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17 June 1990, Volume 4 Issue 2 Previous Issue    Next Issue
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研究报告
实验技术
研究报告
实验技术
研究简报


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研究报告

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Evaluation and Utilization of Usable and Unusable Heterosis in F1 Hybrids between Different Types of Indica and Japonica Rice Subspecies Yang Zhenyu,Zhang Zhongxu,Hua Zetian,Zhang Tielong,Gu Yiming 1990, 4(2): 49-55 .  Abstract ( )   PDF (489KB) ( )   Typical indica and japonica cultivars, cultivars with wide compatibility, indicaclinous and japonicaclinous strains and restoring lines were collected and crossed in this study. Twenty five F1 hybrids between indica and japonica subspecies were selected and divided into five groups. Using characters such as biomass yield, straw weight, plant height, days from seeding to heading, number of spikelets per panicle, number of grains per panicle and seed-setting rate as basic data, transgressive heterosis and competitive heterosis for each combination were determined. The results showed that there existed a correlation between straw weight and seed - setting rate in F1 hybrids between indica and japonica subspecies, and that the vigor contained two parts: usable and unusable. The heterosis in a typical indica-japonica F1 hybrid was hard to use. However, pairing a wide compatibility line With an indicaclinous or a japonicaclinous restoring line or their derivatives, or pairing a wide compatibility line with another wide compatibility line, would allow partial use of the heterosis in hybrids between the two subspecies, and therefore should be emphoyed as an important breeding strategy in better use of the heterosis at present.

实验技术

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Modified Single Grain Analysis for Gel Consistency Tang Shengxiang,G S Khush,B O Juliano 1990, 4(2): 55-55 .  Abstract ( )   PDF (71KB) ( )   Rice; Gel consistency; method

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Effect of Irrigation Modes on the Senescence and Physiological Activity in Hybrid Rice after Heading Ma Yuefang,Lu Dingzhi 1990, 4(2): 56-62 .  Abstract ( )   PDF (548KB) ( )   The effect of irrigation modes on the senescence of hybrid rice and some physiological activity was studied in the experiment. The results showed that irrigation modes affected obviously the senescence of hybrid rice. By cutting off the water supply at different stages after flowering, plant was subjected to water stress, and the decrease rate of the physiological activity speeded up, then the rate for the accumulation of dry weight in grain slowed down and seed setting percentage reduced, as a result, the output reduced. The earlier stare the water supply was cut off at, the more serious the yield reduced. However, intermittent irrigation, because of delaying the senescence of root, increasing photosynthetic rate, prolonging the duration of the accumulation of dry weight in grain, enhancing seed setting, and raising efficiency of increase production, consequently, the yield respectively increased by 7.4% and 17.7-28.3% compared with long term irrigation and cutting off the water supply earlier than expected. It is possible that irrigation modes control the senescence of the aerial parts by means of promoting the synthesis of some amino acids and restraining the synthesis of other amino acids in roots.

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Evaluation of Hybrid Rice Combinations for Resistance to Sitotroga cerealella Olivier in Stored Grain Wu Rongzong 1990, 4(2): 63-68 .  Abstract ( )   PDF (255KB) ( )   This paper deals with the resistance of hybrid rice to Angoumois grain moth (AGM), Sitotroga cerealella. Three tested treatments, 3 pairs of adults, 100 or 200 eggs of AGM which infested separately 5g sample of seeds with 4 replications were used in experiment. The moisture content of seeds was adjusted to 13%. After infestation, the samples were stored in constant environment at 27℃ and 75% R. H., and observed on different resistant parameters, including the percentage of aduIts emerged, development period, susceptibility index and percentage of grain loss. The results showed that the resistances of each variety were on the same level in three treatments tested. Highly significant positive correlation (P<0.001) existed between grain loss and percentage of adults emerged, and also existed between grain loss and susceptibility index. A negative correlation between grain loss and development period was distinctly significant (P<0.01). No correlation belween gram loss and adult weight, or between grain loss and sex ratio was observed. Since the treatment of infestation with 100 eggs may save the amount of seeds and insects tested, and also can be used to exactly evaluate the resistance in different seasons, thus this treatment has been applied to screen the resistance of hybrid rice. Of the 38 hyrid rice combinations tested, one exhibited resistant and eight moderately resistant. The results indicated the susceptibility of hybrid rice was generally higher than the regular rice variety.

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Studies on the Eco-adaptability of Lowland and Upland Rice Varieties to Paddy and Upland:Ⅱ. Carbohydrate Nitrogen Metabolism Zheng Piyao,Yang Kongping,Wang Jingwu,Zhou Dianxi 1990, 4(2): 69-74 .  Abstract ( )   PDF (372KB) ( )   The eco-adaptability of rice (Oryza saliva L. ) to paddy and upland were studied with three varieties of lowland and upland rice under paddy and upland in 1985—1986. On upland, the rice plants expressed high concentration in carbohydr ate and nitrogen, high ratio in soluble sugars and low C/N ratio. The upland rice variety consisted of much more soluble sugars than that of lowland rice varieties. It was a eco-adaptability of rice plants to upland for increasing storage, especially in soluble sugars. Those rice varieties, which was with high ratio in soluble sugars, might be adapted to upland.

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Genetic Analysis of Cold Tolerance at the Seedling Stage of Early Rice (O. sativa L. subsp. indica) Xiong Zhenmin,Min Shaokai,Wang Guoliang,Cheng Shihua,Cao Liyong 1990, 4(2): 75-78 .  Abstract ( )   PDF (268KB) ( )   Inheritance of seedling cold tolerance was examined in three crosses between tolerant and sensitive parents by growing seedlings in the phytotrom after keeping them at 6℃ for 48 hours. Cold tolerance was measured by leaf yellowing after the treatment of low temperature then recovery at 30℃/25℃ for 24 hours and by plant dying recovery for 48 hours are both govered by a single dominant gene. A single dominant gene also controls the cold tolerance as measured by specific conductivity, which was shown higher in sensitive parent than in tolerant one.

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Studies on Keeping Freshness of Rice Germ during Storage Hu Jun,Chen Zhongming 1990, 4(2): 79-83 .  Abstract ( )   PDF (225KB) ( )   It was studied that retarded the rancidity of rice germ during storage with the different packages, packaging vacuity, temperature and radiation dosage. The result showed that were all advantageous to retard the rancidity of rice germ during storage at room temperature or low temperature with the Polyester(PET)/Polyethylene (PE) vacuum packaging or with radiation of the low density polyethylene packaging (LDPE).

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Studies on the Residues and Degradation Behavior of Herbicide Bentazon in Rice Liang Tianxi,Lou Xiaohua 1990, 4(2): 84-88 .  Abstract ( )   PDF (290KB) ( )   An analytical method and the degradation behavior in the ecological environment of paddy field for the residues of Bentazon (48% aqueous formulationt is reported. The degradation half lives of bentazon in rice grain, soil and water were calculated. If the herbicide was sprayed once during the three-leaf stage of herbs 60 days before harvest with the application volumn of 300ml/mu deluted to 50 liters by water, the final residues of bentazon and its metabolites in rice grain would be bellow the minimun detected limits (0.02 mg/kg).

实验技术

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Alkaline Digestion and Oxidation for the Speed Determination of the Silica in Rice Hull Zhu Zhiwei,Lin Ronghui 1990, 4(2): 89-91 .  Abstract ( )   PDF (212KB) ( )

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Study on the Relationship between Cytoplasmic Male-sterility and Cyanide-resistant Respiration of Tissues in Rice (Oryza sativa) Chen Xianfeng,Liang Chengye 1990, 4(2): 92-94 .  Abstract ( )   PDF (159KB) ( )

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Preliminary Studies on Induced Resistance to Rice Plants by Non-pathogenic and Mild Pathogenic Isolates of Pyricularia oryzae Cav. Shen Ying,Huang Danian,Fan Zaifeng,Qiu Dewen,Wang Jinxia,Zou Qin 1990, 4(2): 95-96 .  Abstract ( )   PDF (152KB) ( )