Direct-Seeded Rice: Genetic Improvement of Game-Changing Traits for Better Adaption

The sustainability of rice production continues to be a subject of uncertainty and inquiry attributed to shifts in climatic conditions. In light of the impending climate change crisis and the high labor and water costs accompanying it, direct-seeded rice(DSR) is unquestionably one of the most practical solutions. Despite its resource and climate-friendly advantages, early maturing rice faces weed competitiveness and seedling establishment challenges. Resolving these issues is crucial for promoting its wider adoption among farmers, presenting it as a more effective sustainable rice cultivation method globally. Diverse traditional and contemporary breeding methods are employed to mitigate the limitations of the DSR approach, leveraging advanced techniques such as speed breeding and genome editing. Focusing on key traits like mesocotyl length elongation, early seedling vigor, root system architecture, and weed competitiveness holds promise for transformative improvements in DSR adaptation at a broader scale within farming communities. This review aims to summarize how these features contribute to increased crop production in DSR conditions and explore the research efforts focusing on enhancing DSR adaptation through these traits. Emphasizing the pivotal role of these game-changing traits in DSR adaptation, our analysis sheds light on their potential transformative impact and offers valuable insights for advancing DSR practices.

Investigation of GhFAT Genes Related to Seed Oil Content and Fatty Acid Composition in Gossypium hirsutum L.

Fatty Acyl-ACP thioesterase(FAT)is a key enzyme controlling oil biosynthesis in plant seeds.FATs can be divided into two subfamilies,FATA and FATB according to their amino acid sequences and substrate specificity.The Upland cotton genome contains 20 GhFAT genes,amongst which 6 genes were of the GhFATA subfamily and 14 of the GhFATB subfamily.The 20 GhFAT genes are unevenly distributed on 14 chromosomes.The GhFATA genes have 5 or 7 exons and the GhFATB genes have 6 or 7 exons.All GhFAT proteins have the conserved Acyl-ACP_TE domain and PLN02370 super family,the typical characteristics of plant thioesterases.Analyses of the expression level of GhFATs and the compositions of fatty acid in 5-60 days-post-anthesis seeds showed that the ratio of saturated fatty acids to unsaturated fatty acids was consistent with the expression profile of GhFATB12,GhFATB3,and GhFATB10;the ratio of monounsaturated fatty acid to polyunsaturated fatty acids was consistent with the expression profile of GhFATA3.The oil contents of mature cottonseeds were positively correlated with the contents of palmitic acid and linolenic acid as well as seed vigor.These results provide essential information for further exploring the role(s)of the specific GhFATs in determining oil biosynthesis and cottonseed compositions.

Effects of Different Seed Coating Agents on the Quality of"Grey-matter"Hybrid Rice Seeds

[Objectives]This study was conducted to select suitable mixed seed coating agents for improving the quality of"grey-matter"hybrid rice seeds.[Methods]Three different mixed seed coating agents(A,B,C)were used to coat the seeds of two varieties(Taiyou 390 and Zhenliangyou 8612)of hybrid rice with different"grey-matter"content(5%,15%,25%),and the results were investigated and compared.[Results]The combinations of treatment B(seed coating agent A+Linong)and treatment C(Manshijin+seed coating agent A)could significantly improve indexes including seed germination potential,germination rate,seed vigor,seedling height,fibrous roots and fresh weight of the two varieties with a"grey-matter"content greater than 15%,but had no significant effects on main root length,dry weight,leaf number and tiller number,and the effects of treatment B was better than those of treatment C.That is to say,mixed seed coating agent B(seed coating agent A+Linong)was suitable for use as a seed coating agent to improve the quality of"grey-matter"seeds.[Conclusions]This study provides a reference plan for the safe use of mixed seed batches with"grey-matter"deterioration.

硝态氮浓度对冬小麦幼苗根系活力及根际pH值的影响(英文)

[Objective] The aim was to research the effect of concentration of NO-3-N on root vigor and rhizosphere pH of winter wheat seedlings under water culture.[Method]By selecting Hoagland's nutritional solution as cultural medium and winter wheat as material of experiment,on the basis,testing root vigor,nutrient solution NO-3 and change of pH values under the different level of disposal,such as high(containing NO-3-N 15 mmol/L),medium(containing NO-3-N 7.5 mmol/L)and lower(containing NO-3-N 2.5 mmol/L).[Result]The results of this research showed that the effect of different nitrogen level on the wastage of nutrient solution NO-3,the changes of pH values and root vigor is obvious under the hydroponics condition.[Conclusion]Though NO-3 is a safe nitrogen sources when it was supplied to plants too more,it would restrain assimilation on nitrate nitrogen farther,but when it was supplied to plants too little,it would lead to deficiency of NO-3 that plants uptake and decrease of root activity,so it isn't useful to wheat young seedling to absorb nitrogen nutrition.

魅力体育运动 活力国土资源

汉语词典将活力解释为:旺盛的生命力。活力用英语表示为"vigor",意为身体或精神上的力量或能量。活力由三个维度的能量组成,即体力、情绪能量、认知灵敏性。就体力而言,有活力的员工表现为身体健康强壮;就情绪能量而言,有活力的员工通常表现为情绪稳定,积极乐观,关心、同情他人;就认知灵敏性而言,有活力的员工自信、思维敏捷,工作效率高。国土资源部门的干部职工充满了活力,勇于改革、勇于实践、勇于进取、勇创佳绩、勇夺第一,为整个社会经济的发展提供强有力的国土资源保障。本刊从本期开始,开设"活力国土"栏目,展示国土文化建设,展示活力国土人的风采。

军用决策支持系统VIGOR

本文介绍了军用决策支持系统ＶＩＧＯＲ的设计与实现，并讨论了它对军用辅助决策功能的支持。

Advances on Seed Vigor Physiological and Genetic Mechanisms

Seed vigor is a more promising seed quality character reflecting potential seed germination, field emergence and seed storage ability under different conditions than standard germination. Standard germination is influenced by genetic background and environmental effects during seed development and storage conditions. The latest research on physiological mechanism in seed vigor showed that at the late stage of seed development, the development of seed vigor involves some stress-resistant substances including late embryogenesis abundant （LEA） protein, oligosaccharides and abscisic acid （ABA）. Whereas the loss of seed vigor, or seed aging and deterioration, could be attributed to lipid peroxidation, chromosome deformation and genes aberrance, and embryo protein degradation, etc. Seed vigor is a quantitative character controlled by multi-genes. Genetic and quantitative trait locus （QTL） analyses on seed-vigor trait in model plants, such as Arabidopsis and rice, are mostly concentrated on related morphology traits, whereas few physiological traits have been researched. It was concluded that, all of the QTL genetic characteristics of seed vigorincluding QTL quantities, its locus on chromosome, genetic effects, and interaction effects between genetic and environment, differed with plant species and used seed-vigor traits.

Effect of mechanical threshing on damage and vigor of maize seed threshed at different moisture contents

Mechanical threshing used when preparing maize seeds for planting subjects seed to damage and reduces seed quality.The purpose of this study was to assess the effect of mechanical threshing on the quality of maize seed threshed at different moisture contents(MCs).Seeds of dent maize JK968 and flint maize DD2 were threshed at 12,15,18,21,and 24% MC.The damage degree was determined by iodine staining,and seed vigor was assessed by standard germination(SG),cold test germination(CTG),accelerated aging germination(AAG),seedling emergence rate,and seedling root and shoot length.The results showed that the damage percentage increased,and the seed vigor parameters decreased with increasing seed MC during threshing in both cultivars.For obtaining high seed quality,indicated by at least 90,85,and 80% of SG,AAG,and CTG,respectively,JK 968 and DD2 should be threshed at MC lower than 15 and 18%,respectively.Furthermore,the damage mainly occurred in the apical part of seeds,irrespective of the threshing MC in both cultivars.When the embryo was damaged,seedling emergence rates were significantly reduced with great influence on shoot length.Damage to the endosperm resulted in little effect on seedling performance.Flint maize DD2 was more tolerant to mechanical threshing than dent maize JK968.These results provided technical reference for the production and processing of high vigor maize seeds.

Germination and early seedling growth of Pinus densata Mast.provenances

We studied seed germination and early seedling growth of Pinus densata to explore the range of variability within the species and to inform afforestation practices. Phenotypes were evaluated at a forest tree nursery under conditions that support Pinus yunnanensis, one of the presumed parental species of P. densata. Seeds were col- lected from 20 open-pollinated trees within each of eight autochthonous populations representing the natural distri- bution of P. densata in China to assess variation in ger- mination traits and early seedling growth, and to examine the relationships among these traits. Results showed that seeds from all populations germinated and seedlings established successfully. There were significant differences among populations in 13 of 14 traits evaluated. Seed germination and early seedling growth were strongly related to seed size and seed weight. Bigger seeds germi- nated earlier and faster than small seeds, and seedling size was positively correlated with seed size. Some germination traits were strongly and significantly correlated with cli- matic variables associated with the provenance of the studied populations. Based on these observations, we conclude there were large, significant, and biologically important differences among P. densata populations in seed germination and seedling growth traits. The observed variability probably reflects a high degree of adaptive dif- ferentiation among populations that is likely to be relevant for future afforestation.

Selection for high quality pepper seeds by machine vision and classifiers

This research aimed to improve selection of pepper seeds for separating high-quality seeds from low-quality seeds. Past research has shown that seed vigor is significantly related to the seed color and size, thus several physical features were identified as candidate predictors of high seed quality. Image recognition software was used to automate recognition of seed feature quality using 400 kernels of pepper cultivar 101. In addition, binary logistic regression and a neural network were applied to determine models with high predictive value of seed germination. Single-kernel germination tests were conducted to validate the predictive value of the identified features. The best predictors of seed vigor were determined by the highest correlation observed between the physical features and the subsequent fresh weight of seedlings that germinated from the 400 seeds. Correlation analysis showed that fresh weight was significantly positively correlated with eight physical features： three color features （R, a＊, brightness）, width, length, projected area, and single-kernel density, and weight. In contrast, fresh weight significantly negatively correlated with the feature of hue. In analyses of two of the highest correlating single features,＇ germination percentage increased from 59.3 to 71.8% when a＊〉3, and selection rate peaked at 57.8%. Germination percentage increased from 59.3 to 79.4%, and the selection rate reached 76.8%, when single-kernel weight 〉0.0064 g. The most effective model was based on a multilayer perceptron （MLP） neural network, consisting of 15 physical traits as variables, and a stability calculated as 99.4%. Germination percentage in a calibration set of seeds was 79.1% and the selection rate was 90.0%. These results indicated that the model was effective in predicting seed germination based on physical features and could be used as a guide for quality control in seed selection. Automated systems based on machine vision and model classifiers can contribute to reducing the costs and labor required in the selection of pepper seeds.

Identification of QTL and candidate genes involved in early seedling growth in rice via high-density genetic mapping and RNA-seq

Early seedling vigor(ESV)is a major breeding target in rice,especially under direct seeding.To identify quantitative trait locus(QTL)affecting ESV,a recombinant inbred line population derived from a cross between 02428 and YZX,two cultivars differing in vigor during early seedling growth,was used for QTL analysis.Nine traits associated with ESV were examined using a high-density map.Of 16 additive loci identified,three were detected in two generations and thus considered stable.Four epistatic interactions were detected,one of which was repeated in two generations.Further analysis of the pyramiding effect of the three stable QTL showed that the phenotypic value could be effectively improved with an increasing number of QTL.These results were combined with results from our previous QTL analysis of the germination index.The lines G58 and G182 combined all the favourable alleles of all three stable QTL for ESV and three QTL for germination speed.These two lines showed rapid germination and strong ESV.A total of 37 candidate differentially expressed genes were obtained from the regions of the three stable QTL by analysis of the dynamic transcriptomic expression profile during the seedling growth period of the two parents.The QTL are targets for ESV breeding and the candidate genes await functional validation.This study provides a theoretical basis and a genetic resource for the breeding of directseeded rice.

Comparative QTL analysis of maize seed artificial aging between an immortalized F_2 population and its corresponding RILs

Seed aging decreases the quality and vigor of crop seeds,thereby causing substantial agricultural and economic losses in crops.To identify genetic differences in seed aging between homozygotes and heterozygotes in maize,the seeds of a set of recombinant inbred lines(RILs) and an immortalized F_2(IF_2) population were subjected to artificial aging treatments for 0,2,3,and 4 days under 45℃ and 85%relative humidity and seed vigor was then evaluated in a field experiment.Seed vigor of all entries tested decreased sharply with longer aging treatment and seed vigor decreased more slowly in heterozygotes than in homozygotes.Forty-nine QTL were detected for four measured seed vigor traits in the RIL(28QTL) and IF_2(21 QTL) populations.Only one QTL,qGP5,was detected in both populations,indicating that the genes involved in anti-aging mechanisms differed between inbred lines and hybrids.Several QTL were identified to be responsible for multiple seed vigor traits simultaneously in the RIL and IF_2 populations under artificial aging conditions.These QTL may include major genes for seed vigor or seed aging.QTL qVI4 b and qGE3 a detected in the RIL population coincided with genes ZmLOX1 and ZmPLD1 in the same respective chromosomal regions.These QTL would be useful for screening for anti-aging genes in maize breeding.

Improving the assessment method of seed vigor in Cunninghamia lanceolata and Pinus massoniana based on oxygen sensing technology

Oxygen sensing technology was employed to study the rapid methods for seed vigor assessment of Chinese fir （Cunninghamia lanceolata） and Masson pine （Pinus massoniana）. Firstly, seeds of five lots were performed using accelerated aging （AA） into three vigor levels. Then, four oxygen sensing indices, including increased metabolism time （IMT）, oxygen metabolism rate （OMR）, critical oxygen pressure （COP）, relative germination time （RGT） and the control indiees such as labora- tory germination indices, dehydrogenase activity （DA）, and electrical conductivity （EC） were analyzed by the tests of 15 samples. The results of correlation analysis between these indices and field emergence per- formances based on two-year and two-spot data showed that RGT and OMR should be indicated as the optimal oxygen sensing indices to rap- idly and automatically evaluate seed vigor of Chinese fir and Masson pine, respectively. On the basis, one-variable linear regression equations were built to forecast their field emergence performances by the two oxygen sensing indices.

Combining Ability and Genetic Effects of Germination Traits of Brassica napus L.Under Waterlogging Stress Condition

Cross combinations from six rapeseed cultivars and lines were evaluated under waterlogging stress condition in order to understand the genetic mechanism of waterlogging tolerance of Brassica napus L.and provide reasonable improvement programs.There were six germination traits investigated on combining ability and heritability using complete diallel crossing method designed for 30 combinations from those six cultivars and lines.The traits included relative root length,stem length,fresh weight per plant,survival rate,electrical conductivity,and vigor index.After flooding treatment,the six traits of parents and F1 were analyzed.The general combining ability（GCA） and special combining ability（SCA） of germination traits were analyzed using Griffing I method.Among 30 cross combinations,the GCA was significantly different among six waterlogging resistance traits.The SCA of these traits was significantly different except the SCA of electrical conductivity.As a representative trait of waterlogging tolerance in rapeseed,relative vigor index had the highest narrow heritability and relatively low broad heritability.The cultivars Zhongshuang 9 and P79 had higher tolerance potential to waterlogging stress.It can be concluded that combining ability and genetic effects of relative vigor index during germination stage could be used to identify the waterlogging tolerance of rapeseed in breeding program.

Effects of Pb Pollution on Seed Vigor of Three Rice Cultivars

An experiment was conducted to study the effects of different Pb concentrations on rice seed germination and seedling growth in three cultivars （Jiayu 293, Jiayu 948 and Xieyou 963）. The method of qualitative traits combining with quantitative traits by orthogonal polynomials was applied to analyze rice seed vigor by regression model. The seeds from different rice cultivars had different sensitivity to Pb poison. In the Pb concentration of 100-700 mg/L, Pb significantly decreased root length and shoot height, and the degree of the restraint would aggravate with the increasing of Pb concentration. However, Pb did not reduce root dry weight and shoot dry weight, which indicated that different physiological characteristics had different sensitive reactions to Pb. The predicting equations of regression were developed, which could be used to predict the effects of different Pb concentrations on rice seed vigor.

Hyperspectral imaging technology to detect the vigor of thermal-damaged Quercus variabilis seeds

This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration(0,2,5,and 10 h).After obtaining hyperspectral images with a 370–1042 nm hyperspectral imager that included visible and near infrared light,germination was tested to confirm estimates.The Savitzky–Golay(SG)second derivative was used to preprocess the spectrum to reduce any noise impact.The successive projections algorithm(SPA),principal component analysis,and local linear embedding algorithm were used to extract the characteristic spectral bands related to seed vigor.Finally,a model for seed vigor classifi-cation of Q.variabili s based on partial least squares support vector machine(LS-SVM)with different spectral data sets was developed.The results show that the spectrum after SG second derivative preprocessing was better for developing the model,and SPA performed the best among the three feature band selection methods.The combination SG second derivative-LS-SVM provided the best classification model for Q.variabilis seed vigor,with the prediction set reaching 98.81%.This study provides an important basis for rapid and nondestructive assessment of the vigor of heat-damaged seeds using hyperspectral imaging techniques.

Physiological Mechanism of Nitrogen Mediating Cotton (<i>Gossypium hirsutum</i>L.) Seedlings Growth under Water-Stress Conditions

The objective of this investigation was to study the effects of nitrogen on tolerance to water-stress in cotton (Gossypium hirsutum L.) seedlings. Growth chamber studies with pots of washed sand were carried out in Fayetteville, USA, and Nanjing, Chinawith three water conditions (well-watered, drought-stressed, and waterlogging), and three nitrogen rates, low nitrogen (16 mM, approximately 224 mg N·l–1 water), medium nitrogen (24 mM, approximately 448 mg N·l–1 water) and high nitrogen (32 mM, approximately 672 mg N·l–1 water), respectively. The results showed that water-stress treatments reduced plant biomass, C/N ratio, root vigor and leaf photosynthesis (Pn). The plant response to water-stress resistance was affected by nitrogen, and was correlated with the activities of antioxidant enzymes. The changes of anti-oxidant enzymes was the highest in the low nitrogen rate in the drought-stressed and waterlogged cotton seedlings. Malondialdehyde (MDA) content increased significantly in the water-stress treatments, and was the lowest in the low nitrogen rate. There was a significant reduction of N accumulation under water stress. Low-nitrogen treatmentincreased C accumulation, while high-nitrogen treatment decreased N accumulation. Root vigor was decreased by water stress, and was highest in the low-nitrogen rate. After terminating the water stress, N application promoted root vigor, especially in waterlogged seedlings. The trends of Pn weresimilarto that of root vigor. These results suggested that low N application may contribute to cotton drought tolerance by enhancing the activity of antioxidant enzymes and conse-quently decreasing lipid peroxidation, and enhancing root vigor. However, higher N should be applied to waterlog- ging-stressed cotton seedlings after terminating waterlogging.

Changes in Nutrient-Homeostasis and Reserves Metabolism During Rice Seed Priming:Consequences for Seedling Emergence and Growth

In this study influence of different seed priming treatments on the nutrient-homeostasis and reserve metabolism during seedling emergence and growth of rice were determined. Seed priming treatments included pre-germination, hydropriming for 48 h, osmohardening with KCl and CaCl2, ascorbate priming and hardening. All treatments shortened the emergence time and enhanced the energy and index of seedling emergence. Seedlings from primed seeds had greater length, number of roots and fresh and dry mass than control. Among the treatments, CaCl2, ascorbate and KCl proved better in enhancing emergence and seedling growth. Seed priming changed the pattern of N and Ca^2＋ homeostasis both of the seeds and seedlings, which were associated to enhancing s-amylase activity and reducing sugars content. Positive correlations of seedling attributes with nutrient content suggested that as a result of seed priming, most of N and Ca^2＋ were partitioned to embryo, which enhanced seedling emergence and subsequent growth of rice seedlings.

Nucleus Transfer Efficiency of Ear Fibroblast Cells Isolated from Bama Miniature Pigs at Various Ages

Summary： Somatic cell nucleus transfer （SCNT） has been considered the most effective method for conserving endangered animals and expanding the quantity of adult animal models. Bama miniature pigs are genetically stable and share similar biological features to humans. These pigs have been used to establish animal models for human diseases, and for many other applications. However, there is a pan- city of studies on the effect of ear fibroblasts derived from different age of adult Bama miniature pigs on nucleus transfer （NT）. The present study examined the NT efficiency of ear fibroblasts from fetal, new- born, 1-, 2-, 4-, 6-, 12-month-old miniature pigs by using trypan blue staining, flow cytometry and NT technique, etc., and the cell biological function and SCNT efficiency were compared between groups. The results showed that ear fibroblasts grew well after passage in each group. Spindle-shaped cells ini- tially predominated, and gradually declined with increase of culture time and replaced by polygonal cells. Irregular cell growth occurred in the 2-month-old group and the elder groups. The growth curves of the ear fibroblasts were ＂S-shaped＂ in different age groups. The cell proliferation of postnatal ear fi- broblasts, especially those from 2-, 4-, 6-, 12-month-old miniature pigs was significantly different from that of fetus ear fibroblasts （P〈0.05 or P〈0.01）. Two-month- and 4-month-old ear fibroblasts had a sig- nificantly higher proportion of G1 stage cells （85% to 91%） than those at 6 and 12 months （66% to 74%, P〈0.01）. The blastocyst rate of reconstructed embryos originating from newborn, 1-, 2-, 4-month-old donor pigs was 6.06% to 7.69% with no significant difference from that in fetus fibroblast group （8.06%）. It was concluded that 〈4-month-old adult Bama miniature pigs represent a better donor cell resource than elder pigs.

Effects of submergence in water on seed germination and vigor of the Copaifera lucens(Fabaceae) seedlings

We analyzed the tolerance of Copaifera lucens seeds to sub- mersion in water to assess the use of this species for direct seeding in riparian forest restoration programs. Seeds were submerged in water for 2, 4, 8, 16 and 32 days or not submerged （control = 0 days of submer- gence）. For the control and at the end of each period of submersion, germination and seedling vigor tests were carried out. For germination tests, seeds were sown in plastic pots containing sand and kept in labora- tory conditions. The percentage of seed germination, the germination rate and the average germination time were analyzed. For seedlings, total biomass, leaf area, leaf mass per area and leaf area ratio were analyzed. Submersion time drastically affected the dissolved oxygen content and seed germination. Between 4 and 8 days of submersion there was a de- crease from 83.8% to 15.6% in the germination percentage. No seed germination occurred after 16 days of submersion. Although there was a significant decrease in the percentage of seed germination between 4 and 8 days of submersion, seedling vigor was not affected. Seeds of this species were partially tolerant to submersion in water, suggesting that C. lucens is a promising species for direct seeding in riparian forest restora- tion projects.