Chen Wen-fu

Effects of Weedy Rice on Yield and Quality and Micro-Ecological Environment in Cultivated Japonica Rice Population

Weedy rice WR04-12 and cultivated rice Liaojing 294 were used in field experiment.The results showed that the significant decrease of yield in Liaojing 294 was induced by increasing weedy rice density.The decrease of number of rice panicles and spikelets per panicle,was one of the main reasons causing yield loss of cultivated rice.Milling quality,nutrient quality,and taste quality of cultivated rice decreased with the increasing of weedy rice density,while apparent quality did not show the same trend.The daily minimum temperature and minimum humidity increased in some degree,but the maximum temperature,daily temperature difference,maximum humidity,and daily humidity difference decreased in the cultivated rice population with increasing weedy rice density.The illuminance,at 60 and 90 cm from ground of cultivated rice seems to be decreased with the increase of weedy rice density and that at 30 cm was not influenced by this parameter.As a whole,the weedy rice was a negative effect on micro-ecological environment of cultivated rice population which is the indirect reason of decreasing yield and quality.

Application Effect of Biochar on Rice

New technology of dry distillation under hypoxia condition was used for made biochar (biomass-derived black carbon).The effects of biochar application on rice were studied by pot experiment. Before rice transplant, soil were treated with three different weight levels of biochar and no biochar as control(CK).The results show that biochar amendments in rice soil could boost height of rice, and also increased the dry matter accumulation of leaf, stem and root at various growth stage. The rice net photosynthetic rates of biochar treatments were higher than control. Transpiration rate of biochar treatment was increased at the tillering stage and filling stage, declined at the jointing stage and heading stage as well. Rice yield per hill of biochar treatments were higher than control for the main reason of the panicles per hill and spikelets per panicle increased. The rice yield of C2 (20g·kg−1 biochar amendment) was the highest which significant difference compared with other treatments. Rice milling and appearance quality of biochar treatments were better than control with brown rice rate, milled rice rate and head rice rate were increased while the chalky grain rate and chalkiness were decreased. Rice protein and fatty acid content of biochar treatments were decreased, but the rice cooking quality was significantly increased.

Research progess of rice erect panicle gene DEP1

With the development of molecular biology, several genes relative to grain yield traits have been cloned in rice. Among these genes, only DEP1 (dense and erect panicle 1) has been widely used in rice breeding. The objective of this review is to summarize the previous research for DEP1 and look into its development prospect. DEP1 gene codes a heterotrimeric G protein γ subunit. The loss of its cysteine-rich domain increases signal transmission of G protein, which may result in stronger meristem activity, increased number of branches and grains per panicle, higher nitrogen use efficiency, and consequent increase in grain yield. Moreover, the erect panicle architectures improve the canopy structure and lodging resistance, which lead to higher material production capacity in population. Therefore, the plant type improvement on the basis of the erect panicle gene DEP1 will bring the third breakthrough of grain yield in rice breeding history after the semi-dwarf breeding and the application of heterosis in hybrid rice.

Effects of Phosphate Fertilizer on Cold Tolerance and Its Related Physiological Parameters in Rice Under Low Temperature Stress

The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings (chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81) under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.

Identification and Analysis of Physiological Races of Magnaporthe oryzae in Heilongjiang Province

Abstract A totatl of 116 isolates of rice blast fungus, Magnaporthe oryzae, were collected from 45 samples in different counties of Heilongjiang Province, and 20 Chinese physiological races belonging to seven groups were identified by using seven standard Chinese rice blast identifying varieties. Results showed that the dominant groups could be ranked as ZA, ZD, and ZB, with the occurrence frequencies of 47.41%, 22.41% and 15.52%, respectively. The race ZA 49 was the dominant race with the occurrence frequency of 26.72%. The occurrence frequencies of the races ZD 5 and ZD 1 were 10.34% and 8.62%, respectively. The rising occurrence frequencies of these three dominant species were the most important reasons that causing Kongyu-131 more sensitive to rice blast. The results of virulence frequency indicated that the race harboring Pi-k, Pi-i, Pi-a gene were more susceptible to rice blast in Heilongjiang Province, and they should not be large-scale cultivated.

Roles of biomass-derived black carbon in soil and environment ecosystem: A review

As the global warming intensifying, Climate change has become an important environmental problem which has caused great concern around the world. Reducing the effects of greenhouse gases to the climate and ecosystem and stocking more carbon sequestration are the solved critical problems which government and scientist around world must face. As a potential mean of solving the emission of greenhouse gases, biochar (biomass-derived black carbon) has gradually become one of the most important research issues. All the paper researches around world show that biochar plays a powerful function and important role in soil amendment and environmental system. Biochar can be used as a soil amendment to improve soil structure, soil quality and increase crop production etc. The biochar approach provides a potential powerful solution: it allows us to sequestrate more carbon as well as reducing more pollutions of greenhouse gases from the environment and it will change the way of C cycles in the ecological system. As a soil ameliorant, it could increase the carbon stock sequestrations in soil all over the world. It provides the important solution to deal with the climate change problems. This paper reviews the latest important research, and offers the further research prospects. It aims to illustrate the important function of biochar in the soil and ecosystem, and offer the references for the further scientific biochar research which benefits for the further requiring study.