Economic Characters of Thirty-three Chinese Rice Cultivars in Angola

[Objective] The aim was to research economic characters of thirty-three Chinese rice cultivars in Angola.[Method] In the research,twenty-eight hybrid mid-indica rice cultivars and five conventional Japonica rice cultivars were classified into three groups and then grown in Luanda to analyze adaptability,fertility and major economic characters of the rice in rainy season.[Result] The research showed that of twenty-eight hybrid mid-indica rice cultivars,ten cultivars were of better adaptability and fertility,which are suitable to be grown in Luanda in Angola;productive ear number,total grain per ear,thousand-seed weight and ratio of grain to straw of the rice cultivars performed normally,but the whole developmental period shortened and seedling setting rate improved significantly.In addition,hybrid indica Teyou 721,Quanxiangyou 512,II you 128 and 102S/4HZ021 were of fertility potential at 11.5 t/hm2,which were all proved excellent in related characters in rainy season in Luanda of Angola.For conventional mid-season rice indica cultivars,Wandao 51 and Huanghuazhan were of better adaptability and fertility.In contrast,5 Japonica rice cultivars were of poor adaptability.[Conclusion] The research provided technical references for Chinese rice growing in Angola.

Simulation of Soil Organic Carbon Dynamics in Chinese Rice Paddies from 1980 to 2000

Changes in soil organic carbon （SOC） of rice paddies in China were simulated from 1980 to 2000 by linking a coupled bio-physical model to GIS database. The coupled model consists of two sub-models including Crop-C for simulating net primary productivity and hence residue retention and Soil-C for computing the turnover rates of SOC. The GIS database included parameters of climate, soils and agricultural activities with the resolution of 10 km × 10 km. Model simulation indicated that Chinese rice paddies covering 22.6 Mha sequestrated a considerable amount of C, about 0.15 ± 0.07 Pg C from 1980 to 2000. Annual sequestration rate increased sharply from -180 ± 45 kg C ha^-1 year^-1 in 1980 to 440 ± 170 kg C ha^-1 year^-1 in 1989. Thereafter, a steaziy sequestration rate of 460 ± 170 kg C ha^-1 year^-1 occurred till 1994 and declined since then. Approximately 84% of the Chinese rice paddies sequestrated carbon, while 15% lost carbon and 1% kept balance over the 20 years. Great SOC sequestration occurred in eastern, southern and central China, while a slight decline of SOC existed in some regions of northeastern and southwestern China.

Phthalates in Commercial Chinese Rice Wines: Concentrations and the Cumulative Risk Assessment to Adult Males in Shanghai

The concentrations of 16 phthalates in 164 commercial Chinese rice wines （CRW） were detected by GC-MS, and consumption data on CRW in different packaging types was investigated from 634 adult males in Shanghai using a food frequency questionnaire. Based on the prinq：iples of probabilistic modelling and cumulative risk assessment, the exposure and health risk of phthalates from CRW to adult males in Shanghai was evaluated. DMP, DEP, DIBP, DnBP, BBP, and DEHP were detected in the samples, thE： range of detection frequency of individual phthalates varied from 6.10% for BBP to 15.24% for DIBP, and the detected concentrations were 51.06-200.34 ng/mL. All the respondents consumed CRW, 90.69% of them consumed CRW 0.01-49.9 mL/d, the minimum value of the average daily intake of CRW was 6.25 mL/d, the median was 13.72 mL/d and the maximum was 300 mL/d. The median exposure level of the 6 detected Phthalates to adult males in Shanghai were 6.58-7.10 ng/（d.kg）, and the maximum exposure level were 137.38-540.47 ng/（d.kg）. The cumulative exposure health risk index （HI） based on the median and maximum exposure level of the 6 Phthalates （DMP, I~）EP, DIBP, DnBP, BBP, and DEHP） were 0.001147 ancl 0.063396, both were far less than 1. In conclusion, CRW were generally consumed by the adult males in Shanghai.

CH_4 EMISSION FROM A CHINESE RICE PADDY FIELD

CH_4 emission rates have been measured continuously for the early rice of 1988 and late rices of 1987 and 1988 during entire growing seasons in a rice paddy field in Hangzhou,Zhejiang Province,China,by using an automatic sampling and analyzing system.During most parts of the seasons CH_4 emission rates showed strong diurnal variations.Bi-mode patterns with the highest value in the afternoon and a second peak at mid-night were generally found for the early rice,while the highest values were almost always found in the night for the late rice.Bi-mode patterns with a second peak in the afternoon were also found during the reproductive phase of the late rice plants.These diurnal variations may be explained by the diurnal variations of the soil temperature and the activity of rice plants.Strong seasonal variations with one peak in the tillering stage and two during the reproductive phase of rice plants were observed for all the three growing seasons.The seasonal variations may be explained by the activity of rice plants,availability of organic substrates in the soil,and the activity of soil bacteria related to soil temperatures,Fertilization did not show significant effects on the total seasonal CH_4 emissions but slightly changed the pattern of the seasonal variations of the CH_4 emission rates.Averaged over the measuring periods and 8 spots,CH_4 emission rates of 7.8 mg m^(-2) h^(-1) for the early rice and 28.6 mg m^(-2) h^(-1) for the late rice were obtained. Based on these measured data,the total global emission of CH_4 from rice paddies is estimated to be about 90 Tg/yr ranging from 70 to 110,accounting for 20% of the total source of CH_4.

Optimization of rice wine fermentation process based on the simultaneous saccharification and fermentation kinetic model

Chinese rice wine making is a typical simultaneous saccharification and fermentation （SSF） process. During the fermentation process, temperature is one of the key parameters which decide the quality of Chinese rice wine. To optimize the SSF process for Chinese rice wine brewing, the effects of temperature on the kinetic parameters of yeast growth and ethanol production at various temperatures were determined in batch cultures using a mathematical model. The kinetic parameters as a function of temperature were evaluated using the software Origin8.0. Combing these functions with the mathematical model, an appropriate form of the model equations for the SSF considering the effects of temperature were developed. The kinetic parameters were found to fit the experimental data satisfactorily with the developed temperature-dependent model. The temperature profile for maximizing the ethanol production for rice wine fermentation was determined by genetic algorithm. The optimum temperature profile began at a low temperature of 26℃ up to 30 h. The operating temperature increased rapidly to 31.9 ℃, and then decreased slowly to 18℃ at 65 h. Thereafter, the temperature was maintained at 18 ℃ until the end of fermentation. A maximum ethanol production of 89.3 g.L 1 was attained. Conceivably, our model would facilitate the improvement of Chinese rice wine production at the industrial scale.

Characterization of Interspecific Hybrids Between Oryza sativa L, and Three Wild Rice Species of China by Genomic In Situ Hybridization

In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice （Oryza sativa L.）. In the present study, hybrids between O. sativa （AA genome） and three Chinese wild rices, namely O. rufipogon （AA genome）, O. officinalis （CC genome）, and O. meyeriana （GG genome）, were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid, the other F1 hybrids were completely sterile. Genomic in situ hybridization （GISH） was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4＇,6＇-Diamidino- 2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatin compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.