Difference of Nitrogen Uptake and Use Efficiency in Conventional Indica Rice Cultivars with Different Nitrogen Use Efficiency for Grain Output

[Objective] The study aimed to confirm difference of nitrogen uptake and used efficiency with different nitrogen use efficiency for grain output (NUEg) types of indica rice.[Method] 88 and 122 conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Dry matter weight (including root system, culm and sheath, leaves, panicle), nitrogen content of different organs, yield and its components were measured. The tested rice cultivars were classified into 6 types (i.e. A, B, C, D, E and F, A was the lowest, and F was the highest) based on their NUEg level by the MinSSw method.[Result](1)Difference of NUEg of the cultivars used in this study were very large; (2) No significant difference of N content at heading stage was observed among different NUEg types of indica rice. In the cultivars with higher NUEg, however, N content in leaf, stem-sheath and entire rice plant were lower at mature stage. (3)Cultivars with higher NUEg were characterized with lower N uptake before heading and at mature stage; (4) Cultivars with higher NUEg were characterized with higher N use efficiency in biomass production and harvest index. [Conclusion] The cultivars with higher NUEg showed lower N uptake and N content, while nitrogen use efficiency was higher.

Analysis of Yield Traits in Conventional Rice Varieties

From the breeding of conventional dwarf rice varieties in the 1960 s to rice heterosis utilization in the 1970 s, the improvement of yield traits has been a primary goal of rice breeding. However, the yield potential of multiple hybrid rice varieties bred successfully in recent twenty years is not significantly higher than that of early bred rice varieties. Due to continuous development and application of new germplasm resources, the yield of conventional rice varieties has been improved constantly. Currently, the yield of some conventional rice varieties is higher than that of hybrid rice. In order to clarify differences between the yield of conventional rice and hybrid rice, and reevaluate conventional rice varieties, in this study, conventional rice and hybrid rice combinations with the same genetic background were compared to analyze the yield and related traits of these 12 combinations. In the comparative experiments of 12 combinations of conventional rice and hybrid rice, the combinations in which yield of hybrid rice was significantly higher than that of conventional rice accounted for 41.7%; the combinations in which yield of conventional rice was higher than that of hybrid rice accounted for 16.6%; the combinations in which no significant differences were found between the yield of conventional rice and hybrid rice accounted for 41.7%. The yield of several conventional rice varieties was equal to or even higher than that of hybrid rice with the same genetic background. This study could provide theoretical reference for the genetic breeding, popularization and application of conventional rice.

Epigenetic Effects of Special Plant Nutritional Elements(SPNE) on Four Generations of Conventional Rice

[Objective] The epigenetic effects of special plant nutritional elements （SP-NE） on 4 generations of conventional rice were investigated. [Method] The 4 gener-ations of a conventional rice cultivar were al treated with the SPNE. The effects of SPNE on the yield of the 4 generations were investigated. From the 1st generation to the 4th generations, some seeds were treated with the SPNE and water alterna-tively, and some seeds were treated with the SPNE persistently. Under these condi-tions, the effects of SPNE on the yield of rice were studied. In addition, the epige-netic effects of spraying times of SPNE on the yield of rice within the same gener-ation were studied. According to the national standard for pol utant content in food （GB 2762-2012）, the heavy metal content, particularly the Cd content, and the pro-tein content in rice grains were determined. [Result] The increase and the epigenetic increase of yield of rice treated with SPNE were al enlarged generation by genera-tion. The yield differed among different plots even under the same SPNE treatment. But the yield increase was similar within the same plot. The epigenetic effects of spraying times of SPNE on the yield were also similar. The pol utant content in rice grains was al less than the limited content required by the national standard. The Cd content was lower and the protein content was higher in the rice treated with SPNE compared to that in the rice treated with water, indicating the rice treated with SPNE was more safe and nutritional. [Conclusion] We hope to provide a theo-retical basis for the production of conventional rice.

Value of Ecosystem Services in Conventional and Organic Rice Paddies:A Case Study in Wannian,Jiangxi,China

In the current study,the ecosystem services(ES) of conventional and organic rice paddies in Wannian,Jiangxi Province,China are investigated.First,the ES at the field level under organic and conventional paddies were investigated.Total economic value of ES in organic rice paddies was 30093.08 yuan RMB/ha per year and that of conventional rice paddies was 22 793.31 yuan RMB/ha per year.The total indirect value of ES was 14 813.7 yuan RMB/ha per year in organic rice paddies and 12 424.56 yuan RMB/ha per year in conventional ones.There were significant differences between organic and conventional rice paddies for the economic values.Then,this economic information was used to extrapolate and to calculate the total and indirect value of ES from rice paddies in Wangnian.The total and indirect economic values of ES from conventional rice paddies in Wannian were 6791 million and 3702 million yuan RMB per year respectively,and the total and indirect economic values of ES from organic rice paddies in Wannian were 1311 million and 646 million yuan RMB per year.If half the area had being converted to organic farming in Wannian,the total and indirect economic values of ES from conventional rice paddies were 3397 million and 1851 million yuan RMB per year,and the total and indirect economic values of ES from organic rice paddies were 5794 million and 2852 million yuan RMB per year.Finally,the total economic value of ES in rice paddies in Wannian was demonstrated through geographic information system techniques.

Assessment of System of Rice Intensification(SRI) and Conventional Practices under Organic and Inorganic Management in Japan

The system of rice intensification(SRI) is a production system that involves the adoption of certain changes in management practices for rice cultivation that create a better growing environment for the crop.This system was compared with conventional practices and assessed under organic and inorganic management.SRI practices showed significant response in root number,number of effective tillers per hill,days to flowering and harvest index.In addition,SRI was found effective in minimizing pest and disease incidence,shortening the crop cycle,and improving plant stand.Grain yield was not different from conventional method.Except for harvest index and plant lodging percentage,there were no significant effects from management treatments.Synergistic responses were noted when SRI practices were combined with organic management for plant height,number of effective tillers per hill,days to flowering and to maturity.The improved panicle characteristics,lower plant lodging percentage and higher harvest index that ultimately led to comparable grain yields.Net returns increased approximately 1.5 times for SRI-organic management regardless of the added labor requirements for weed control.However,comparatively higher grain yield from conventional-inorganic methods underscore the need for further investigations in defining what constitutes an optimum set of practices for an SRI-organic system specifically addressing grain yield and weed management.

Epigenetic Effects of Special Plant Nutritional Elements( SPNE) on Two Conventional Rice Cultivars

In this study, a series of experiments were conducted to investigate the epigenetic effects of special plant nutritional elements （SPNE） on two continuous generations of conventional rice. In the first generation, conventional rice cultivars were treated with SPNE and clean water, respectively; in the second generation, conventional rice cultivars were divided into four groups： （1） SPINE spaying in the first-generation and SPNE spaying in the second-generation; （2） clean water spaying in the first-generation and SPNE spaying in the second-generation; （3） SPNE spaying in the first-generation and clean water spaying in the second-generation; （4） clean water spaying in the first-generation and clean water spaying in the second-generation. The results showed that SPNE could improve fresh grain yield and dry grain yield of rice ; especially, dry grain yield of rice was improved more than fresh grain yield. Comparison results of two conventional rice cultivars in four groups confirmed that SPNE has epigenetic effects on rice in the second generation, thus improving the yield traits, chlorophyll content, protein content, amylase activity, peroxidase （POD） activity and superoxide dismutase （SOD） activity compared with control. Both these two conventional rice cultivars exhibited the best results in SPNE treatment. SPNE showed consistent trend of epigenetic effects on different rice cultivars but led to slightly different results.

The Current Breeding Situation and Development Strategies on High-quality Inbred Rice in Guangxi

According to the rice quality,production and resistance of 50 high-quality inbred rice varieties bred and examined and approved in Guangxi during the period 2000-2011,we analyze the current breeding situation and existing problems concerning high-quality inbred rice va- riety in Guangxi: the rice quality has been greatly improved,but the amylose content is still low; a series of scented rice varieties with high quality and high yield have been bred,such as Zhongguangxiang No. 1,Sanxiang 628,Guixiang No. 1,Liufengxiangzhan,Jiafuxiang No. 1, Zhaoxiang No. 1; the production of high-quality inbred rice during the period 2009-2011 was significantly enhanced,annually more than 66 00 kg / ha,but the disease resistance of rice variety bred was generally poor,and disease-resistant breeding stuck in the mud. Henceforth it is necessary to be oriented by the rice market,and take the rice type with long grain,high adhesive strength,medium-low amylose content and low chalkiness degree as the breeding objectives; introduce the existing high-quality variety resources with medium amylose content at home and abroad,then directly use them or innovate upon them as hybrid strain; take the thick-and-long-grain rice type as breeding objectives,and further improve the yield per unit area of high-quality inbred rice by improving the thousand-grain weight; increase capital investment,improve breeding techniques,strengthen disease-resistant and degeneration-resistant breeding,and improve the application of modern biotechnology in the breeding of high-quality inbred rice.

Breeding of High Quality Conventional Japonica Type Glutinous Rice Bancangjingnuo

Bangcangjingnuo is a new, mid-maturing conventional Japonica type glutinous rice variety bred by Hunan Rice Research Institute and Hunan Wucai Agricultural Science and Technology Development Co., Ltd. In 2017, the Hunan Crop Variety Examination and Approval Committee approved Bangcangjingnuo. The breeding process of this cultivar was expounded in this study. This cultivar is highly glutinous and waxy, it produces a stable high yield, and it possesses the quality of low temperature resistance. The theoretical yield of Bangcangjingnuo is 8 731.5 kg/hm^2, and the actual output is about 7 422.0 kg/hm^2 according to the 85% discount.Finally, we described the main points of cultivation technique from the perspectives of timely planting and strict seed sterilization.

Improvement of Rice Blast Resistance of High-Quality Rice Variety Xiangwanxian 13 by Molecular Marker-Assisted Selection

At present, most of high-quality rice varieties are susceptible to blast diseases. In this study, Gumei 2, a rice variety carrying broad-spectrum resistant Pi25 gene, was used as the donor, with Xiangwanxian 13 taken as the receptor and recurrent parent which is also of good quality but highly susceptible to rice blast, to improve the rice blast resistance of Xiangwanxian 13 by crossing and backcrossing based on molecular marker-assisted selection. The results showed that the resistance of the improved strains （i.e. Xiang C72, Xiang C76 and Xiang C77） to blast diseases had been enhanced signifcantly through feld resistance identifcation, equaling the resistance level of Gumei 2, and the main agronomic and quality-related traits of these improved strains had been restored to the level of Xiangwanxian 13, except the chalkiness and cooking-related traits, which suggested similar genomic loci of Xiang C72, Xiang C76 and Xiang C77 to those of Xiangwanxian 13. These three improved strains （i.e. Xiang C72, Xiang C76 and Xiang C77） can provide good intermediate materials for breeding elite varieties with high grain yields and superior blast resistance.

Appearance of Jiangzao 361, a Conventional Early Indica Rice Variety, in Throwing Demonstration Experiment and Its Matching Throwing Technique

In this paper, the characteristics of Jiangzao 361, as well as its appear- ance in throwing transplanting are introduced, and the high-yielding throwing tech- nique for Jiangzao 361 is summed up. On the basis of the experimental demon- stration, the corresponding matching throwing technique is put forward.

Breeding of High-Quality Late Rice Combination Taoxiuyouhuazhan

Taoxiuyouhuazhan is a high-quality fragrant late rice combination which was bred by the cooperation between Hu Nan Tao Hua Yuan Agricultural Technologies Co.,LTD.and Changde Institute of Agriculture and Forestry Science.With good yield,wide adaptability,resistance to rice blast,and the quality reaching third level of the national agricultural standard of Quality of Edible Rice Varieties.It has been authorized by the National Crop Variety Committee of the Ministry of Agriculture and Rural Affairs in February 2019.

Optimization of Conventional Combine Harvester to Reduce Combine Losses for Basmati Rice (<i>Oryza Sativa</i>)

A study was conducted at PAU Regional Research Station, Gurdaspur (Punjab) to investigate the design and operational parameters of threshing mechanism of conventional combine harvester for basmati crop. This study was aimed to investigate the suitable changes required in the self-propelled conventional combine harvester for harvesting the basmati crop with minimum grain losses. Field evaluation of experiment was carried out to assess the influence of independent design variable i.e., arrangement of spikes (AS) and independent operational parameters such as concave clearance (CC) and cylinder speed (CS). The study was aimed to enumerate various combining losses viz., extent of visible and invisible grain damage and threshing efficiency at different AS, CC and CS levels. The first year data recorded during 2017 were processed for the optimization during 2018. The results of the present study revealed that during 2017, maximum visible and invisible losses was 5.49% ± 0.33% and 28.07% ± 3.21%, respectively whereas after modification, these losses remained only 4.00% ± 0.80% and 24.07% ± 2.86%, respectively. The threshing efficiency remained above 99.31% ± 0.47%, for both years. Thus, optimization of combine harvester was able to save the visible grain damage by 60% to 83% and invisible grain damage by 6% to 16%, respectively during 2018 than the year 2017.

Study on Introduction Test of New Varieties of High Quality Conventional Rice in Yangjiang City, China

[Objective]The paper was to seek new varieties of high quality conventional rice suitable for Yangjiang area,Guangdong Province,China.[Method]In 2017,introduction test was performed with seven new varieties of high-quality conventional rice approved by Guangdong Province in recent years,including Huangsilizhan,Guangjingruanzhan,Heliyouzhan,Huahang 48,Limiaozhan,Lvyinzhan,Yuehesimiao,to investigate the main agronomic traits and yield of all varieties tested.[Result]The comprehensive performance of Lvyinzhan,Guangjingruanzhan,Limiaozhan and Huahang 48 was outstanding,showing the characters of good yield,excellent rice quality and strong stress resistance.[Conclusion]Lvyinzhan,Guangjingruanzhan,Limiaozhan and Huahang 48 are suitable for large-scale demonstration and promotion in Yangjiang area.

Drought-Tolerant Rice at Molecular Breeding Eras:An Emerging Reality

Rice(Oryza sativa L.)stands as the most significantly influential food crop in the developing world,with its total production and yield stability affected by environmental stress.Drought stress impacts about 45%of the world’s rice area,affecting plants at molecular,biochemical,physiological,and phenotypic levels.The conventional breeding method,predominantly employing single pedigree selection,has been widely utilized in breeding numerous drought-tolerant rice varieties since the Green Revolution.With rapid progress in plant molecular biology,hundreds of drought-tolerant QTLs/genes have been identified and tested in rice crops under both indoor and field conditions.Several genes have been introgressed into elite germplasm to develop commercially accepted drought-tolerant varieties,resulting in the development of several drought-tolerant rice varieties through marker-assisted selection and genetically engineered approaches.This review provides up-to-date information on proof-of-concept genes and breeding methods in the molecular breeding era,offering guidance for rice breeders to develop drought-tolerant rice varieties.

Breeding and Seed Production Techniques of New Aromatic Danxiangyouzhenliang Rice Variety with Good Quality and High Yield

Danxiangyouzhenliang rice is a high-quality rice variety derived from the hybrid breeding of Danxiang 12A and Xianghuixiangmiao R133.Its unique temperature-sensitive three-line characteristics endow it with significant advantages of high and stable yield,and its rice fragrance is exquisite and its taste is delicate.Danxiangyouzhenliang rice showed good resistance to rice blast and bacterial blight.On June 10,2021,Danxiangyouzhenliang rice passed the Guangxi Crop Variety Approval(Guishendao 2021074).Danxiangyouzhenliang rice is suitable to be planted as early and late rice in southern,central and northern Guangxi.This study summarized the breeding process and high-yielding seed production techniques of Danxiangyouzhenliang rice,in order to provide useful reference for rice breeders and growers.

Analysis of the Nationally Registered Rice Varieties in the Last Decade

The nationally registered rice varieties during 2006-2015 were analyzed and there were 49.4 varieties on average annually registered in the last decade. In terms of the structure of varieties, there was a decreasing trend for the proportion of three-line hybrid rice varieties but a rapid increase for that of two-line hybrid rice varieties. The percentage of rice varieties developed by scientific research institu- tions was decreasing but that developed by seed companies kept a rapid increase, indicating the commercial breeding conducted by seed companies has become a principal model in rice breeding. With regard to grain quality of varieties, the con- ventional rice varieties showed an increasing trend while the hybrid rice varieties had a decreasing trend in the proportion of high quality varieties, indicating hybrid rice needs improving more in grain quality in breeding programs.

Effect of Silicon and Nitrogen Nutrition on Pest and Disease Intensity in Rice

Nutrition management is the most important for high yield production but it may affect the response of rice plants to pest and diseases due to the change of microclimate under rice plant canopy. The knowledge of nutrition management and its relation with pest and diseases are basis for setting up a high yield production system. Most of the pest and disease control procedures used by farmers can be considered as soil fertility management and these nutrition practices can have impact on the physiological susceptibility of crop plants to pest and diseases by affecting the plant resistance. Silicon content of plants is particularly effective against pest and diseases in rice and certain rice genotypes are more efficient accumulators of silicon, thus making them more resistant. In the absence of natural heritable resistance in rice varieties, resistance could be induced by altemate strategies to suppress certain pest and pathogens. Hence experiments were carried out in two stages during kharif 2010 and 2011 to assess the concentration of silicon in the index leaves of rice plant utilizing 133 varieties in four locations. The silica content of promising varieties ranged from 1.50% to 3.20%, 1.60% to 3.15%, 1.49% to 3.20% and 1.55% to 3.06% with a mean values of 2.50%, 2.48%, 2.51% and 2.43% at Jagtial, Warangal, Rajendranagar and Rudrur centres of Telangana region and not much variation in mean silica content in index leaves at different places. The overall yield from four locations ranged from 2,653 kg/ha to 6,860 kg/ha with a mean of 5,624 kg/ha. The yields recorded at Jagtial, Warangal, Rajendranagar and Rudrur centres ranged from 2,886 to 7,198, 2,653 to 6,831, 2,653 to 6,860 and 4,399 to 5,950 kg/ha, respectively. The lowest mean yield 5,069 kg/ha was noticed at Rudrur and the highest yield 5,940 kg/ha was found at Warangal. The variations in yields might be due to genotypic variations and also due to variations in climatic conditions of different locations.

Comparisons of Metabolic Profiles for Carbohydrates,Amino Acids,Lipids,Fragrance and Flavones During Grain Development in indica Rice Cultivars

We used a widely targeted metabolomics approach to examine the metabolic changes in three pedigreed indica cultivars(Meixiangzhan 2,Meisizhan and Qixinzhan),with different eating qualities,at 8,15 and 30 d after flowering(DAF)to explore the formation mechanism of rice eating and nutritional qualities at a global metabolic level.A total of 623 metabolites were identified,and results showed that metabolic variations among rice cultivars decreased with grain developmental stage,suggesting that sufficient carbohydrate and amino acid supply during grain development may contribute to excellent rice eating and nutritional quality formation.Lysophosphatidylcholines 19:0 and 16:1 were beneficial for excellent eating quality formation during grain development.Rice fragrance was attributed mainly to spermidine andγ-aminobutyric acid.Rice cultivars with excellent eating quality at 15-30 DAF had relatively higher flavone content,possibly because they had adequate carbohydrate and amino acid contents during grain development.These results provided insight into the mechanisms for establishing rice eating and nutritional qualities during grain formation at a global metabolic level,and can be applied towards improving rice quality.

New Early Rice Variety Jiangzao 361

Jiangzao 361 was bred by Institute of Food and Oil Crops, Nanchang Ac- ademy of Agricultural Sciences and Jiangxi Kewei Institute of Agricultural Crops from Jiazao 311 and intermediate material Z6340 through sexual hybridization. This variety has proper plant shape, wide and straight flag leaf and strong and thick stem, with the advantages of more grains per panicle, close seeds, high seed set- ting rate and good color in maturation stage. In December 2014, the variety passed the examination and approval by Jiangxi Crop Variety Approval Committee in 2014. In this study, the characteristics of the variety, and its high-yielding cultivation tech- nique of direct seeding in the rice field in Jiangxi Province and seed reproduction technique were introduced.

2016—2023年广西优质常规稻育种现状及发展对策

分析了广西2016—2023年审定的135个常规稻品种主要性状和产业发展形势,认为广西优质常规稻品种存在稻瘟病抗性水平低、稻米品质指标协调性差、主效基因缺乏、同质化严重、低镉型品种选育滞后、销售及转让价格低等问题,对配套栽培技术的研究和推广也不足。针对当前广西优质常规稻育种及产业存在的问题提出解决对策,如加强分子育种,提高品种品质和稻瘟病抗性,加快选育镉低积累品种,加大优质稻品种推广力度,研发和推广配套保优高产栽培技术,打造高端品种优势品牌。