In order to clarify the taxonomic status of two special coix germplasm discovered in Xizang of China， their agronomic and taxonomic identification were conducted and the botanical characteristics of the new species were described and illustrated. These twogermplasms were similar to Coix aquatica， but Coix gigantea had plants erect shape； long lanceolate leaves broaden in middle part that looking like hearts， meanwhile the upper and lower layers were coarse and grows glandular hairs in leaf upper surface. Staminate inflorescences is long and thin that generating fertile pollen， enamel involucre or fruit case is pyriform or fusiform in shape， and these typical characteristics were distinguished from those of Coix aquatica. It was estimated by flow cytometry that the genome size of two Coix gigantea were 1578.85 Mb and 1807.92 Mb， whose genomes were diploid type of 2n=2x=20. Phylogenetic analysis indicated that Coix gigantea and Coix aquatica were divided into independent branches in the phylogenetic tree， exhibiting independent genetic lineages. Therefore， Coix gigantea in tegrated evidence from plant morphology， chromosome ploidy and molecular phylogeny all supports that is a newly recorded independent species of the genus in China.

To fully understand the distribution and variation patterns of wild Fagopyrum dibotrys （D. Don） Hara resources， this study conducted field investigations on seven wild populations collected from central and northeastern Yunnan， and performed a systematic diversity analysis based on phenotypic characteristics， secondary metabolites （flavonoids）， and SSR molecular markers. The results showed that the distribution density and population size of Fagopyrum dibotrys were relatively high in northeastern Yunnan， while those in central Yunnan were low and scattered， which may be related to the high degree of industrialization in central Yunnan. Wild Fagopyrum dibotrys in central and northeastern Yunnan exhibited abundant population variation and high plasticity in both phenotypic traits and secondary metabolite profiles， the coefficient of variation ranged from 2.30% to 63.86%. Genetic diversity analysis revealed that different populations possessed varied levels of genetic diversity. The expected heterozygosity of these populations ranged from 0.1435 to 0.2735， and the Shannon's information index varied from 0.2060 to 0.3985. The Ludian population showed the largest distribution density， largest population scale and optimal genetic diversity level（the expected heterozygosity was 0.2735， and Shannon's information index was 0.3985）， suggesting that it may represent a genetic diversity center of Fagopyrum dibotrys in central and northeastern Yunnan. The genetic differentiation coefficient among populations ranged from 0.0203 to 0.2006. The Zhaoyang population exhibited relatively strong genetic differentiation from other populations， which may be associated with the unique climate and geographical location of its distribution area.This study clarified the background diversity and population differentiation characteristics of wild Fagopyrum dibotrys in central and northeastern Yunnan， providing a scientific basis for the precise conservation and innovative utilization of this species.

Ratoon rice possesses multiple production advantages including higher multiple cropping index， superior grain quality， seed and labor savings， reduced water consumption and pesticide application， as well as remarkable economic benefits. Therefore， identifying and evaluating the ratooning ability of germplasm resources is particularly important for developing cultivars with strong ratooning ability. In this study， 241 chromosome segment substitution lines（CSSLs）derived from wild rice and 438 cultivated rice accessions were used as materials. Fourteen phenotypic traits were evaluated in replicated trials over two years to comprehensively assess the ratooning ability of the germplasm. The results showed that the phenotypic coefficient of variation ranged from 2.54% to 49.46% in the wild rice population， and from 4.17% to 33.06% in the cultivated rice population. Among all traits， grain yield per plant in the ratoon season exhibited the highest coefficient of variation in both populations. Correlation analysis revealed that ratooning ability was significantly or extremely significantly positively correlated with plant height， panicle length， number of productive panicles in the ratoon season and ratooning yield per plant， but significantly or extremely significantly negatively correlated with number of productive panicles and seed setting rate. This suggests that developing germplasm with strong ratooning ability requires balanced consideration of traits in both the main and ratoon crops. Five principal components with eigenvalues greater than 1 were extracted by principal component analysis， explaining a cumulative contribution rate of 75.15%. The comprehensive evaluation value for ratooning ability （D values） was obtained by integrating membership function analysis and weight assignment. The D values ranged from 0.24 to 0.74， with a mean of 0.47. Introduced accessions exhibited the best overall ratooning ability， improved cultivars and landraces were at an intermediate level， and the wild rice population showed the poorest ratooning ability but had rich genetic variation， making it suitable for QTL mapping， dissection of single-segment effects， and mining of candidate regions. Representative resources including the introduced accessions IR 83142-60 and IRRI 186， improved cultivars Shuanghuixuan 26 and Xianjinghui 6， the landrace Baike No. 5， and the wild rice line A0792 were identified and can be directly used as core parents with strong ratooning ability in breeding programs. This study clarified the genetic differences in ratooning ability among different types of rice， established a quantitative and applicable comprehensive evaluation index for ratooning ability， and provides material basis and theoretical reference for screening elite ratoon rice germplasm， parent selection， and gene mining for ratooning ability.

Oryza rufipogon Griff.， the direct ancestor of cultivated rice， is a core germplasm resource for rice genetic improvement. At present， the natural habitats of wild rice have suffered severe degradation. Moreover， the in vivo-conserved germplasm in wild rice nurseries is threatened by rice viral diseases， which severely compromised the safe preservation of wild rice resources. In this study， a tissue culture system was constructed， and axillary buds of virus-infected O. rufipogon were used as explants to achieve virus elimination. The results showed that the combination of 5 mg/L 2，4-D and 1 nmol/L OsREF1 could induce callus formation and proliferation from axillary buds， and the combination of 2 mg/L 6-BA and 0.2 mg/L NAA could induce shoot differentiation. The two-step rooting method facilitated root induction and the growth of intact and robust plantlets. RT-PCR showed that the virus-specific bands were absent in the regenerated plantlets. In conclusion， this established system could achieve virus elimination and regeneration of virus-infected O. rufipogon， and provide technical support for the safe preservation of wild rice germplasm resources.

There are three wild rice germplasm resources in China. Compared with Oryza rufipogon and Oryza officinalis， Oryza granulata exhibits more distinct scarcity and endangerment status and utmost importance in protection. At present， the research on the theory of wild rice conservation and the development of conservation technology are relatively lagging behind， and there is a lack of standardized technical guidelines， which results in insufficient support for both ex-situ and in-situ conservation. Based on the results of many years of investigation and experiments， the standard technical regulation for ex-situ conservation of Oryza granulata resources was summarized and normalized. It mainly includes the saving procedures， acquisition of germplasm samples， trial planting and observation， cataloging and organization， ex-situ conservation， planting in the field， field management， monitoring， harvesting， rejuvenation and propagation， distribution， germplasm information. Our study provides technical reference for ex-situ conservation of Oryzagranulata resources. The technical regulations are applicable to ex-situ conservation of Oryza granulata resources.