Abstract:To advance the breeding of new sweet cherry varieties and enhance the conservation and utilization of germplasm resources， this study employed correlation analysis， principal component analysis， and cluster analysis to evaluate and investigate 12 external and 4 internal quality indicators of fruits in 35 sweet cherry varieties （lines）. The results revealed that the predominant fruit shape was oblate， with a flat fruit and a concave fruit apex. The Simpson indices for these three descriptive traits were 0.700， 0.561， and 0.573， respectively， indicating a rich diversity. Among the 13 quantitative traits， the coefficient of variation （CV） was lowest for the edible rate （3.35%）， and highest for the abnormal fruit rate （95.00%）. High CVs were also observed for fruit stalk separation force （30.82%）， solid acid ratio （28.05%）， flesh weight （26.65%）， and fresh core weight （26.03%）， reflecting substantial genetic differentiation. Single fruit weight was significantly positively correlated with fruit flesh weight and edible rate； While the solid acid ratio was significantly positively correlated with fruit juice pH and negatively correlated with titratable acid content. Cluster analysis categorized the sweet cherry cultivars into four distinct groups based on fruit quality attributes. Group A exhibited the lowest average titratable acid content and the highest average edible rate； Group B showed the highest average fruit stalk thickness and hardness， with lowest average total soluble solid content and pH value； Group C， which include only one variety， Black Pearl， had the largest single fruit weight and abnormal fruit rate with smallest fruit stalk separation force and group D presented the highest average total soluble solid content and pH value， along with lowest average abnormal fruit rate and edible rate. Collectively， 'Regina'， 'SJ-54'， and 'Royal Lee' with high composite scores， were identified as superior parents with potential application in sweet cherry breeding programs.

Abstract:In order to evaluate the variations among different grape varieties with distinct berry shapes， 666 grape germplasms were planted in the National Grape Germplasm Repository （Zhengzhou）， and the berry shape associated characters were measured. Comprehensive evaluation and statistical analysis were carried out on the phenotypic variation of berry vertical and transverse diameter， individual berry weight and seed number， and the expression levels of genes that related to berry shape were analyzed as well. The analysis showed that， the berry shapes of cultivated varieties could be categorized into 11 types， namely round，obloid，oval shape，nearly round，long oval，broad lipsoid，obovoid，ovoid，curved shape，chicken heart shape and waist shape. In contrast， the berry shape of wild germplasms was mainly round， only a few were identified with broad lipsoid and chicken heart shaped in the species Vitis davidii. The germplasms of V. vinifera L. showed richer diversity on the berry shapes than the V. vinifera × V. labrusca hybrids. Wine grapes are mainly round and oval， with fewer types of the berry shape than table grapes. Statistical analysis of individual berry weight across different berry shapes revealed that the average individual berry weight of round （3.9 g） and chicken heart grape （3.4 g） was lower， and that of oval shape （6.3 g） and obovoid grape （7.1 g） was higher. The individual berry weight was found positively correlated with the vertical diameter and the transverse diameter of the berry， and the regression equations differed across types of berry shape. The number of seeds in single berry ranged from 0 to 6. Among these， grape varieties are most commonly with 2 seeds， followed by 3 seeds. Varieties with 5 or 6 seeds were rare and were predominantly found in round grapes. Quantitative reverse-transcript PCR （qRT-PCR） analysis was performed on those candidate genes of grape berry shape， the expression level of gene VvFUL1^A and VvSUN showed significant differences between types of elongated shape （eg. oval and curved） and round shape （eg. broad lipsoid and nearly round）， which might be important regulators of the grape berry shape. This study provides references for future grape breeding and fruit shape research.

Abstract:In this paper， seven characteristics of fruit texture in 202 jujube were measured and evaluated by coefficient of variation， index of diversity， correlation analysis and cluster analysis. The variation coefficient and diversity index showed that the variation coefficient of pulp moisture content and pulp density was less than 10%， and the variation coefficient of the other 5 traits were larger， ranging from 15.51% to 33.03%. The diversity index ranged from 1.96 to 2.10， indicating that the tested germplasms were rich in diversity. The correlation analysis showed that there were extremely significant correlation between pericarp puncture strength， mean pulp firmness， pulp compactness and pericarpto pulp brittleness. Two principal components were extracted by principal component analysis， and the cumulative contribution rate was 63.17%. Combined with principal component analysis and stepwise regression analysis， the results showed that mean pulp firmness， pericarp puncture strength， pulp compactness and pericarpto pulp brittleness were the main factors of fruit quality land character variation， and could be used as the guiding key traits for germplasm resource identification. The comprehensive value H of jujube fruit quality was calculated by the variance contribution rate of principal components. According to the H value， 202 jujube germplasm were divided into crisp and juicy type （H value， -2.62--0.41）， dense and juicy type （H value， -0.33--0.77） and dense and low-juice type （H value， 0.86-4.81） by systematic clustering method. The results provided an important basis for the identification， evaluation， development and utilization of the texture characters of jujube.

Abstract:To explore the genetic diversity of key agronomic traits of domestic and imported sugar beet germplasm resources， a genetic diversity analysis of 12 agronomic traits in 679 accessions was conducted in this study. The results showed that the nine descriptive agronomic traits exhibited genetic diversity ranging from 0.5876 to 1.4250. The coefficient of variation at the three numerical agronomic traits ranged from 33.96% to 50.33%. The germplasm resources with the most significant range differences in root yield and sucrose content were collected from Inner Mongolia， China. These samples with the highest coefficients of variation in root yield were collected from SES Vander Have， and these samples with the highest coefficients of variation in sucrose content were imported from France. The introduced material from Britain Ryan Company showed the highest coefficient of variation and range in sugar yield. The cluster analysis categorized the 679 materials into four clusters： Group Ⅰ mainly showed oblique standing margin shape of the leaf， Group Ⅱ had higher sucrose content， Group Ⅲ had the highest sugar yield， and Group Ⅵ mainly showed the economic type of low yield and low sugar type. Following the identification and comprehensive evaluation of the germplasm resources， a total of 6 super-high-sugar materials， 2 high-sugar materials， 138 high-yield materials， 39 standard materials were identified. One high-yield and high-sugar material， three standard-biased high-yield materials， three standard-biased high-sugar materials， and 223 low-yield and low-sugar materials were identified.

Abstract:Using 213 samples of Gossypium barbadense L. as material， four floral traits in three environmental locations （Korla in 2022， Awati County in 2022， and Awati County in 2023） and 41 characters （26 quantitative traits and 15 quality traits） in different growth stages of Gossypium barbadense L. in 2023 environmental locations were determined. Genetic diversity analysis， principal component analysis， correlation analysis， cluster analysis， multiple regression analysis and comprehensive value evaluation were used to evaluate the germplasm resources of 213 Gossypium barbadense L.. These four floral traits were highly susceptible to environment influences， with the anther being particularly sensitive to high-temperature stress. The genetic diversity index of the 41 traits ranged from 0.030 to 2.139， and the variation coefficient of 26 quantitative traits ranged from 2.70% to 30.83%， indicating that the relatively rich genetic diversity. Nine principal components were extracted from the 26 quantitative traits， with a cumulative contribution rate of 74.969%， which were divided into yield component factors， plant growth factors， and plant pollination factors based on their attributes. Multiple regression analysis indicated that the correlation between the quantitative traits used in the test， if compared to pollen viability and the rate of boll shedding was not significant. Using 26 quantitative traits for cluster analysis， 213 resources can be divided into 5 categories：16 high-yield genotypes with excellent overall characteristics， 122 genotypes with excellent floral traits characterized by large flower leaves， 44 materials with commendable fiber quality， 29 genotypes with prominent vegetative organs， and two genotypes with higher pollen activity. Based on the clustering of two high temperature tolerance traits （pollen viability and boll shedding rate）， they were divided into three groups： 102 genotypes with high pollen viability and low boll shedding rate， 63 genotypes with medium pollen viability and 48 genotypes with low pollen viability and high boll shedding rate. There were seven genotypes in the intersection of the two optimal clustering groups. These results provided a theoretical basis for future exploration and germplasm innovation of Gossypium barbadense L..

Abstract:Variations in environmental conditions across different barley-producing regions and the selection targets for barley breeding have led to divergence of the brewing quality in different varieties. In this study， we conducted a comprehensive analysis of the brewing quality， including grain and malt quality traits， for 44 barley varieties that were bred from North America， Europe， and Australia， along with commonly grown barley varieties in China. This research has found that， the major varieties in various domestic regions have their malt quality comparable to foreign varieties differentially. For instance， the variety Longpimai 14 and Longpimai 18 from Northeast China are comparable to the imported European malting varieties. The Supi series from South region and the Ganpi series from Northwest China are comparable to the imported Australian malting varieties. The variety Zhongpimai 1 and Mengpi 3 from North China are comparable to the imported North American varieties. Compared with Chinese malting barley， the foreign varieties are mainly with lower content of β-glucan and higher of the extract. Moreover， the imported malting barley that grown in China showed their quality characters different from those grown in the original areas， as the malt diastatic power， kolbach index and β-glucan content can be affected significantly by the environment. However， most varieties from North American showed better adaptability to the growing conditions in China， without significant change on the malt quality characters in comparing with those grown at their original regions. The malt quality characters， including diastatic power and extract yield， are significantly correlated with the contents of protein， starch， and amylopectin in the grain. Given the measurement of grain quality characters are easier to handle， the grain protein， starch， and amylopectin contents can serve as initial targets for malting barley breeding. This study provided reference of malting barley varieties and guidance for the future selections of malting barley breeding in different domestic regions. It has significant meaning in improving the breeding efficiency and production of domestic malting barley.

Abstract:Soil salinization and alkalization reduce the usability of arable land and impair crop production. Identifying and selecting maize germplasm showing salt-tolerant is of significant importance in the reclamation and utilization of saline-alkali land. To determine the optimal NaCl concentration for screening salt tolerance in maize seedlings， 16 representative inbred lines were treated with 0 （control）， 100， 150， 200， 250， and 300 mmol/L NaCl solutions for seven days. Six indicators， including shoot height， root length， shoot fresh weight， root fresh weight， shoot dry weight and root dry weight， were measured， along with recording the seedling conditions. The results showed that after seven days of salt treatment， significant differences were observed in all indices under 150 mmol/L compared with the control， and the coefficient of variation was greater than at other salt concentrations. Therefore， 150 mmol/L was identified as the optimal concentration for salt tolerance identification in maize inbred lines， and a salt tolerance identification technology was developed. Using this technology， 76 maize inbred lines were analyzed， and a comprehensive salt tolerance evaluation index （D） was calculated using the weighted subordinate function method and cluster analysis. The 76 lines were categorized into four groups： high salt tolerance， salt tolerance， salt sensitivity， and high salt susceptibility. Among them， the inbred lines Ming71， Zhong106， Si-287， and 8112 showed the strongest salt tolerance， serving as valuable resources for salt tolerance maize breeding. The salt tolerance coefficient of the fresh weight of the above-ground tissues showed the highest correction with the D value and could be used as the primary indicator for evaluating salt tolerance in maize inbred lines during the seedling stage.

Abstract:Self-incompatibility in Cruciferous crop such as ornamental kale （Brassica oleracea var. acephala）， is a critical reproductive barrier governed primarily by the multiple alleles at the S loci. Ornamental kale is a typical self-incompatibility member of this family. In this study， we constructed the fingerprint map of 20 inbred lines of ornamental kale using 20 pairs of SSR primers， identified a total of 65 allelic variations， averaging 3.25 variations per primer pair. The unweighted pair group method with arithmetic mean （UPGMA） clustered these into three district genetic groups： OK1， OK2， and OK3. Group OK1 is characterized by wrinkled， wavy leaves， with red and purple as the dominant colors. In contrast， group OK2 features smooth leaves that are either wavy or lobed， with white outer leaves. Group OK3 also presents smooth leaves， which may be wavy or lobed， with red and purple as the primary colors. Through the analysis of specific primers in the kinase region of SRK gene， nine SRK haplotypes were identified in these inbred lines including eight class I SRK haplotypes （SRK7， SRK13， SRK14， SRK16， SRK23， SRK36， SRK45， and SRK51） and one class II SRK haplotype （SRK15）. The SRK15 haplotype was predominant in the group OK1 （50%）， followed by the SRK23 haplotype （20%）. In group OK2， the SRK15 and SRK16 haplotype were both major （at 40% each）. In group OK3， the SRK23 was predominant （40%）. Further analysis of self-incompatible indices confirmed compatibility among inbred lines from the same or different genetic groups， emphasizing the importance of considering both genetic groups and SRK haplotypes in hybrid development.

Abstract:Cowpea is one of the most important legume crops worldwide， serving not only as an important coarse cereal but also as a traditional vegetable in China. Rust is one of the three major diseases in cowpea， and developing rust resistance cultivars is the most cost-effective strategy in disease control. Exploring the resistant germplasm and elucidating the genetic basis of rust resistance is the key and prerequisite for cowpea rust resistance breeding. In the current study， 215 cowpea landraces were examined for rust resistance and 40 accessions showing resistance to rust were identified. Through resequencing the 215 accessions， 3880169 high-quality SNPs and 469398 high-quality InDels were found. These accessions were divided into four subgroups through population structural analysis， and the subgroup division was highly related to pod length and pod type. Total of 10 genomic regions， which significantly associated with rust resistance and distributed on seven chromosomes， were detected by GWAS. Haplotype analysis based on the associated SNPs showed that their alleles were highly correlated to rust resistance. The ratio of resistance accessions increased significantly， when pyramiding increasing number of favored alleles. Ten candidate genes were identified， including BTB/POZ domain-containing protein， LRR receptor-like serine/threonine-protein kinase， ethylene-responsive transcription factor and alternative oxidase genes. These results will provide the theoretical guidance and gene resources for molecular breeding of rust resistance in cowpea.

Abstract:Kernel-related traits， including kernel length， kernel width， and hundred kernel weight， are pivotal factors in determining maize yield. In this study， a recombinant inbred line （RIL） population derived from the maize inbred lines B73 and CML277 was utilized as the experimental material. Based on the high-precision genetic maps constructed through genotyping-by-sequencing （GBS） technology， nine kernel-related quantitative trait loci （QTL） were identified. The major locus qKW2.04 was precisely located on chromosome 2 using the inclusive composite interval mapping （ICIM） method， explaining 20.34% and 15.84% of the phenotypic variation on grain width and 100-grain weight， respectively. In addition， an F₂ segregating population was developed using the recurrent parent B73 and its introgression line （NIL-1041A） to further delimit qKW2.04. This locus was found with contribution due to two tightly linked kernel width major QTL， designated as qKW2.04-1 and qKW2.04-2， which were located in the marker intervals InDel23.32~umc1555 and InDel47.09~InDel57.06， explaining 22.45% and 12.22% of the phenotypic variation， respectively. The favorable allelic variations for both QTLs were contributed by CML277. Through the selection of recombinant individuals within the target region， qKW2.04-1 was finely positioned between molecular markers InDel26.76~InDel27.86 within a 1.1 Mb interval. This study provides new clues for elucidating the genetic basis of kernel-related traits and gene resources for high-yield molecular breeding in maize.

Abstract:Leaves are the main organs for photosynthesis in rice （Oryza sativa L.）， and leaf morphology affects the photosynthetic efficiency of rice plants. Identification of genes that control leaf curling and revealing their genetic mechanisms， could provide genetic resources for optimizing the architecture of rice varieties with moderately curled leaves. In this study， the spontaneous rolled leaf mutant rl76 was measured on their agronomic traits， content of leaf cellulose and chlorophyll， histomorphological observation was carried out as well. In addition， the rice GSR40K chip was applied to map the mutant gene rl76. At the seedling stage， there was no significant difference between the mutant rl76 and the wild type on their leaf rolling severity， both of which showed slightly rolled leaves； through the tillering to the maturity stages， the leaves of rl76 severely rolled into shallot-like shape and erect， while the leaves of wild type were flat and slightly drooping. Comparing with wild type， the leaf rolling index of rl76 increased significantly， while the plant height and effective tiller number decreased significantly， there was no significant difference on leaf width， flag leaf length and panicle length. The chlorophyll content in leaves of rl76 was significantly higher than that of the wild type， the carotenoid content did not significantly vary； nevertheless， the content of cellulose and lignin were lower in rl76 than those in the wild type. The leaf histomophology was observed by paraffin sectioning， in the leaves of rl76 mutant， the two air cavities disappeared， the development of the sclerenchymatous cells on the abaxial surface was defective， and the area and number of the bulliform cells decreased. Genetic analysis showed that the rolled leaf was determined by a single gene inheritance pattern with incomplete dominant. By use of the rice GSR40K chip， the mutant gene rl76 was preliminarily mapped within the region of 12.179-16.436 Mb on chromosome 9. With 949 plants showing severely rolled leaf in an F₂ population， the gene rl76 was further fine mapped within the chromosomal segment delimiting by the SSR markers T5904-7 and T5904-9， corresponding to a physical distance of 30.26 Kb. It contains three annotation genes within this chromosomal segment， among which the gene LOC_Os09g23200 encoding SHALLOT-LIKE 1 （SLL1） has been reported， it determines leaf curling by regulating the development of leaf distal surface cells. Therefore it is speculated that the rolled leaf in the mutant rl76 may be regulated by the gene SLL1. In summary， the rolling leaf in the rl76 mutant was resulted from abnormal development of the bulliform cells and abaxial sclerenchymatous cells that were regulated by a single incompletely dominant gene on chromosome 9.

Abstract:Cell wall invertase （CWIN） is an enzyme that catalyzes sucrose hydrolysis to glucose and fructose， and plays an important role in plant growth and development. To explore the function of GmCWINs in plant architecture， particular in plant height and branch number， GmCWIN3， a member of GmCWINs family was cloned in our study. The sequence analysis results showed that the total CDS length of GmCWIN3 gene was 1728 bp and it encoded 575 amino acids.The secondary structure of GmCWIN3 protein exhibited that the irregular coil structure accounted for the largest proportion （48.17%）， and the tertiary structure of the protein revealed that GmCWIN3 encoded a cell wall invertase. Except for several photo-responsive cis-acting elements， some elements associated with the process of growth and development were also found in the promoter region of GmCWIN3， such as auxin responsive element， gibberellin responsive element and circadian rhythm element， etc. Further， through the assay of exogenous spraying different hormones， it was found that GmCWIN3 gene could rapidly respond to the induction of auxin and gibberellin in the initial reaction period. The GmCWIN3 gene overexpression vector was constructed and the transgenic GmCWIN3 Arabidopsis plants were obtained. The cell wall invertase activity and sucrose content of the transgenic Arabidopsis and wild type plants were measured. The results showed that the cell wall invertase activity of transgenic plants was significantly higher than that in the wild type plants， and the sucrose content was significantly decreased. Additionally， the phenotype identification exhibited that the plant height and branch number of the transgenic plants were significantly increased compared with the wild type plants. In summary， this study speculated that GmCWIN3 gene may be involved in the development of regulating soybean plant height and branch number mediated by hormones signaling process through the regulation of sucrose hydrolysis. Our study laid a foundation for further exploring the molecular mechanism of GmCWIN3 in regulating soybean plant architecture related traits.

Abstract:In the previous study， a salt tolerance related gene FtGST2 （FtPinG0707941400.01） in tartary buckwheat was identified through the whole genome association analysis. The homologous alignment and conserved sequence analysis revealed that the gene belongs to the tetrachlorohydroquinone dehalogenase subfamily of glutathione-S-transferases. We cloned the FtGST2 gene from the cultivar ‘Zhongku-3’， and identified 34 responsive elements including 2 abscisic acid responsive elements and 6 methyl jasmonate responsive elements， in the 2000 bp upstream promoter sequence. Abscisic acid and jasmonic acid are important stimuli for regulating salt stress pathways in plants. Through analyzing the expression levels of FtGST2 in different organs of tartary buckwheat and the differences in expression levels under different concentrations of NaCl treatment， the highest transcripts of FtGST2 were detected in roots， and also under 100 mmol/L NaCl treatment. In addition， we over-expressed FtGST2 in Arabidopsis thaliana and hairy roots， and detected the seed germination rate， main root length， fresh weight， and physiological indicators. The germination rate and root length of Arabidopsis thaliana overexpressing FtGST2 under salt treatment were higher than those of wild-type. The fresh weight of hairy roots overexpressing FtGST2 under salt treatment was significantly higher than that of the control group A4 hairy roots. After testing the four physiological indicators of SOD， POD， CAT， and MDA in hairy roots， it was found that overexpression of FtGST2 gene can effectively improve the salt tolerance of tartary buckwheat hairy root overexpression strains. Collectively， these experiments provided preliminary evidence on the salt resistance function of the FtGST2 gene， laying a certain foundation for the breeding of salt tolerant tartary buckwheat varieties in the future.

Abstract:Auxin response factors （ARFs） are a family of transcription factors that play an important role in flower development through responding to auxin signaling. However， their importance in flower development remains elucidated in sunflower. In this study， 39 ARF family members were identified in sunflower through transcriptome data analysis， and they were categorized into five subfamilies. These members shared similar gene structures， conserved domains and functional motifs. The tissue specific expression pattern analysis showed that 20 ARFs are likely involved in flower development regulation. Through analyzing the transcriptional profiles at various stages during flower development between WT， and the cb1 （crazy broccoli 1） mutant， which exhibits defects in meristem determinacy and floral organ differentiation， five ARF genes （gene33195， gene34899， gene58924， gene2145 and gene16681） showed significant expression changes during flower development. These genes were found to be highly expressed from St2 to St4 in WT but barely expressed in later stages. Their expression was up-regulated in cb1 mutant， corresponding to the peak level at early stages of flower development in WT. Another ARF gene， gene70445 presented higher expressing levels during whole flower development in cb1 mutants than WT plants. We also found that the promoter regions of these six ARF genes contained cis-acting elements recognized by AP2/ERF， MIKC_MADS and LFY， suggesting that they might be regulated by AP2/ERF， MIKC_MADS and LFY family genes during meristem transformation and floral organogenesis. The obtained results could provide important clue for further exploring the biological function and molecular regulatory mechanisms of ARF genes in flower development of sunflower， becoming valuable in future sunflower varieties breeding.

Abstract:The genus Rubus have significant economic value， with southwest China considered as a key distribution center for these species. However， the status of wild Rubus resources in this region remains largely unexplored. In this study， the Rubus resources in southwest China were investigated by field studies， specimen examination and literature review. Additionally， the study preliminarily addressed the collection， preservation and medicinal potential of Rubus resources in southwest China. The results showed that there were 142 Rubus species and 69 varieties in southwest China， representing 68.27% of the total Rubus species found in China， among which 47 species were endemic and 40 varieties. The region boasts 8 herbaceous species and 2 varieties， as well as 134 shrub species and 67 varieties. The fruits predominantly exhibit colors as yellow， red， or black. They are composed of small drupes that accumulate on the flower bed， creating a clustered fruit structure. These fruits are typically either pulpy or dry， and are mostly nearly spherical or spherical in shape， with a diameter of approximately 1 cm.There were 22 species and one variety with medicinal value， while five species are suitable for use as breeding materials or for introduction and domestication in the high altitude area of northwest Yunnan. These Rubus resources are found across a wide range of altitudes， from 100 to 4300 m.This study systematically presented the distribution， life type， habitat type， botanical characteristics and genetic diversity of Rubus species in southwest China， which provided foundational data for the future development and genetic breeding of Rubus resources.

Abstract:The rice variety Shaoxiang100 with low cadmium accumulation was developed through heavy-ion mutagenesis of the aromatic high-quality rice material 44-5， through applying the M₁TDS technology and the mutation of the OsNRAMP5 gene. The variety Shaoxiang100 underwent multi-location testing in Hunan province from 2021 to 2023， and has also been part of national independent trials for varieties with low cadmium （Cd） accumulation. The mutation of the OsNRAMP5 gene reduces Cd accumulation， and also manganese （Mn）， which is essential for plant growth. This study investigated the Cd accumulation characteristics， yield， quality， and low-temperature tolerance of Shaoxiang100 and its original strain 44-5. These multi-location experiments revealed that Shaoxiang 100 exhibited stable， low levels of Cd in rice grains， with a reduced accumulation of Mn in plants. However， no significant difference was observed in yield when compared to the original variety， 44-5. For main agronomic traits， except for plant height， no significant difference was detected. Both Shaoxiang 100 and the original line 44-5 exhibited a significant decrease in fruiting rate when delay sowing applied. However， late sowing didn’t affect yield or other main agronomic traits， except for plant height.Additionally， the relative cold tolerance coefficient and variety cold tolerance index were 0.75 and 0.75， respectively， indicating a decrease of 47.2% and 49.2%. The low-temperature tolerance at the spikelet stage was classified as level 4， indicating sensitivity to cold. Compared to the original strain 44-5， Shaoxiang 100 did not show a decrease in Mn accumulation or low-temperature tolerance. Both strains were found to have general cold tolerance. Collectively， it is recommended that Shaoxiang 100 as double-crop late rice， can be planted in Hunan and Jiangxi to prevent yield loss from low-temperature stress during the late growth period.

Abstract:Drought resistance in the field is a complex quantitative trait. Accurate phenotypic identification is critical to discover the genes and explore genetic basis for quantitative trait. However， the accurate identification of drought resistance for rice germplasm in the field has consistently been a bottleneck for researcher and a core technical for drought resistance breeders. On the basis of systematic drought resistance research in the previous work， we also have spent many years exploring and optimizing the conditions for assessing drought resistance in the field. The standard technical regulations for evaluating drought resistance in the field were summarized and normalized. It included general requirements， land preparation before sowing， seed preparation， sowing， fertilization， water management， prevention of diseases， pests and weeds， and evaluation of drought resistance in the field at seedling stage. The regulations provided technical reference for identification of drought resistance in the field at seedling stage in rice or other crops. It was suitable for the resistance evaluation of rice to drought during the winter in Sanya of Hainan province （from mid-November to early April of the next year）.