 30/25℃ and 35/30℃ ) in the phytotron of National Taiwan University in the 1st crop of 1997. 160 kg /ha ammonium sulfate, 90kg/ha calcium superphosphate and 60 kg /ha potassium Chloride were applied in this experiment. The results were summarized as follows:
1.Old cultivars TC65, CN8 and HC56 produced the highest yield under different levels of nitrogen fertilizer treatments in both seasons. Recent cultivars TN67, TN70 and TK9 produced the highest yield especially at 1st crop experiment, the results indicated that although rice quality was one of the traits concerned in the breeding programs, the yield was still the most important trait.
2.TN65 produced the highest panicle number per hill under both fertilizer and temperature treatment. TN65, CN8, HC56, TN5 and KSS1 produced higher yield than that of other cultivars in the fertilizer treatment.
3.TN67 produced the highest spikekets per panicle. During recent 10 years, it showed a tendency of increasing the more number of spikekets/panicle and fertility and shortening the plant height according to the increase of years in all TK cultivars.
4.No. of tillers per hill for recent cultivars TK2, TK8 and TK9 were lower than that of old cultivars TC65 and CN8, but the effective No. of tillers and 1st branch number were higher.
5.In 2nd crop, the total plant weight of recent cultivars TN67, HC64, TN70 and TK9 were higher than that of old cultivars TC65, CN8, HC56 and TN5, but the harvest index was lower.
6.Old cultivars TC65 and CN8 headed more early than other cultivars, it suggested that they were adapted to be grown at 2nd crop of Northern Taiwan.
7.Under optimum temperature treatment, there was no significant difference on yield among all cultivars.
8.Old cultivars TC65 and CN8 produced more stable yield under different temperature treatments.
9.Under 20/15℃ treatment no yield was found in all cultivars because the delay of heading and the sterility of spikelets.
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