Responses of the Grain Yield and Agronomic Traits to the Planting Density of Japonica Type Rice (Oryza sativa L.) Cultivars Released from 1936 to 1993 in Taiwan
| Autor: | Fan, Hao-Chang, 范豪昌 |
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| Rok vydání: | 1999 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 87 The objectives of this study were to determine the effect of plant density on the yield and other agronomic traits in rice. 11 major rice cultivars that had been grown in Taiwan during the period of 1930-1990 were evaluated in the 1st crop of 1996 in Taipei at three plant densities (106,667, 160,000, 320,000 plants/ha with a randomized complete block design with 4 replications). The cultivars included in this study were (with year of releasing in brackets): TC65 (1936), CN8 (1941), HC56 (1953), CN242 (1956), TN5 (1965), KSS1 (1972), TN67 (1978), HC64 (1981), TN70 (1985), TK2 (1989), and TK9 (1993). The results were summarized as follows: 1. The performance of each agronomic trait of different cultivars was different under different planting densities. 2. The yield of TN67 was the highest among all cultivars, but it was found no significant difference between CN8 and TN67. In addition, TK9 and HC64 had the similar yield with TN67. 3. The more increase in planting density, the more yield could be obtained in each rice cultivar. However, yield increase was not obvious when planting density was more than 160,000 plants/ha. 4. Different cultivars and yield components varied in response to different planting densities. The more increase of planting density, the more decrease of spike numbers and spikelet numbers / spike. In the contrast, fertility and 1000-grain weight would increase under high planting density. 5. At high planting density, 70 % of yield was contributed by spike numbers and spikelet numbers / spike. At low planting density, fertility and 1000-grain weight influenced yields significantly. 6. New cultivars showed higher plant height, longer spike and stem length compared with old ones. 7. It was found there was existed highly correlation among yield / plant and biomass, panicle weight, straw weight, grain density and harvest index. Furthermore, biomass, straw weight and grain density increased with the era of breeding cultivar, but no similar tendency was found in panicle weight and harvest index. 8. The difference of the adjustment factor of the leaf area is similar in both in old and new cultivars. The average value was 0.6552 and the C.V. was 2.68 %. It suggested that the leaf shapes of the old and new cultivars were similar. 9.It showed that the spikelet numbers of mainstem was highly correlated with the numbers of first branch, second branch and grain density respectively in all cultivars. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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