Rice seed variety classification is crucial for seed quality control and breeding, yet practical deployment is often limited by the computational and memory demands of modern deep models. We propose SimpleEfficientCNN (SimpleEfficient: simple & efficient; CNN: convolutional neural network), an ultra-lightweight convolutional network built on depthwise separable convolutions for efficient fine-grained seed classification. Experiments were conducted on three datasets with distinct imaging characteristics: a self-constructed Guangdong dataset (7 varieties; 10,500 seeds imaged once and expanded to 112 K images via post-split augmentation), the public M600 rice subset (7 varieties; 9100 original images expanded to 112 K images using the same post-split augmentation pipeline for scale-matched comparison), and the International dataset (75 K images; official train/validation/test split provided by the original release and used as-is without any preprocessing or augmentation, 5 varieties). SimpleEfficientCNN achieved 98.52%, 88.07%, and 99.37% accuracy on the Guangdong, M600, and International test sets, respectively. With only 0.231 M parameters (≈92× fewer than ResNet34), it required 20.5 MB peak GPU memory and delivered 2.0 ms GPU latency (RTX 4090D, batch = 1, FP32) and 1.8 ms single-thread CPU median latency (Ryzen 9 7950X3D, batch = 1, FP32). These results indicate that competitive accuracy can be achieved with substantially reduced model size and inference cost, supporting deployment in resource-constrained agricultural settings.

'Heguang Simiao'is a new conventional rice variety with high harvest index and excellent comprehensive traits.It has a good plant type,high yield and good rice quality.When participating in the regional test of Guangdong Province and the national late indica rice area in the middle and lower reaches of the Yangtze River,the rice quality reached the first grade of high quality awarded by the Ministry and the first grade of high quality in the agricultural industry.The grains of rice are crystal clear and lustrous,the maximum yield per 667 m² of the regional trial reached 608.6 kg.It was approved by Guangdong Province in 2019,it was approved by the state twice successively in 2020 and 2023.Meanwhile,the variety is also an excellent hybrid rice restorer line.Seven hybrid rice combinations,including'Quanyou Heguang Simiao'and'Huiliangyou Guangsimiao',have been developed and approved based on it as the male parent.These combinations are characterized by high and stable yield,good quality and good adaptability,demonstrating the"core"role of'Heguang Simiao'seedlings as superior parent.'Heguang Simiao'seedlings can be promoted and cultivated in seven regions including Guangdong,Guangxi,Hainan,Fujian,Jiangxi,Hunan and Zhejiang.It was selected as a leading agricultural variety in Guangdong Province in 2024-2025,and is currently a key promoted variety in cities such as Huizhou,Zhongshan city and Haifeng County in Guangdong Province.It has a good prospect for promotion and application in the double-cropping rice areas of South China and the late indica rice areas in the middle and lower reaches of the Yangtze River.

(1) Background: The harvest index is important for measuring the correlation between grain yield and aboveground biomass. However, the harvest index can only be measured after a mature harvest. If it can be obtained in advance during the growth period, it will promote research on high harvest indices and variety breeding; (2) Methods: In this study, we proposed a method to predict the harvest index during the rice growth period based on uncrewed aerial vehicle (UAV) remote sensing technology. UAV obtained visible light and multispectral images of different varieties, and the data such as digital surface elevation, visible light reflectance, and multispectral reflectance were extracted after processing for correlation analysis. Additionally, characteristic variables significantly correlated with the harvest index were screened out; (3) Results: The results showed that TCARI (correlation coefficient −0.82), GRVI (correlation coefficient −0.74), MTCI (correlation coefficient 0.83), and TO (correlation coefficient −0.72) had a strong correlation with the harvest index. Based on the above characteristics, this study used a variety of machine learning algorithms to construct a harvest index prediction model. The results showed that the Stacking model performed best in predicting the harvest index (R2 reached 0.88) and had a high prediction accuracy. (4) Conclusions: Therefore, the harvest index can be accurately predicted during rice growth through UAV remote sensing images and machine learning technology. This study provides a new technical means for screening high harvest index in rice breeding, provides an important reference for crop management and variety improvement in precision agriculture, and has high application potential.

【Objective】This study aims to compare the effects of ratoon and direct seeding cultivation methods on rice yield, and identify high-performing ratoon rice and direct-seeded rice varieties. It will provide important references for variety selection of late-season ratoon rice and direct-seeded rice in South China, and offer theoretical support for regional variety optimization and the application of simplified cultivation techniques.【Method】Field experiments were conducted in Guangzhou using 15 conventional rice varieties for ratoon cultivation and 15 varieties (seven conventional and eight hybrid) for direct seeding. In the ratoon experiment, the main crop was manually harvested at maturity, leaving a 15 cm stubble, and the ratoon crop was allowed to regrow naturally. Yields of both the main and ratoon crops were measured based on 18 plants, and growth durations were recorded. In the direct-seeding experiment, both transplanting and direct-seeding methods were applied to assess seedling establishment rate, heading date, maturity period, plant height, and yield performance.【Result】All 15 ratoon varieties exhibited lower yields than their main crops, with an average reduction of 33.69%. 'Hefuzhan' achieved the highest ratoon yield (393.00 g) and annual total yield (877.58 g), followed by 'Yueyitang 1. Henongsimiao' 'Hefuzhan' and 'Yueyitang 1' also had the longest ratoon growth duration (80 days). In the direct-seeding trial, 'Yuenuo 2' recorded the highest seedling establishment rate (77.34%). 'Tailiangyou 1' 'Yuehesimiao', and 'Hefuzhan' exhibited the longest growth duration (111 days) under direct seeding, while 'Yuenuo 2' 'Yuefujinzhan' and 'Huanghuazhan' matured 6-7 days earlier than their transplanted counterparts. The highest yield under direct seeding was obtained by 'Wolianyouyueyasimiao' (646.17 g).【Conclusion】Based on ratoon yield and total productivity, 'Hefuzhan' and 'Yueyitang 1' are recommended as promising ratoon rice varieties for Guangdong and the broader South China region. Considering seedling establishment and yield performance, 'Yuenuo 2' 'Yuefujinzhan' and 'Huanghuazhan' are identified as representative varieties suitable for direct-seeding cultivation.

High harvest index (HI), defined as the grain yield-to-biomass ratio (>= 0.55), reflects a well-balanced source-sink relationship. It is a key trait in rice high-HI breeding programs, which has proven to be a successful strategy for developing super high-yield rice varieties. However, its genetic basis remains elusive. This study conducted QTL analysis for HI-related traits using a recombinant inbred line (RIL) population derived from a cross between a geng/japonica cultivar, Lijiangxintuanheigu (LTH), and a high HI xian/indica variety, Yuenongsimiao (YNSM). A high-density genetic map with 6674 bin markers identified 97 QTLs across 12 HI-related traits, forming 13 QTL clusters that affect the source-sink related traits in rice. These bin markers were converted from 1,009,324 high-quality SNPs sourced from the sequenced RIL population. Notably, qRSC1 (QTL cluster of rice source capacity 1), which included qFLL1, qSTW1, qBM1.2, and qHI1, was tightly linked to the semi-dwarf gene sd1 and collectively shaped the high HI plant architecture of YNSM. In contrast, qRSC3(qFLL3/qFLW3/qSTW3/qBM3.1/qHI3.1) exhibited an opposite effect and positively regulated source-related traits. Among nine QTLs associated with yield per plant (YPP), only qYPP2.2, part of qRSS2 (QTL cluster of rice sink size 2), was consistently detected over two consecutive years. qRSS2 governed sink size by integrating multiple yield-related QTLs, including qYPP2.2. Overall, qRSC1, qRSC3, and qRSS2 collectively optimized source-sink balance, enabling YNSM's high HI and high yields. These findings provide insights into the genetic basis of high HI in YNSM and may facilitate breeding high-yielding rice with superior HI.

Objective High quality is one of the core objectives in rice breeding, encompassing multiple aspects such as processing quality, appearance quality, cooking and eating quality, as well as nutritional quality. ‘Yuehesimiao’ is a high-quality main rice variety developed by the Rice Research Institute of Guangdong Academy of Agricultural Sciences. It exhibits strong lodging resistance, high stress tolerance, and excellent grain quality, and has been widely adopted. This study was aimed to systematically analyze the grain quality and associated genotypes of ‘Yuehesimiao’, further explore its superior traits, and provide a theoretical support for rice breeding and variety improvement.MethodUsing high-quality varieties ‘Yuexiangzhan’ and ‘Yuzhenxiang’ as controls, the grain quality traits of ‘Yuehesimiao’ (including grain shape, amylose content, gel consistency) were measured, and its starch viscosity profile (including peak viscosity, cool paste viscosity and setback viscosity, etc.) were characterized. Simultaneously, PCR amplification and genotyping were performed for quality-related genes. Meanwhile, the application potential of ‘Yuehesimiao’ in quality breeding was explored. ResultThe grain shape of ‘Yuehesimiao’ was intermediate between those of the two control varieties, with its grain morphology primarily governed by gs3 and gw7 genes. The processing quality traits of ‘Yuehesimiao’ were excellent, featuring low amylose content and high gel consistency. Its superior cooking and eating quality was associated with Wxb gene. Additionally, ‘Yuehesimiao’ was demonstrated with high protein and fatty acid contents, with these characteristics being particularly pronounced under early-season cultivation conditions. The quality characteristics of hybrid and conventional rice varieties developed using ‘Yuehesimiao’ as a restorer line or a founder parent were excellent. Conclusion‘Yuehesimiao’ is a medium-to-long grain rice variety with excellent appearance quality and superior processing quality. These findings provide a theoretical basis for developing new rice varieties featuring synergistic improvement of yield, stress resistance, and grain quality.

Aroma is a crucial determinant of rice taste quality, with volatile organic compounds (VOCs) playing a key role in defining this characteristic. However, limited research has explored the dynamic changes in these aromatic substances during the ripening stages of rice grains. In this study, we analyzed VOCs in rice grains across four ripening stages post-flowering using headspace solid-phase microextraction combined with gas chromatography–mass spectrometry (HS-SPME-GC-MS). A total of 417 VOCs were identified, among which 65 were determined to be key aroma-active compounds based on relative odor activity value (rOAV) analysis. Most of these aroma-active compounds exhibited an accumulation pattern as the grains matured. Notably, 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone and 2-Methyloxolan-3-one had the largest rOAV values. Additionally, (Z)-6-nonenal, (Z,Z)-3,6-nonadienal, 2-thiophenemethanethiol, 5-methyl-2-furanmethanethiol, 2,2,6-trimethyl-cyclohexanone, and 3-octen-2-one were identified as potential key markers for distinguishing rice-grain maturity stages. Moreover, 2-acetyl-1-pyrroline (2-AP), heptanal, and 1-nonanol were identified as marker metabolites differentiating aromatic from non-aromatic brown rice. These findings contribute to a deeper understanding of the dynamic variation and retention of aroma compounds during rice-grain ripening, and they offer valuable insights into the improvement of fragrant rice varieties.

Grain shape in rice (Oryza sativa L.) is a complex trait governed by multiple quantitative trait loci (QTLs). To dissect the genetic basis of rice shape, QTL analysis was conducted for milled rice grain width (MGW), milled rice grain length (MGL), and milled rice length-to-width ratio (MLWR) using a recombinant inbred line (RIL) population of F10 and F11 generations derived from a cross between Yuexiangzhan and Shengbasimiao. A high-density genetic map consisting of 2412 bins was constructed by sequencing 184 RILs, spanning a total length of 2376.46 cM. A total of 19 QTLs related to MGL, MGW, and MLWR were detected under two environments. The range of phenotypic variation attributed to individual QTL ranged from 1.67% to 32.08%. Among those, a novel locus for MGL, MGW and MLWR, designated as qMLWR3.2, was pinpointed within a specific ~0.96-Mb region. Two novel loci for MGW and MLWR, qMLWR11.1 and qMLWR11.2, were verified within ~1.22-Mb and ~0.52-Mb regions using three RIL-developed populations, respectively. These findings lay the foundation for further map-based cloning and molecular design breeding in rice.

Rice is one of the most important crops in the world,and safe production of rice is related to food safety issues.Rice blast,caused by Magnaporthe oryzae,is a worldwide fungal disease that causes serious losses to rice production.Compared with chemical pesticides control,the breeding and application of disease-resistant cultivars is the most economical and effective way to control the disease.However,the complex and diverse population of blast fungus in the field,excessive use of chemical pesticides,change of temperature environment and other factors cause rapid evolution of M.oryzae isolates,and the resistance of cultivars can only last for 3-5 years.Magnaporthe oryzae generates new races through the mutation of avirulent genes,which can escape or suppress the immune system of rice,causing infection and disease.At present,26 avirulent genes in blast fungus have been identified,and 14 of them have been cloned,which plays an important role in the infection and colonization of pathogens and in interfering with the immune response of host plants.Further studies on the interaction mechanism of M.oryzae effector protein and rice resistance protein have also been conducted.Understanding the pathogenic mechanism of blast fungus and molecular mechanism of its interaction with rice will help to better understand the pathway of pathogens and the immune response of plant disease resistance genes,to formulate more efficient and green control measures.This review summarized the process of M.oryzae effector protein translocation and secretion in rice cells,the research advances in the interaction between effector proteins and disease-resistance proteins and the regional distribution of effector proteins.And the opportunities and challenges in current researches were discussed and prospected,with an aim to provide references for the molecular mechanism of the interaction between rice and blast fungus,disease-resistance breeding and disease prevention and control strategies.

Rice quality is one of the main targets of rice breeding and is a complex trait that involves grain appearance, milling, cooking, eating and nutritional quality. For many years, rice breeding has contended with imbalances in rice yield, quality, and disease and lodging resistance. Here, the milling and appearance quality, cooking quality, starch rapid viscosity analyzer (RVA) profile, and nutritional quality of grains of Yuenongsimiao (YNSM), an indica rice variety with high yield, high quality and disease resistance, were determined. YNSM had excellent appearance and quality, with low amylose contents and high gel consistency, and these characteristics exhibited significant correlations with the RVA profile such as hot paste viscosity, cool paste viscosity, setback viscosity, and consistency. Moreover, 5 genes related to length-to-width ratio (LWR) as well as the Wx gene were used to detect the main quality genotype of YNSM. The results showed that YNSM is a semilong-grain rice with a relatively high brown rice rate, milled rice rate and head rice yield and low chalkiness. The results indicated that the LWR and food quality of YNSM might be related to gs3, gw7 and Wxb. This study also reports the quality characteristics of hybrid rice developed using YNSM as a restorer line. The quality characteristics and the genotype for grain quality determined through gene analysis in YNSM may facilitate the breeding of new rice varieties that achieve a balance of grain yield, resistance and quality.

[Objective]By measuring and analyzing the physical characteristics of the basal stems of rice,the relationship between these traits and the stem breaking resistance was explored,and the core traits affecting the basal stem breaking resistance of rice were identified,providing a theoretical basis for the breeding of rice lodging-resistant varieties.[Method]The study analyzed the lodging resistance-related agronomic traits,including plant height,single plant bending resistance,basal internode breaking resistance,and stem structure,of the rice variety Yuehesimiao,the lodging-susceptible variety Xiangyaxiangzhan,and Yuehesimiao×Xiangyaxiangzhan F2 segregation populations.The influence of each trait on lodging resistance of rice was evaluated by correlation coefficient.[Result]There are significant differences in lodging resistance between the two varieties of Yuehesimiao and Xiangyaxiangzhan.The N2(second internode from the base)breaking resistance(16.58 N),N2 wall thickness(1.02 mm),N2 filling degree(0.19 g/cm),and N2 stem diameter(6.21 mm)of Yuehesimiao are significantly larger than those of Xiangyaxiangzhan(N2 breaking resistance:9.93 N,N2 wall thickness:0.66 mm,N2 filling degree:0.11 g/cm,N2 stem diameter:4.60 mm).The N2 breaking resistance,N2 length,N2 stem diameter,stem wall thickness,fresh weight and filling degree of the F2 population show continuous distribution and are controlled by polygenes.The correlation analysis results of the F2 population show that,N2 breaking resistance is positively correlated with plant height(r=0.18),N2 breaking resistance is significantly positively correlated with N2 wall thickness(r=0.75**).N2 breaking resistance is significantly positively correlated with N2 filling degree(r=0.67*).N2 breaking resistance is positively correlated with N2 minor axis(r=0.52)and N2 stem diameter is negatively correlated with N2 length(r=-0.20).[Conclusion]The genetic mechanism of lodging resistance in the F2 population of Yuehesimiao×Xiangyaxiangzhan shows that N2 wall thickness is significantly positively correlated with N2 breaking resistance and is the core trait of stem lodging resistance,which is a quantitative trait controlled by polygenes.Taking N2 wall thickness as the research focus will greatly reduce the complexity of previous research methods for lodging resistance,which clarifies the research goals and directions for future lodging resistance-related researches.

Hybrid rice breeding is an important strategy for enhancing grain yield. Breeding high-performance parental lines and identifying combining abilities is a top priority for hybrid breeding. Yuenongsimiao (YNSM) and its derivative variety Yuehesimiao (YHSM) are elite restorer lines with a high ability of fertility restoration, from which 67 derived hybrid combinations have been authorized to different degrees in more than 110 instances in China. In this study, we found that YNSM and YHSM contained three candidate restorer-of-fertility (Rf) genes, Rf3, Rf4, and Rf5/Rf1a, that might confer their restoration ability. Subsequently, we investigated heterosis and combining ability of YNSM and YHSM using 50 F1 hybrids from a 5 × 10 incomplete diallelic mating design. Our results indicated that hybrid combinations exhibited significant genetic differences, and the additive effects of the parental genes played a preponderant role in the inheritance of observed traits. The metrics of plant height (PH), 1000-grain weight (TGW), panicle length (PL), and the number of spikelets per panicle (NSP) were mainly affected by genetic inheritance with higher heritability. Notably, the general combining ability (GCA) of YHSM exhibited the largest positive effect on the number of grains per panicle (NGP), NSP, PL, and TGW. Thus, YHSM had the largest GCA effect on yield per plant (YPP). In addition, the GCA of YNSM exhibited a positive impact on YPP, mainly due to the critical contribution of seed setting percentage (SSP). Moreover, YNSM and YHSM exhibited negative GCA effects on PH, implying that YNSM and YHSM could effectively enhance plant lodging resistance by reducing the plant height of the derived hybrids. Remarkably, among the hybrids, Yuanxiang A/YNSM (YXA/YNSM), Shen 08S/Yuemeizhan (S08S/YMZ), and Quan 9311A/YHSM (Q9311A/YHSM) represent promising new combinations with a higher specific combining ability (SCA) effect value on YPP with a value more than 3.50. Our research thus highlights the promising application for the rational utilization of YNSM and YHSM in hybrid rice breeding.

In order to promote the process of improving the grain quality of rice, Guangdong Province has started to set up a regional trial of fragrant rice group since 2018. Yuexiang 430 was the first batch of fragrant rice varieties tested and successfully approved by Guangdong Provincial Crop Variety Appraisal Committee. Yuexiang 430 is a thermo-sensitive rice variety with moderate plant-type,strong lodging resistance, high yield and fine quality. The results of the regional test showed that the average yield of Yuexiang 430reached 456.3 kg/667 m2, ranking the first in the regional trail group, which was significantly higher than that of the control variety Meixiangzhan 2. The grain quality of Yuexiang 430 reached the first grade standards of high grain quality rice issued by Chinese Ministry of Agriculture and Rural Affairs, with amylose 16.2%, length-width ratio 3.3 and aroma（2-AP content 675.0～1 030.9 μg/kg）,taste score 84.0～91.0, cooked rice is soft, smooth taste and fragrant, and has won the gold award of the First Conference of Guangdong Rice Industry Development. Yuexiang 430 exhibited strong disease resistance to rice blast in the field tests with leaf blast of grade1.4～3.0 and neck blast of grade 3.0～3.4, and was easily planted and managed for both early and late cropping seasons in Guangdong Province. Yuexiang 430 has performed well in the trials of Yangshan, Huazhou, Xinhui, Maoming and Nanxiong, etc, in Guangdong Province, and has been used for production and processing in many “Guangdong Simiao Rice”industrial parks, and has an excellent prospect of promotion and application.

Upland rice,an ecological type formed by the long-term domestication of rice,is mainly distributed in dry land and hilly land with stable summer rainfall but insufficient irrigation conditions.Currently,the cultivated area of upland rice in the world is about 19 million hm2,accounting for about 12.7%of the total cultivated rice area.With rich resources and a long planting history,upland rice is distributed in different rice growing areas in China.Agriculture is one of the most important sources of greenhouse gas emissions,in which the long-term water layer needs to be established in the process of rice cultivation,accounting for about 16%of the greenhouse gas emissions from agriculture.Many studies have shown that planting upland rice plays an important role in reducing greenhouse gas emissions from paddy fields,which is of great significance for ensuring national food security and achieving national carbon peak and carbon neutrality goals.Due to the relative balance of light,temperature and rainfall in Guangdong Province,double-croping rice is the main planting pattern in each ecological region,and the development of upland rice is relatively lagging.With the decrease of the rural labor force,the shortage of water resources and the continuous occurrence of extreme weather such as high temperature and drought in Guangdong and South China,the market demand for upland rice varieties has increased year by year.This review introduces the drought resistance mechanism,breeding and supporting technologies of upland rice in China and abroad,analyzes the research and planting status of upland rice in Guangdong,and puts forward suggestions on upland rice researches,providing references for molecular breeding and low-carbon cultivation technology of upland rice varieties in Guangdong Province.

白叶枯病是对水稻危害最大的细菌性病害,严重危及我国乃至全球粮食安全.挖掘新的抗病基因是改良水稻对白叶枯病抗病性的重要措施.本研究以广东省及华南稻区主栽的优质抗病水稻品种粤农丝苗为材料,利用抗病品种粤农丝苗和感病品种丽江新团黑谷为亲本构建重组自交系(recombinant inbred lines,RILs)及回交群体,进行接种鉴定及基因定位分析.遗传分析表明:粤农丝苗的抗性由不完全显性的白叶枯病抗病基因控制;重组自交系抗病表型结合重测序结果初定位到一个抗性QTL qBB-11-1,位于11号染色体长臂末端;利用片段重叠群分法将qBB-11-1精细定位在InDel标记P89和P54之间,物理距离约为63 kb,区间内包含6个候选基因,且粤农丝苗中的白叶枯病抗性基因可能是未被报道的新基因.这些研究结果对于主栽品种粤农丝苗的抗性基因挖掘与利用将对华南稻区白叶枯病抗性育种具有重要的代表性意义.

【Objective】Rice seedling transplanting and direct seeding are the most widely used planting methods in Guangdong currently. Exploring the effects of seedling transplanting and direct seeding on rice yield and screening the rice varieties suitable for flooding direct seeding in Guangdong and South China can provide theoretical basis for variety selection and breeding application of direct seeding rice in Guangdong and South China.【Method】Twenty-five rice varieties from Guangdong Province were used as materials to simulate submergence tolerance tests, the growth period, plant height, lodging resistance and yield were measured under two different cultivation modes of seedling transplanting and direct seeding in early and late seasons, and the rice varieties suitable for direct seeding were screened.【Result】The seedling rate of 12 rice varieties, such as Yuexinyinzhan 2, Yuenongsimiao and Yuetaiyouzhan with submergence tolerance reached more than 80%.It was found that the growth period of direct seeding rice was 7-15 d shorter than that of seedling transplanting by analyzing the two cultivation modes of seedling transplanting and direct seeding in early and late seasons. As it showed in the field lodgingresistance phenotype identification, 11 rice varieties had stronger lodging resistance. Yield analysis showed that the yields of direct seeding in early and late seasons were higher than those of seedling transplanting, with an average increase of 0.99 % and 1.25 %, respectively.【Conclusion】Based on the submergence tolerance, lodging resistance and high yield of the tested varieties, 4 varieties including Yuenongsimiao, Yumeizhan, Wushansimiao and Yuteyouzhan were selected to be suitable for direct seeding cultivation pattern in South China.

改良早熟型两系不育系'粤早1S'米质特性,为选育适合华南稻区及长江中下游优质早中稻杂交稻组合奠定基础.本研究以携带低直链淀粉基因Wx的两系不育系材料'RGD-7S'为供体亲本,以早熟型两系不育系'粤早1S'为轮回亲本进行杂交,开展杂交、回交和自交相结合的系谱选育方法与分子标记辅助选择(MAS)技术,贯穿以不育系鉴定、人工气候箱光温反应鉴定、米质测定与室内米饭蒸煮食味品质鉴定等方法.通过2次回交,12次杂交,8年系谱选育,最终获得农艺性状整齐、不育株率100％、含有Wx基因且直链淀粉(干基)含量降低的两系不育系'台早1S',该不育系在广州早造播始历期60 d、晚造播始历期47 d,雄性不育期达140 d以上,不育起点温度为23℃,米质鉴定直链淀粉含量为13.6％.'台早1S'于2017年获农业部农作物新品种权申请号20173673.7,并成功进行成果转化,2018年9月通过广东省技术鉴定.本研究通过分子标记辅助选择技术与系谱选育相结合的方法,有效地降低了'粤早1S'直链淀粉含量,改良了米质特性,选育得到农艺性状优良的优质早熟两系不育系'台早1S',为配制优质早熟两系不育系杂交稻组合,充实华南和长江中下游稻区中早熟优质两系杂交稻市场提供了良好材料的基础.

Rice is one of the food crops with the largest planting area and the highest total output in China, which plays an important role in ensuring national food security. Since the "Green Revolution", China's rice yield per unit area has been greatly improved. However, the lodging problem of rice has long restricted the high and stable yield and excellent quality of rice. A large area of lodging of rice will lead to serious yield loss and rice quality decline. At present, with the continuous improvement of rice yield per unit area, the problem of rice lodging is becoming increasingly prominent, which has been one of the great hidden dangers threatening the normal rice production. Through decades of continuous research, researchers at home and abroad have made great progress in the cause, mechanism, influencing factors, evaluation methods and lodging resistance genetics and breeding of rice. The study summarizes the research progress of rice lodging resistance since the"Green Revolution", combined with the lodging resistance research work experience for many years, comprehensive analyzes the research the origin of rice lodging resistance, clarifies the properties of rice lodging, summarizes the main related factors of rice lodging resistance, and puts forward the relevant countermeasures to raise the capacity of rice lodging resistance. On the basis of the existing research, the main directions of rice lodging resistance breeding, cultivation and molecular mechanism research in the new era are prospected in order to provide references for rice lodging resistance researchers.

Rice quality is a comprehensive quantitative trait greatly influenced by heredity and environment. Here, 11 rice quality traits and Rapid Visco-Analyser (RVA) profiles of 30 indica rice germplasms were detected and analyzed. In addition, we used grain size genes and starch synthesis gene Wx to detect the rice quality genotypes of rice. The results showed different degrees of correlation among rice quality traits. In addition, principal component analysis (PCA) divided rice quality traits into four principal components, and the cumulative contribution rate reached 82.478%. Cluster analysis divided 30 rice varieties into five categories. The first four types had better rice quality. Identification of rice quality genes indicated that most of the genotypes were GS3, GS9, GW5, GW8 and Wx(b), and a few were GW7 and Wx(a). Identifying rice quality characteristics and genotypes of rice varieties may lay a theoretical foundation for promoting the cultivation of new rice varieties, enabling breeders and researchers to develop better rice varieties.

Leaf senescence is one of the most precisely modulated developmental process and affects various agronomic traits of rice. Anti-senescence rice varieties are important for breeding application. However, little is known about the mechanisms underlying the metabolic regulatory process of leaf senescence in rice. In this study, we performed transcriptomic and metabolomic analyses of the flag leaves in Yuenong Simiao (YN) and YB, two indica rice cultivars that differ in terms of their leaf senescence. We found 8524 genes/204 metabolites were differentially expressed/accumulated in YN at 30 days after flowering (DAF) compared to 0 DAF, and 8799 genes/205 metabolites were differentially expressed in YB at 30 DAF compared to 0 DAF. Integrative analyses showed that a set of genes and metabolites involved in flavonoid pathway were significantly enriched. We identified that relative accumulation of PHENYLALANINE AMMONIA-LYASE ( PAL ), CINNAMATE 4-HYDROXYLASE ( C4H ), 4-COUMAROYL-COA LIGASE ( 4CL ), CHALCONE SYNTHASE ( CHS ) and CHALCONE ISOMERASE ( CHI ) in YN30/0 was higher than that in YB30/0. Three flavonoid derivatives, including phloretin, luteolin and eriodictyol, showed lower abundances in YB than in YN at 30 DAF. We further revealed a MYB transcription factor, which is encoded by OsR498G0101613100 gene, could suppress the expression of CHI and CHS . Our results suggested a comprehensive analysis of leaf senescence in a view of transcriptome and metabolome and would contribute to exploring the molecular mechanism of leaf senescence in rice.