Yams (Dioscorea spp.) are one of the main root and tuber crops in the world, especially within the species complex Dioscorea cayenensis/D. rotundata. Few studies have been conducted in Brazil with these species, including genetic diversity. The objective of this study was to characterize the genetic diversity of local varieties of D. cayenensis and D. rotundata using morphological and molecular markers, and provide information on the management and use of the crop by family farmers from different regions in Brazil. Thus, yam tubers were sampled from several municipalities in the South, Southeast and Northeast regions. Eighteen morphological traits and ten microsatellite loci were used to analyse 47 yam accessions (23 D. cayenensis and 24 D. rotundata). Species identification was carried out after field morphological evaluation. Spatial genetic analysis indicated significant structure among the local varieties, mostly between regions and species. Both cluster and Bayesian analyses showed a separation of the accessions into two distinct groups: group I with accessions originated from the Southeast region and group II with accessions originated from the Northeast region, while accessions from the South region were intermediate or included in either group. The results showed a separation between D. cayenensis and D. rotundata accessions in Brazil, and that D. cayenensis occurs predominantly in the Southeast region, while D. rotundata occurs in the Northeast region. Further studies with larger sampling would be welcome in order to confirm these findings. Also, this study highlights the importance of family farmers in the genetic diversity conservation of these species in Brazil.

The diversity within 20 rice varieties used as progenitors in Cuban rice breeding programmes was analysed with respect to agro-morphological traits, pedigree and DNA markers. Eleven agro-morphological traits were scored, and phenotypic (Euclidian) distances between the rice varieties were calculated. Sixty random amplified polymorphism DNA (RAPD) and 115 amplified fragment length polymorphism (AFLP) bands served to determine Dice's distance estimates. Cluster analyses were performed based on genetic distance matrices using the unweighted pair-group method of arithmetical means (UPGMA) as the clustering method. This analysis showed five phenotypic, six genealogical, five RAPD and six AFLP diversity groups. Genetic diversity estimates based on RAPD data, but not on AFLP, efficiently represented the genetic parentage and phenotypic diversity between rice varieties. Combined diversity estimates allowed the identification of 11 different genetic pools and permitted a more effective separation of the progenitor set than those obtained solely by phenotypic and genealogical information. The results of this study stress the necessity to diversify rice parental stocks for further breeding purposes.

Gloriosa superba L. is a highly valued indigenous medicinal plant. It is available throughout India with noticeable variations in morphology and colchicine content. In the present study, morphological, phytochemical, cytological and molecular data are employed to screen the polymorphism, if present, in five different populations of G. superba L. Based on gross morphological traits, the plants can be grouped into two clusters: Amtala (AM) and Baruipur (BR) plants belonging to one cluster, and Siliguri (SG), Darjeeling (DJ) and Sikkim (SK) plants belonging to the other. Colchicine content of the tubers ranged from 0.06% in AM plants to 0.37% in BR plants. Cytological analysis revealed that the SK plants showed 44 chromosomes, i.e. tetraploid status, whereas the other four were diploid. Assessment of the karyomorphology of the four diploid populations indicated a close similarity between AM and BR plants, whereas the SG plants exhibited slightly different karyomorphology and lacked sm-type chromosomes. Random Amplified Polymorphic DNA (RAPD) analysis revealed 76% polymorphism among the populations. Cluster analysis using RAPD resulted in three main cluster groups; BR and SG plants clustered together indicating that they are most closely related when compared with other populations.

Sheath blight caused by soil borne necrotrophic fungus Rhizoctonia solani [teleomorph-Thanatephorus cucumeris (Frank) Donk.] is a major disease of rice. The disease is increasing over the year in India and cause up to 69% yield loss under favourable conditions. A total of 67 accessions of Oryza nivara were screened to identify resistance against sheath blight during 2015. Out of these, 16 accessions were found moderately resistant (MR) which were further evaluated during the year 2016 and 2017. After three years of screening, 12 of them were found to have a consistent moderate resistant reaction whereas four of the O. nivara accessions namely, IRGC81941, IRGC102463C, CR100097 and CR100110A have shown moderately susceptible to susceptible reaction against sheath blight. A correlation study revealed that different disease variables measured were significantly (P < 0.05) correlated. All the genotypes and genotype × environment interaction had a significant (P < 0.001) effect on all the disease variables. Cluster analysis showed that all the accessions were clustered into four groups which showed resistant, MR, moderately susceptible and susceptible reactions. Among all the O. nivara accessions IRGC81941A showed the maximum potential against sheath blight due to a least relative lesion height of 22.80%. None of the accession had complete resistance to the disease. The identified promising accessions such as IRGC81835, IRGC81941A, CR100008 and CR100111B can be utilized in a sheath blight resistance breeding program.

This paper examines genetic erosion in rice landraces thriving in traditional smallholder agricultural systems in the Sarangani uplands, Philippines. In these marginal areas, the crop is closely interwoven with tribal culture and is vital in ensuring food security among upland households. Field visits unveiled high varietal diversity for upland rice and a rich tapestry of indigenous knowledge associated with its cultivation and use. Study results, however, revealed the tapering of the crop's genetic base due to farmers' changing priorities, pest infestation, weakening seed supply systems, shift to cash crops, natural calamities, environmental degradation, government programmes and peace and order problems. Consequently, these pressures undermined traditional agricultural systems in Sarangani upland communities causing food and water scarcity, hunger and suffering on a catastrophic scale. Interdisciplinary strategies aimed at simultaneously averting further varietal losses and environmental degradation while improving human well-being are therefore warranted. Furthermore, making traditional rice farming a lucrative endeavour will induce the younger generation to remain in the uplands and choose farming as a profession. This way, biocultural restoration of agriculture will be attained and the continued presence of the tribal groups in the Sarangani uplands will be ensured for a very long time.

Variety selection from locally adapted crops is the major climate change adaptation strategy of farming communities. There are several justifications for re-thinking for the sustainable use of crop biodiversity in our breeding programs. Thirty-one durum wheat farmers' varieties (FVs), together with five improved check varieties, were characterized in Tigray during 2014 and 2015 main cropping seasons. The genotype effect explained most of the variations in measured traits, which enabled us to identify superior and stable genotypes for wider adaptation as well varieties with more local adaptation. The genotypes and test locations imposed a highly significant (P < 0.001) effect on both phenological and quantitative traits. A yield advantage of 14.3% was obtained from top performer FV over top performer improved variety, Asassa. Of the tested FVs, 27.8% were superior for grain yield (GY) than improved varieties and 19.4% of these superior FVs were more stable and adaptable than the improved varieties. Besides giving higher GY with spatial stability, they qualify for industrial requirements with high-grain protein (>13%) and gluten (>33%) contents. FVs such as G10, G16, G21, G22 and G30 have wider adaptability and are suitable for production in all tested areas. As outcome of this study, two superior FVs, G10 (208304) and G30 (8208), were nationally released for commercial production for their productivity, stability and grain quality. Utilizing the diverse durum wheat FVs can effectively improve productivity and adaptability. Wheat breeders need to revisit these resources to improve adaptation of wheat production to the changing climatic conditions.

A set of 146 representative adzuki (Vigna angularis var. angularis and var. nipponensis) germplasm from six Asian countries with a tradition of adzuki bean production, together with an outgroup standard rice bean (Vigna umbellata), were analysed by amplified fragment length polymorphism (AFLP) methodology using 12 informative primer pairs. A total of 313 unambiguous polymorphic bands were created. According to the dendrogram, using cluster analysis based on AFLP banding, 143 of the accessions were distinct and revealed enough genetic diversity for identification and classification of accessions within Vigna angularis. A neighbour-joining tree was generated using the newly developed Innan's nucleotide diversity estimate from the AFLP data. From analysis, seven distinct evolutionary groups, named ‘Chinese cultivated’, ‘Japanese cultivated’, ‘Japanese complex-Korean cultivated’, ‘Chinese wild’, ‘China Taiwan wild’, ‘Nepal- Bhutan cultivated’ and ‘Himalayan wild’, were detected. Nucleotide diversity with geographical distribution of each group is discussed, regarding the evolutionary relationships between wild and cultivated adzuki beans. The preliminary results indicated that cultivated adzuki beans have been domesticated from at least four progenitors with at least three geographical origins.

Lentil is now an integral part of prairie cropping systems. Climate forecasts point to variable and increased drought frequency, putting lentil production in jeopardy. Future lentil genotypes will require root systems that can extract more water under drought conditions. This study focuses on root diameter and root tip number, traits known to play an important role in water uptake during drought. We compared the total root length (TRL) in three soil horizons of both wild and cultivated lentil genotypes for three root diameter classes when plants were grown under moderate or severe drought, and when re-watered after exposure to moderate drought conditions. Our study demonstrates that roots of both wild and cultivated lentil genotypes can be categorized into very fine, fine and small diameter classes. Some wild lentil genotypes had significantly higher TRL in the B and C soil horizons when grown under severe or moderate drought and therefore, could act as resources for the transfer of root traits to cultivated lentil genotypes. Further evaluations focused on the root systems of interspecific recombinant inbred lines under drought conditions will be required to determine whether these traits are heritable.

The study of the genetic structure of cultivated plant populations maintained by farmers is of great importance for evolutionary and conservation biology. Such studies help understand the bases of crop evolution and conservation in relation to farmers' practices. In this study, we assessed the genetic structure underlying landrace diversity of dry-season sorghum. This crop constitutes a historical model of innovation developed by farmers to extend sorghum cultivation to the dry season. Two types of dry-season sorghum are cultivated. We aimed to assess the link between farmers' taxonomy and molecular genetic structure. We collected both types of dry-season sorghum in two villages of northern Cameroon which represented 20 landraces. These landraces were genotyped using eight polymorphic microsatellite markers. This study compared two clustering methods: a Bayesian method (STRUCTURE) which is based on explicit genetic assumptions and the discriminant analysis of principal component method. The latter, more recently proposed, is based on the combination of principal component analysis and discriminant analysis. We noticed a general congruence between these two methods. We also used both methods to infer the genetic structure of our sample. Our results showed strong genetic structuring of the landraces, with K= 14 genetic clusters. We then analysed the fit between farmers' taxonomy and genetic structure. The data suggested that each type and each landrace corresponds to a given genetic entity. This pattern was robust across both villages, despite differences in cultural practices.

Recombinant inbred lines (RILs) generated from a cross between a cultivated species and its wild progenitor species serve as important germplasm for introgressing valuable genes from a wild species to a cultivated species. During this breeding process, it is equally important to prevent the loss of agronomically important genes in the cultivated species. In an effort to establish an efficient selection system for the single Rsv1 gene conferring durable resistance to soybean mosaic virus (SMV) in the soybean cultivar Hwangkeum (also known as Suweon 97), which is a parent of a RIL population from Hwangkeum (cultivated soybean) × IT182932 (wild soybean), in the present study, we unexpectedly identified an additional necrosis-conditioning gene unmasked by a recombination in the middle of the Rsv1-containing nucleotide-binding leucine-rich repeat gene cluster region and the Rsv3 gene in Hwangkeum. Thus, Hwangkeum contains at least three SMV resistance genes consisting of two tightly linked genes at the Rsv1 locus and the Rsv3 locus. The results of this study provide additional important information for use of the Hwangkeum genome in soybean breeding programmes.

Germplasm accessions of wild Lactuca species are maintained worldwide in ex situ collections as gene reservoirs for quality and disease resistance traits for cultivated lettuce. Accessions of 12 Lactuca species from 6 genebanks were compared via morphological characterization and AFLP (Amplified Fragment Length Polymorphism)-based profiling to estimate the extent of duplication. A method of assessing redundancy within very similar, but not identical accessions, is proposed, based on 352 polymorphic AFLP products. Seven duplication groups showed a high level of AFLP similarity, and one pair of Lactuca saligna accessions displayed identical AFLP profiles. In several cases, the morphological assessment indicated that a taxonomic reclassification of accessions was necessary. Candidate duplicates were identified using population parameters and inter- and intra-accession variability. The implications of these findings on the conservation of wild species are discussed.

The pattern of inheritance of powdery mildew resistance expressed by two bread wheat (cultivar ‘Alcedo’)/Aegilops markgrafii introgression lines was explored using F2 populations bred from crosses made with the powdery mildew-susceptible cultivar ‘Kanzler’. Disease reaction was tested at both seedling and adult plant stages. Two resistance loci, designated QPm.ipk-1A and QPm.ipk-7A, were identified as mapping to the distal ends of chromosome arms 1AS and 7AL, respectively. Whereas QPm.ipk-1A was expressed throughout the plant's life, QPm.ipk-7A was only effective at the seedling stage. The map location of both resistance loci indicated that resistances originated from A. markgrafii. The possible genetic relationship of these disease-resistant genes to known Pm genes is discussed in the context of synteny.

The present research was conducted to determine the reactions of 200 pure lines selected from bread wheat landraces collected from 18 provinces and seven regions of Turkey against bunt disease (Tilletia foetida) under field conditions for 3 years. Bunt disease reactions of pure lines were assessed based on the infected spike/total spike ratio. For visually assessed materials, the GGE-biplot method, where G = genotype effect and GE = genotype-by-environment effect, was used to group the reactions against bunt disease. Fifty-nine pure lines showed high resistance (with infection rates ranging from 0.1 to 10%); 24 in the moderate resistance (with infection rates ranging from 10.1 to 25%); 75 in the moderate susceptibility (with infection rates ranging from 25.1 to 45%); 38 in the susceptibility (with infection rates ranging from 45.1 to 70%) and finally four in the highly susceptibility (with infection rates of >70.1%). PC1 and PC2 of the GGE-biplot graph created over the years explained 76.49% of the total variation. The GGE-biplot graph provided efficient identification of resistant genotypes. The lowest PC1 values and PC2 values close to 0.0 explained the resistance of pure line to bunt disease best. The resistance of pure lines to bunt disease over the biplot decreased from the first section through the last section. Based on the results of present study, 19 pure lines (located within the first circle of the biplot graph) were selected for resistance breeding programmes against the diseases.

The importance of plant genetic resources for the future of agricultural production and for achieving food security necessitates the study of the factors affecting their most efficient exploitation, particularly in breeding programmes. The established negative correlation between competitive and yielding ability is emerging as an important, yet overlooked cause of seed and variety degradation. Because of this negative correlation, the low yielding, strong competing plants within the variety or the germplasm under study acquire a survival advantage over the high yielding, weak competing plants when propagated under dense stands, leading to a gradual cultivar degeneration and identity loss. Moreover, this gradual degeneration prevents selecting for the positive and novel adaptive variation that is endlessly released by the genome in response to biotic (e.g. mutating pathogens) and abiotic stresses. The application of nonstop selection on individual plants grown in the absence of competition using a novel selection equation demonstrates an effective means to counteract the negative effects and accelerate progress through selection.

This article links the concept of access and benefit-sharing as it pertains to crop genetic resources to climate change adaptation and argues that systems for access and benefit-sharing can, and should, be designed to contribute to climate change adaptation for agriculture. The access and benefit-sharing provisions of the two international agreements that together provide the international legal framework for access and benefit-sharing – the Convention on Biological Diversity (with its Nagoya Protocol) and the International Treaty on Plant Genetic Resources for Food and Agriculture – are presented and analysed. How these agreements are implemented is central to adaptation, as the effects of climate change threaten crop genetic resources and future adaptive capacity, and, if properly maintained and utilized, crop genetic resources will be essential to climate change adaptation across the globe. This article, therefore, argues that an important adaptation strategy linked to such implementation is to direct benefit-sharing for crop genetic resources towards adaptation efforts and to ensure facilitated and efficient access to crop genetic resources for adaptation purposes. Some options for how this can be pursued at both the international and national level are offered.

Sustainable utilization of plant genetic resources for food and agriculture has been increasingly discussed at both national and international forums. Besides exploitation, conservation of plant genetic resources has become an integral part of these discussions. Conservation aims at maintaining the diversity of living organisms, their habitat and the interrelationship between organisms and their environment. For achieving such goals, appropriate conservation strategies have to be adopted. Determining the genetic makeup of a particular plant species is of critical importance when planning a suitable conservation strategy. In this study, we sequenced the chloroplast trnK intron, matK and rbcL gene aimed at understanding the rarity of Nymphaea tetragona, a critically rare and endangered plant of India found at only one location. We extended our investigation to other Nymphaea species such as N. nouchali, N. pubescens and N. rubra that are commonly available throughout India. Interestingly, matK gene of N. tetragona revealed high number of non-synonymous substitutions. Molecular evolutionary analysis indicated that three of these sites may be under mild selective pressures. Such adaptive changes at the DNA and protein sequence level of matK gene may have been associated with the colonization of N. tetragona, suggesting that it could have migrated from China.

Soybean [Glycine max (L.) Merr.] is one of the most important legume crops in the world. However, soybean grain yield is extensively affected by environmental stresses such as soil salinity. In this study, we evaluated the germplasm of 51 Indonesian soybean accessions for salt tolerance to identify salt-tolerant germplasms for possible use in breeding for soybean salt tolerance. Based on experiments under hydroponic conditions, adding 100 mM of NaCl to a 1/2 concentration of Hoagland and Arnon solution, several Indonesian soybean germplasms, such as Java 7, Seputih Raman, Tambora, Ringgit (JP 30217), Sinyonya (early) and Sinyonya (late) were identified as salt-tolerant in terms of salt tolerance rate (STR) and leaf chlorophyll content (SPAD value) taken with the Konica Minolta SPAD-502 chlorophyll meter. The selected salt-tolerant germplasms were further evaluated under soil medium cultivation in pots irrigated with 100 mM NaCl for around 5 weeks. The six selected soybean germplasms again showed higher salt tolerance in terms of SPAD, STR and shoot dry weight. Expression analysis of the salt tolerance gene Ncl revealed a significant positive correlation between Ncl expression and salt tolerance, suggesting that Ncl is essential for salt tolerance in the Indonesian soybean germplasms we tested. The salt-tolerant Indonesian soybean germplasms identified in this study could be used in local soybean breeding practices for the improvement of salt tolerance.

Seed composition, including the protein, lipid and sucrose contents of 334 accessions of wild soybean (Glycine soja) collected in Japan, was evaluated using near-infrared reflectance spectroscopy (NIRS) technology. The distribution of protein, lipid and sucrose contents and correlations among these three classes of seed components were determined. Protein, lipid and sucrose levels ranged in accessions from 48.6 to 57.0, 9.0 to 14.3 and 1.24 to 3.53%, respectively. Average levels of protein, lipid and sucrose in the accessions were 54, 11 and 2.5%, respectively. High negative correlations were observed between the protein and lipid contents, and the protein and sucrose contents. Mean levels of the three constituents were compared among collection sites classified by climatic conditions. The total protein content of accessions from regions with a high annual mean temperature was high. The protein content of accessions from the II-1 region was higher than those from the III-3 region, and the sucrose content from the II-1 region was lower than those from regions III-2 and IV-3. The lipid content of plants from the II-1 region was lower than those from other regions, and the accessions in region II had a higher protein content and lower sucrose and lipid contents than the other regions. These results provide diverse and wide-ranged protein, lipid and sucrose contents information of Japanese wild soybean resources according to climatic region; thus, providing a foundation for the future development and selection of new soybean varieties with desired traits in global environmental changes.

Soybean (Glycine max (L.) Merr.) is an important legume crop with high commercial value widely cultivated globally. Thus, the genetic characterization of the existing soybean germplasm will provide useful information for enhanced conservation, improvement and future utilization. This study aimed to assess the extent of genetic diversity of soybean elite breeding lines and varieties developed by the soybean breeding programme of the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. The genetic diversity of 65 soybean genotypes was studied using single-nucleotide polymorphism (SNP) markers. The result revealed that 2446 alleles were detected, and the indicators for allelic richness and diversity had good differentiating power in assessing the diversity of the genotypes. The three complementary approaches used in the study grouped the germplasm into three major clusters based on genetic relatedness. The analysis of molecular variance revealed that 71% (P < 0.001) variation was due to among individual genotypes, while 11% (P < 0.001) was ascribed to differences among the three clusters, and the fixation index (FST) was 0.11 for the SNP loci, signifying moderate genetic differentiation among the genotypes. The identified private alleles indicate that the soybean germplasm contains diverse variability that is yet to be exploited. The SNP markers revealed high diversity in the studied germplasm and found to be efficient for assessing genetic diversity in the crop. These results provide valuable information that might be utilized for assessing the genetic variability of soybean and other legume crops germplasm by breeding programmes.

Cultivated soybeans [Glycinemax (L.) Merr.] have various flower colours such as dark purple, purple, light purple, pink, magenta, near white and white. About one-third of the soybean accessions in the United States Department of Agriculture – Germplasm Resource Information Network (USDA-GRIN) Soybean Germplasm Collections have white flowers and are the second dominant accessions after the purple-flowered accessions. Earlier studies have shown that the w1 recessive allele of the W1 gene encoding flavonoid 3′,5′-hydroxylase produces white flowers. In the present study, we aimed to understand why the white-flowered accessions have become abundant among the cultivated soybeans and what their genetic and regional origin is. For this purpose, 99 landraces with white flowers and 39 landraces with purple flowers from eight Asian countries and Russia were analysed with regard to the nucleotide sequences of the W1 locus. We not only found that the w1 alleles of the 99 white-flowered landraces were identical to those of the white-flowered Williams 82, but also found that these w1 alleles displayed no polymorphism at all. By carrying out a phylogenetic analysis, we were able to identify a group with W1 alleles from which the w1 allele might have diverged.