Sponsor(s): Chinese Academy of Agricultural Sciences；Chinese Association of Agricultural Science Societies
24 issues per year
Current Issue: Issue 24, 2016
Scientia Agricultura Sinica, the 1st in Comprehensive Agricultural Science, is supervised by Ministry of Agriculture of PRC, and sponsored by Chinese Academy of Agricultural Sciences; Chinese Association of Agricultural Science Societies. Scientia Agricultura Sinica, launched in 1960, is a leading peer-reviewed and mufti-disciplinary journal and published semi-monthly in Chinese with English title, abstract, figures, tables and references. It aims to publish those papers that are influential and will significantly advance scientific understanding in agriculture fields worldwide. The scope covers Crop Genetics, Breeding, Germplasm Resources; Physiology, Biochemistry, Cultivation, Tillage Plant Protection; Soil & Fertilization, Agro-Ecology & Environment, Bio-energy; Animal Science, Veterinary Science, Agricultural Information Science; Food Science; Agricultural Economics and Management; Agricultural Sustainability. The journal is included in JST, CA and CSCD.
Editor-in-Chief Wan Jianmin Associate Editor-in-Chief Zou Ruicang Tang HuaJun Wu Kongming Guo YuYuan Geng Xu Sun Tan Executive Editor Lu Wenru
Effects of Fertilizer Levels on Nitrogen Utilization Characteristics and Yield in Rice Cultivars with Different Nitrogen Use Efficiencies
Scientia Agricultura Sinica,2016,Vol 49,No. 24
[Objective] The relationship of grain yield and nitrogen (N) utilization characteristics in rice cultivars with different N use efficiencies (NUE) was studied under different fertilizer levels. This study will provide reference data for the cultivation of high-NUE rice cultivars and rice breeding. [Method] For this purpose, two rice cultivars differing in NUE were chosen for this study, one with high-NUE (Dexiang 4103) and the other with low-NUE (Yixiang 3724). Fertilizer was applied at three levels, including low (75 kg N·hm−2, 37. 5 kg P2O5·hm−2, 75 kg K2O·hm−2, N1P1K1), medium (150 kg N·hm−2, 75 kg P2O5·hm−2, 150 kg K2O·hm−2, N2P2K2), and high rates (225 kg N·hm−2, 112.5 kg P2O5·hm−2, 225 kg K2O·hm−2, N3P3K3). A no-N treatment was included for each level as the control. The effect of fertilizer levels on grain yield and N utilization characteristics in rice cultivars with different NUEs, and its absorption, translocation and distribution of N from heading and maturity stage were studied. [Result] The results showed that rice cultivars with different NUEs and fertilizer levels significantly affected accumulation, translocation and distribution of N at main growth stages and each growing stage, N utilization characteristics and grain yield. Rice cultivars exhibited markedly stronger effects on N recovery efficiency, 1 000-grain weight, and total spikelets number, compared to fertilizer application levels. An opposite trend was observed in N accumulation at different growth stages, N translocation in leaves and stem-sheaths at grain filling stage, and grain yield. Compared with N1P1K1, N2P2K2promoted N accumulation at main growth stages and each growing stage, increased N harvest index, and facilitated N translocation in vegetative organs at grain filling stage, ultimately improved grain yield and NUE in both rice cultivars. The N2P2K2 treatment produced higher yield than other fertilizer treatments of the same rice cultivars and thus was regarded as the optimal NPK fertilizer application. Applying the N3P3K3treatment resulted in a higher N retention in leaves and stem-sheaths at grain filling stage and a lower N translocation conversion rate of vegetative organs, thereby reduced the grain yield and NUE. The results also showed that total spikelets number, high seed setting rate, N accumulation at main growth stages, and N harvest index, more than those of low-NUE rice cultivar. However, 1000-grain weight was not unique characteristics of rice cultivar with high-NUE. In addition, compared with low-NUE, the high-NUE rice cultivar was more beneficial to N translocation and redistribution from leaves and stem-sheaths to panicle at grain filling stage, and then improved grain yield and NUE, especially, N transportation efficiency of stem-sheath in high-NUE rice cultivars had a significant positive correlation (r = 0.699*−0.743*) with different indexes of N physiological efficiency, N recovery efficiency, and N agronomic efficiency, and which is the important reason for high-NUE rice cultivar further to increase yield and NUE. The N transportation efficiency of stem-sheath might be a candidate indicator for high yield and high-NUE in different varieties of rice. To improve N transportation efficiency of stem-sheath in high NUE from heading to maturity stage, this is an important way to promote rice yield at the same time as increasing N use efficiency. [Conclusion] Compared to low NUE, the results suggest that the high-NUE is more beneficial to N translocation and redistribution from stem-sheath to panicle, high total spikelet number and seed setting rate at grain filling stage, which is the key factor behind yield gap. High-NUE and suitable N2P2K2combined application was considered to be optimum under the experimental conditions. Correlation analysis indicated that the increase of N accumulation, promote N translocation of leaves and stem-sheath during the period from heading to maturity, especially improve the N transportation efficiency of stem-sheath is helpful to the high-yield and high-NUE in rice.
Quality Variation of National Tested Varieties in Northern Winter Wheat Region and Yellow-Huai River Valley Winter Wheat Region from 2000 to 2015
Scientia Agricultura Sinica,2016,Vol 49,No. 24
[Objective] The present study was conducted to analyze the quality variation of tested varieties in regional trials in Northern winter wheat region and Yellow-Huai River Valley winter wheat region, and to discuss the status and trends of wheat quality improvement in breeding process. [Method] Test weight, protein content of grain, wet gluten content and sedimentation index of flour, rheological properties of 1 418 samples, from 985 tested varieties in seven groups, were detected, and quality variations of strong gluten, medium-strong gluten and medium gluten varieties in each group were analyzed. [Result] The percentages of strong gluten, medium-strong gluten and medium gluten varieties in each group were varied, and the ratio of medium gluten variety was 78% in average, while those of strong gluten and strong-medium gluten were relatively low, with an average of 11%, respectively. Ratios of strong gluten in irrigation group in northern part of Yellow-Huai River Valley winter wheat region (13%), winter-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region (11%), and spring-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region (16%) were higher than those in Northern winter wheat region (6%) and dryland group in Yellow-Huai River Valley winter wheat region (7%), and the ratio of medium-strong gluten in winter-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region (20%) was higher than any other groups, while the ratio in Northern winter wheat region (5%) was the lowest. For the approved varieties, the ratio of strong gluten varieties (4%) and strong-medium gluten varieties (10%) in winter-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region was the highest among 7 groups, and those of spring-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region were followed by 3% and 6%, respectively. The ratio of medium gluten varieties in winter-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region (17%), and spring-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region (19%) were higher than those of the other groups. It was qualified for medium gluten wheat with relatively high protein content and low protein quality in each group, which was consistent with high percentage of medium gluten varieties. There were wide variations in variety qualities among the groups. Test weight of varieties in average in northern part of Yellow-Huai River Valley winter wheat region, winter-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region, and spring-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region was higher than those of the other groups, while the protein content of flour in average was just the opposite, and the stability time in average in Northern winter wheat region and dryland group in Yellow-Huai River Valley winter wheat region was higher than those of the others. The extension area in average in spring-wheat-irrigation group in southern part of Yellow-Huai River Valley winter wheat region was the highest among these groups. Quality variation trends in different years and groups were similar. The test weight, stability time, extension area and max. resistance showed increasing trends while water absorption was decreased, protein content and wet gluten content changed little, and sedimentation index increased first and decreased afterwards. [Conclusion] Quality improvement in wheat showed a slow progress in China, and breeding level was imbalanced in groups. As a result, wheat quality and variety structure were influenced in corresponding wheat-producing region. It is necessary to select new variety with high quality, and to improve variety structure and wheat quality.
Scientia Agricultura Sinica,2016,Vol 49,No. 24
[Objective] Rice foot rot, caused by Dickeyazeae, is one of the important bacterial diseases on rice. Bacteria flagella is an important movement organ, so far, the mechanism of the flagellar system, flhDC and fliA and their regulatory mechanisms are unclear in Dzeae. To clarify the function of these flagellum genes is helpful for further understanding the pathogenicity of integrated control network in D. zeae, developing new drug action targets and making disease prevention and control strategies. The objective of this study is to investigate the function of flagellar system of flhDC and fliA in D. zeae. [Method] A set of primers were designed based on the genomic DNA of wild strain EC1 of D. zeae. The upstream and downstream fragments of target genes flhDC and fliA to be knocked out were amplified by PCR, respectively. The upstream and downstream fragments were mixed as a template, and then the fusion fragments that lack of flhDC and fliA were obtained by PCR. After dualenzyme digestion and purification, the fusion fragments were connected to the suicide vector p KNG101, suicide recombinant plasmids p KNG-ΔflhDC and p KNG-ΔfliA with reverse selection marker gene sac B were constructed, then transferred into wild strain EC1, respectively, by tri-parental mating, so the gene deletion mutants ΔflhDC and ΔfliA were constructed after two alleles homologous recombination screening and PCR detection and sequencing verification. The biological characteristics such as extracellular enzyme, toxin, motility, biofilm, virulence to rice and HR on tobacco were compared and analyzed. In addition, bacterial total RNA was extracted, and a real-time quantitative PCR (q RT-PCR) was carried out using 16Sr DNA as internal control for normalization. Then the expression of downstream genes flhD, flhC, fliA and fliC in ΔflhDC and ΔfliA was compared. [Result] Two target gene deletion mutants ΔflhDC and ΔfliA were constructed successfully by genetic manipulation. Phenotypic test results showed that the motility and biofilm formation of wild strain EC1 were very strong, while the motility and biofilm formation of the ΔflhDC and ΔfliA were decreased obviously. The wild strain EC1 had a strong inhibitory effect on rice seed germination, while ΔflhDC and ΔfliA significantly reduced the inhibition of rice seed germination. The rice plants inoculated with the wild strain EC1 showed a brown spot and a large extent of rottenness, while rice plants with ΔflhDC and ΔfliA inoculation only showed water-brown lesions around the inoculated sites. It indicated that ΔflhDC and ΔfliA significantly reduced the virulence to rice plant. Further phenotypic results showed that the activities of extracellular enzymes, toxin and the ability to cause HR on tobacco were not different significantly between the mutants and the wild strain. The results of qRT-PCR showed that in the mutant ΔflhDC, the flhDC and the fliA did not express, while the expressions of the fliA and the fliC decreased obviously compared with the wild strain. In addition, the flhD, flhC and the fliA in the mutant ΔfliA did not express, but the expressions of the fli C decreased obviously. [Conclusion] The flhDC operon, which regulates the expression of the bacterial flagellum genes, and the fliA, which expresses flagellin specific factor σ28, are important components of the bacterial flagellar system gene cluster. The genes flhDC and fliA significantly affect the motility, biofilm and the germination of rice seeds, and play an important role involving in the virulence in D. zeae.
Effect of Micro Ridge-Furrow with Whole Field Plastic Film Mulching and Bunching Seeding on Water Consumption Characteristics and Water Use Efficiency of Winter Wheat in Semiarid Areas of Northwest Loess Plateau
Scientia Agricultura Sinica,2016,Vol 49,No. 24
[Objective] Precipitation is inadequate in arid and semiarid areas of Northwest Loess Plateau. Especially, the non-available precipitation, with daily rainfall less than 10 mm, accounts for more than 50% in winter wheat growth period. Consequently, how to use this part of precipitation sufficiently is a key method to increase the rainfall use efficiency and yield stability of winter wheat in this area.[Method] The winter wheat cultivar Zhongliang 1 was selected as test material, and a field experiment was conducted from 2011 to 2015 on Northwest Loess Plateau (104°36′E, 35°35′N). The designed four treatments were (1) micro ridge-furrow with whole field plastic film mulching and bunching seeding (PRF), (2) whole field soil plastic mulching and bunching seeding (PMS), (3) sand mulching and bunching seeding (SM), and (4) bunching seeding without mulching (CK). The seasonal soil water content in 0–200 cm soil layer, aboveground biomass, yield and its components of winter wheat were recorded; the wheat periodical water consumption in 0–200 cm soil layer and water use efficiency were calculated to understand the effect of PRF on soil water storage, water consumption characteristics, yield and water use efficiency of winter wheat. [Result] The four-year average soil water storage of PRF at sowing and regreening stages was higher than PMS, SM, CK by 24.3, 38.8, 7.4 mm and 18.2, 26.9, 67.8 mm, respectively. PRF averagely increased wheat evapotranspiration from heading to filling stage by 36.0 mm than PMS. As compared with SM and CK, it increased by 12.1 mm and 16.7 mm, 40.8 mm and 37.6 mm from regreening to heading and from filling to maturity, respectively. The aboveground biomass of PRF was higher than PMS by 2.2%–15.4% at seeding, heading, filling and mature stages, and the significant difference was observed at filling stage in 2011–2012, and at seedling and heading stages in 2014–2015. As compared with CK and SM, the aboveground biomass of PRF was significantly higher at the four growth stages. spike number per hectare, grain number per spike and 1 000-grain weight were in the order: PRF > PMS > SM in four experimental years, and the significant difference was not observed among the three treatments, but they were significantly higher than that in CK. The yield of PRF was the highest among the four treatments, and it reached 4 373.6–4 950.0 kg·hm−2, increasing by 2.4%–12.7% as compared with that of PMS; besides, significant difference was observed in 2012–2013 and 2014–2015, respectively. It was significantly higher than those in SM (except for 2012–2013) and CK (increased by 35.8%–43.8%) in four experimental years. The water use efficiency of PRF increased by 0.4%–12.8% as compared with PMS, and significant difference was observed except for the year 2013–2014; besides, it was also significantly higher than those in SM (except for 2014–2015) and CK (significantly increased by 8.1%–42.1%) in four experimental years. [Conclusion] PRF could use small rainfall (daily rainfall amount < 10 mm) efficiently, increased the soil water storage in 0–200 cm profile at sowing and regreening stages, improved the wheat evapotranspiration at filling stage, and increased the spike number per hectare, weight and 1 000-grain weight, thus resulting in the increase of grain yield and water use efficiency. Consequently, the micro ridge-furrow with whole field plastic film mulching and bunching seeding was the better cropping pattern for high yield and efficiency of winter wheat in semiarid areas of Northwest Loess Plateau.