Different divergence processes of isoglosses of folk nomenclature between wild trees and rice landraces imply the need for different conservation planning based on the type of plant resources

Mitochondrial genome variations have been detected despite the overall conservation of this gene content, which has been valuable for plant population genetics and evolutionary studies. Here, we describe mitochondrial variation architecture and our performance of a phylogenetic dissection of Korean landrace and weedy rice. A total of 4,717 variations across the mitochondrial genome were identified adjunct with 10 wild rice. Genetic diversity assessment revealed that wild rice has higher nucleotide diversity than landrace and/or weedy, and landrace rice has higher diversity than weedy rice. Genetic distance was suggestive of a high level of breeding between landrace and weedy rice, and the landrace showing a closer association with wild rice than weedy rice. Population structure and principal component analyses showed no obvious difference in the genetic backgrounds of landrace and weedy rice in mitochondrial genome level. Phylogenetic, population split, and haplotype network evaluations were suggestive of independent origins of the indica and japonica varieties. The origin of weedy rice is supposed to be more likely from cultivated rice rather than from wild rice in mitochondrial genome level.

Rice landraces or local varieties that have remained in cultivation on-farm are embedded within their agroecological and cultural environment. Rice landraces are genetically diverse, but with a variation that can be well structured, not random. This review examines the population structure and functional diversity revealed in the rice germplasm acquired from farmers in recent decades. Sizable areas of local varieties are found in parts of Asia with distinctive agroecological environment and cultural heritage. A tally of variety names provides a first approximation of diversity, a frequency distribution of the varieties describes a basic structure of diversity in an agroecosystem. Genetic variation is detectable by microsatellites analysis or expressed in specific functional traits, at various organizational levels of the population, even among those exhibiting uniform appearances. The population dynamics of genetically diverse landraces perpetuated by many farmers are shaped by variations in the bio-physical environment and management practices, but those relying on one or two farmers for their maintenance face a risk of extinction. Diversity in widely grown varieties may either be within the farmer’s seed cache, or among populations of the same variety maintained by different farmers. Local rice varieties or landraces continue to play a crucial role in rice farming, the economic value of some is enhanced by their unique grain quality features. Genetically diverse rice landraces that either contribute towards meeting the household’s rice requirement or those that have become commercially successful, also provide an important service in the in situ conservation of germplasm.

BackgroundA complex interaction and mutual influence exists among landscapes, cultures, and landraces, with rice culture being a typical embodiment of this relationship. The conservation of landraces operates alongside preserving traditional practices. The Xishuangbanna region stands out as a hub for the genetic diversity of landraces, boasting rich genetic resources. Despite the diverse rice resources in this region, a comprehensive and systematic study has not been undertaken.MethodsFrom October to November 2023, we collected rice landraces under the on-farm conservation in 18 townships including Menghai, Mengla and Jinghong in Xishuangbanna. Employing semi-structured interviews and various methods, we investigated factors influencing the preservation and loss of rice landraces in the region. Statistical analysis was applied to the agronomic traits of collected local rice, encompassing indica or japonica, glutinous or non-glutinous, grain shape, and hull color as second category traits. The second category included quantitative traits like thousand grain weight and grain length. Rice diversity among different regions, traits, and ethnic groups was assessed using the Shannon–Wiener index. Additionally, clustering analysis via the UPGMA method depicted the distribution characteristics of the resources.ResultsA total of 70 rice landraces were collected in the Xishuangbanna region, each exhibiting distinct characteristics. Differences were observed across regions, trait, naming, and ethnic groups. Diversity analysis revealed that Mengla had the highest diversity, followed by Menghai, while Jinghong exhibited the lowest diversity. The second category of traits displayed broader diversity than the first, with the Dai people’s glutinous rice showcasing greater diversity than other ethnic groups. Cluster analysis categorized the 70 samples into seven groups at a genetic distance of 1.15. Ethnobotanical interviews emphasized the rapid loss of rice landraces resources in Xishuangbanna, with indigenous ethnic cultures playing a vital role in the conservation of rice landraces. Dai traditions, in particular, played a crucial role in protecting glutinous rice resources, showcasing a mutual dependence between Dai culture and glutinous rice.ConclusionsThe rich natural environment and diverse ethnic cultures in Xishuangbanna have given rise to various rice landraces. The Dai, primary cultivators of glutinous rice with higher diversity, intertwine their traditional ethnic culture with the conservation of glutinous rice resources. At the same time, the preserving glutinous rice resources promotes the inheritance of Dai ethnic culture. However, rice landraces are facing the risk of loss. Hence, collecting and documenting rice landraces is crucial. Encourage local communities to sustain and expand their cultivation, promoting on-farm conservation. These measures contribute valuable germplasm and genes for rice breeding and serve as a means of cultural preservation.

Folk Rice Diversity of Eastern India- Hope for The Future Food Security

The coastal regions of Bangladesh host a rich diversity of Aman rice landraces, which are crucial for local agriculture but are highly vulnerable to natural disasters like cyclones and floods. Specifically, local landraces often experience flooding during grain filling and maturation stages, and sprouts in the field lead to a severe loss of yield. Seed dormancy, which delays germination, is a key trait for escaping sprouting in the field during harvesting. However, there is lack of information on genetic variability in the existing rice landraces grown in the coastal area of Bangladesh. This study evaluated the seed dormancy of 28 local Aman rice landraces, plus four varieties from the Bangladesh Institute of Nuclear Agriculture and Bangladesh Rice Research Institute. Germination tests were conducted under controlled conditions, and an electrical conductivity (EC) test was used to assess seed vigor. The results showed that Bari Mota, Tulsimala, Chinigura, Dishari, and Birindi exhibited the highest dormancy rates, i.e., 100%, 100%, 99%, 99%, and 99%, respectively, while BINA Dhan 10, Nona Bokra, and BINA Dhan 8 had the lowest dormancy rates, with values of 11%, 16%, and 24%, respectively. Priming treatments enhanced germination rates in some varieties; however, others, such as Bari Mota and Tulsimala, remained dormant, underscoring the variability in seed dormancy levels. Compared to non-priming, a significant improvement of germination was recorded in BRRI dhan 41 (85.3% vs. 9%), Motha mota (84% vs. 8%), Lal chikon (74.6% vs. 1%), Sadamota (74.6% vs. 5%), and Bashful (53.3% vs. 3%). Altogether, our results suggest that local landraces are diverse in seed dormancy, and genotypes with high dormancy, such as Bari Mota and Tulsimala, can potentially be grown in the disaster-prone coastal areas. In contrast, these genotypes can be used for future breeding programs. Therefore, this study carries significant implications for rice cultivation in the coastal areas of Bangladesh.

Crop plant improvement depends on genetic diversity. The regional collections contain a variety of genes, some of which are useful despite the shifting socioeconomic and environmental/climatic circumstances. Plant breeders can produce new and enhanced cultivars with desirable features by utilizing the diversity of available plant genetic resources. Twenty five traditional rice (Oryza sativa L.) landraces from the NorthWest Himalayan region of Kashmir were assessed for cooking quality and physic-chemical characteristics. The majority of the cooking quality traits, such as kernel length before and after cooking, kernel breadth before and after cooking, amylose content gel, consistency, and alkali spreading value, showed a wide range of variability in the rice landraces under study. Extensive genetic variety across the landraces under investigation, which may be used for agricultural development programs, was suggested by the wide variation among the morphological and other cooking quality parameters.

The traditional landraces of rice plant had a major role in building socio-economic status of rural poor. The present study deals with the diversity and ethnobotanic significance of indigenous landraces of rice in Lakhimpur district of Assam, India. Altogether, twenty-one indigenous landraces of rice were collected during the present study. Each class having important role to play, the major classes of rice include glutinous, common rice and aromatic rice. Other than being a staple food, rice and its products are still frequently used by rural folk in various festivals, religious and social ceremonies in the form of sweets, cakes, snacks and beverages. Bora-dhan was reported with the highest use value. Based on grain’s qualitative and quantitative traits, the obtained dendrogram contains four different clusters; while, the OTUs (Operational taxonomic unit) present in a cluster display morphological similarity. The dendrogram also illustrated diversified distribution of grains in this region. The study also reveals the profound relationship of people with the traditional landraces of rice. The ethnic farmers should be made aware to promote on-farm conservation of crop diversity, before it is lost under the debris of modernization.

Karim-Aly S. Kassam: Biocultural Diversity and Indigenous Ways of Knowing: Human Ecology in the Arctic

Climate change poses a threat to global rice production by increasing the frequency and intensity of extreme weather events. The widespread cultivation of genetically uniform modern varieties has narrowed the genetic base of rice, increasing its vulnerability to these increased pressures. Rice landraces are traditional rice varieties that have been cultivated by farming communities for centuries and are considered crucial resources of genetic diversity. These landraces are adapted to a wide range of agro-ecological environments and exhibit valuable traits that provide tolerance to various biotic stresses, including drought, salinity, nutrient-deficient soils, and the increasing severity of climate-related temperature extremes. In addition, many landraces possess diverse alleles associated with resistance to biotic stresses, including pests and diseases. In addition, rice landraces exhibit great grain quality characters including high levels of essential amino acids, antioxidants, flavonoids, vitamins, and micronutrients. Hence, their preservation is vital for maintaining agricultural biodiversity and enhancing nutritional security, especially in vulnerable and resource-limited regions. However, rice landraces are increasingly threatened by genetic erosion due to widespread adoption of modern high-yielding varieties, habitat loss, and changing farming practices. This review discusses the roles of rice landraces in developing resilient and climate-smart rice cultivars. Moreover, the Pantiange Heigu landrace, cultivated at one of the highest altitudes globally in Yunnan Province, China, has been used as a case study for integrated conservation by demonstrating the successful combination of in situ and ex situ strategies, community engagement, policy support, and value-added development to sustainably preserve genetic diversity under challenging environmental and socio-economic challenges. Finally, this study explores the importance of employing advanced genomic technologies with supportive policies and economic encouragements to enhance conservation and sustainable development of rice landraces as a strategic imperative for global food security. By preserving and enhancing the utilization of rice landraces, the agricultural community can strengthen the genetic base of rice, improve crop resilience, and contribute substantially to global food security and sustainable agricultural development in the face of environmental and socio-economic challenges.

The International Conference on Biological and Cultural Diversity held in Montreal on June 2010, produced the Declaration on Biocultural Diversity and the UNESCO-SCBD Joint Programme on the linkages between cultural and biological diversity. The first meeting for the implementation of the Joint Programme was held in Florence (Italy) in April 2014. The scientific and policy dimensions of the linkages between cultural and biological diversity are of utmost importance in Europe where policies are devoted to the conservation of biodiversity and cultural heritage, but rarely focused on the result of interactions between nature and culture expressed by the rural landscape. The Florence Conference gathered scientists from different disciplines considering biocultural diversity as a good example of a topic requiring a transdisciplinary approach not always supported by university and research. This not only for an effective understanding of the biodiversity associated with landscapes shaped by the man, but also for the further development of the Joint Programme in terms of research and political implementation. The meeting was organized into a scientific part and a workshop for the drafting of a declaration on biocultural diversity. The declaration states that the European rural landscape (about 80 % of the European Union territory) is predominantly a biocultural multifunctional landscape, while the current state of biological and cultural diversity in Europe results from the combination of historical and ongoing environmental and land-use processes and cultural heritage. This book shows the existence and the importance of biocultural diversity associated to European landscape. This heritage should be studied, preserved and valorized by public policies.

The genetic relationship analysis of local glutinous rice is very important for genetic management, conservation and new varietal selection. The experiment was conducted during 2018-19 at Dien Bien district, Dien Bien province, Vietnam to assess the agro-morphological characteristics and genetic diversity of 42 accessions of glutinous rice landraces. Results showed that the varieties have relatively diverse growth times, are largely middle-day group, and mainly medium-to-high plant height with weight of 1000 grains from medium to high majority. In addition, Polymorphic Information Content (PIC) was calculated by using 35 polymorphic SSR markers. Then a cluster analysis of rice collection was performed from the similarity matrix using the Unweighted Pair- Group Method Analysis (UPGMA). The results investigated a total of 106 alleles with an average of 3.03 per locus. PIC values ranged from 0.08 to 0.84, with an average of 0.5. The genetic similarity coefficient of 42 studied rice landraces ranged from 0.63 to 0.97. Based on UPGMA for molecular data using NTSYS-pc 2.1, 42 glutinous rice landraces were divided into 7 groups with genetic differences which could possibly lay a foundation for the development of glutinous rice varieties in Vietnam.

India is blessed with an abundance of diverse rice landraces in its traditional cultivated areas. Two marker systems (simple sequence repeats (SSR) and single nucleotide polymorphism (SNP)) were used to study a set of 298 rice landrace accessions collected from six different regions of India (Andaman and Nicobar Islands, Chhattisgarh, Jharkhand, Uttar Pradesh, Uttarakhand, and West Bengal). Thirty hyper-variable simple sequence repeats (HvSSRs) and 32,782 single nucleotide polymorphisms (SNPs) were used in inferring genetic structure and geographical isolation. Rice landraces from Uttar Pradesh were the most diverse, with a gene diversity value of 0.42 and 0.49 with SSR and SNP markers, respectively. Neighbor-joining trees classified the rice landraces into two major groups with SSR and SNP markers, and complete geographical isolation was observed with SSR markers. Fast STRUCTURE analysis revealed four populations for SSR markers and three populations for SNP markers. The population structure with SSR markers showed that few individuals from Uttarakhand and Andaman and Nicobar Islands were grouped in small clusters. Population structure analysis with SNP markers showed not very distinct region-wise clustering among the rice landraces. Discriminant analysis of principal components (DAPC) and minimum spanning network (MSN) using SSR markers showed region-wise grouping of landraces with some intermixing, but DAPC and MSN with SNP markers showed very clear region-wise clustering. Genetic differentiation of rice landraces between the regions was significant with both SSR (Fst 0.094–0.487) and SNP markers (Fst 0.047–0.285). A Mantel test revealed a positive correlation between the genetic and geographic distance of rice landraces. The present study concludes that rice landraces investigated in this study were very diverse, and unlinked SSR markers show better geographical isolation than a large set of SNP markers.

Biocultural diversity, which refers to the inextricable link between biodiversity and cultural diversity, has been predominantly associated with the traditional ways in which indigenous people in tropical countries interact with the natural environment. But it does not have to be restricted to these circumstances. Biocultural diversity may also be regarded as an interesting concept for understanding how people in industrialized and globalized societies deal with nature. This paper explores biocultural diversity in 20 European cities by considering (i) how biocultural diversity is interpreted in urban planning and governance, and (ii) what actual manifestations of biocultural diversity are present in these cities. Despite the fact that the concept of biocultural diversity was hardly recognized by city authorities, interviewees gave many examples of how biodiversity and cultural diversity are taken into account in (in) formal city policies. The research revealed two main manifestations of biocultural diversity within urban Europe: biocultural diversity grounded in ecological features, and cultural values as a basic foundation for biocultural diversity. Consequently, urban biocultural diversity was found to have two spatial levels: the city level and the site level. The former is the domain of governmental policy makers who discuss biocultural diversity in ‘green space networks’ in a rather static way. The latter is the domain where citizens participate in decisionmaking and the management of green spaces; it is here that cultural dynamics are most acknowledged.

Greater insight into the dynamics of genetic resources of crop plants is needed in order to pinpoint detrimental evolutionary patterns and draw up conservation priorities. The present study demonstrated farmer management of crop population structure and temporal evolution of rice genetic diversity in traditional production systems. The 16 STMS primers analysed for 11 rice landrace populations indicated enough polymorphism to fully differentiate the inter‐ and intrapopulation diversity. A total number of 98 alleles were recorded, of which 91 were common and seven were rare. The mean number of alleles per locus was 6.13 and for different groups of rice landrace populations, namely five populations of upland common landrace Jaulia, three populations of irrigated common landrace Thapachini and one population each of three distinct rare landraces were 4.37, 2.75 and 4.37, respectively. The study also compared genebank‐conserved (ex situ) populations and on‐farm‐managed (in situ) landrace populations of same named landraces Jaulia and Thapachini, and revealed greater number of alleles per locus for on‐farm‐managed populations as compared to the populations under static management. A substantial number of alleles specific to populations under dynamic management could also be recorded. Further, the rare landrace populations included in the present study were more diverse than the common landrace populations. The rare landraces were distinct genetic entities largely representing locally common alleles. Investigating the population genetic structure is therefore helpful in monitoring change in diversity over time and space, and also for devising a rational plan for management of farmer landraces on‐farm.

Rice landraces, a genetic reservoir for varietal improvement, are developed by farmers through artificial selection during the long-term domestication process. To efficiently conserve, manage, and use such germplasm resources, an understanding of the genetic structure and differentiation of local rice landraces is required. In this study, we analyzed 188 accessions of rice landraces collected from localities across an altitudinal gradient from 425 to 2, 274 m above sea level in Yunnan Province, China using ten target genes and 48 SSR markers. We detected clear differentiation of the rice landraces into indica and japonica groups and further separation of the accessions in each group into two subgroups according to altitude, including a lower altitude subgroup and higher altitude subgroup. The AMOVA results showed significant genetic differentiation among altitude zones at SSRs and most genes, except Os1977 and STS22. We further determined that differentiation among landrace populations followed a model of isolation by altitude, in which gene flow was higher among populations at similar altitude levels than across different altitude levels. Our findings demonstrated that both adaptation to altitude and altitude-dependent gene flow played key roles in the genetic differentiation of rice landraces in Yunnan, China.