Andean arracacha (Arracacia xanthorrhiza Bancr.) is a valuable but poorly known vegetatively reproduced root crop whose origin is still unresolved. Wild tuberous forms are present in the presumed areas of domestication and have a perennial or monocarpic life history. To elucidate the origin of the cultivated form, we surveyed a molecular analysis with amplified fragment length polymorphisms (AFLPs) in a representative sample of this crop and its wild relatives from Ecuador and Peru, the presumed areas of domestication. Wild species with tuberous and non-tuberous roots were included, as well as the perennial and monocarpic forms of the presumed wild ancestor. While the two wild varieties of A. xanthorrhiza were closest to the cultivars, they were distinguished by AFLPs. Unexpectedly, two clearly distinct groups were formed among the cultivars, one of which was significantly closer to the monocarpic wild form. However, the chloroplast DNA survey revealed greater similarity between all of the cultivars and the wild perennial A. xanthorrhiza. These results combined with the morphological and life history features, confirms the hypothesis that arracacha domestication started from the wild perennial form. We suggest this scenario of domestication followed by an unsuspected introgression in the cultivation, resulting in two cryptic genetic groups, well distinguished at the molecular level. This is an important revelation with implications in genetic resource conservation and breeding standpoints in this promissory crop.

Brassica species have an economic and medicinal importance. Estimation of the amount and distribution of genetic diversity within Brassica species is essential for establishing efficient management, conservation and breeding practices. This review discusses the taxonomy, gene pool, and Brassica-derived phytochemicals and their nutraceutical importance. It also surveys the recently advanced studies of the genetic diversity and phylogenetic studies of Brassica species at the level of morphological, cytological, biochemical and molecular markers that have proven to be useful for evaluating the genetic variation, taxonomic relationships and species identity, and could be useful for improving Brassica crops through future promising breeding programmes.

Identification and characterization of the farmers’ named crop varieties cultivated around the world is a major issue for conservation and sustainable use of plant genetic resources. Intraspecific diversity is strongly determined by farmers’ socio-cultural environment, but this has little been documented. In this paper, we tested, on a contact zone among three ethnolinguistic groups located on the Mount Kenya region, whether farmers’ socio-cultural differences have an impact on the morphological characteristics of the farmers’ named sorghum varieties. Eighteen qualitative morphological traits of the panicles were measured. We first compared the morphological diversity of the named varieties among ethnolinguistic groups using multivariate analysis of homogeneity of groups’ dispersion and tested their differentiation using permutational multivariate analysis of variance. Discriminant analysis of principal components was then used to categorize the morphological diversity without a priori, and this classification was compared with farmers’ local taxonomy (vernacular names) in the three ethnolinguistic groups. Our results show that some morphotypes are peculiar to some ethnolinguistic groups and that a morphotype can bear different variety names while the same variety name can be used to identify different morphotypes. Morphological differentiation that was explained by ethnolinguistic groups was higher for local landraces than for improved varieties. Our findings imply that socio-cultural diversity of farmers and the criteria they use to identify and maintain landraces need to be considered in studying and sampling crop diversity for in situ as well as for ex situ conservation.

Rice yield improvement is required to support increasing global rice demand. However, the limited genetic diversity within the cultivated rice gene pool may be a major obstacle. Australian wild rice which has been largely genetically isolated from cultivated rice might be a new source of genetic variation for use in improving rice production. The physical properties of Oryza australiensis and of the two perennial Australian Wild rice taxa-belonging to the A genome wild rice were evaluated. Seeds collected from rice in the wild were generally smaller than those from domesticated rice. The wild rice A genome collections were classified as extra-long paddy rice with grains that were long or medium, while O. australiensis was categorized as long paddy rice with a short grain. However, these wild rices were slender compared with domesticated rice. The grain colour of these wild rices varied from light red brown to dark brown compared with domesticated rice which is brighter, with less redness and more yellowness than the wild rice. The physical characteristics of the grains of the Australian wild rice indicate that these rice grains may be successfully processed using current rice processing techniques and may be a useful novel food especially in the coloured rice market.

Acetohydroxyacid synthase (AHAS) inhibiting herbicides have played a significant role in effective weed control in the cultivation of sunflower since their discovery. The development of sunflower lines and hybrids resistant to these herbicides made their post-emergence application possible. In this study, wild Helianthus species were screened phenotypically for imidazolinone (IMI) and sulfonylurea (SU) resistance by herbicide spray and for allelic variations at Ahasl1 (Ahas1 large subunit) locus using simple sequence repeat and single nucleotide polymorphism markers. Helianthus praecox accession 1823 plants showed promising resistance to three classes of SU-based herbicides and Helianthus nuttallii accession NUT05 plants remained green for a longer time after imazethapyr spray. A total of 50 accessions belonging to 21 wild Helianthus species of different ploidy levels were analysed for allelic variation along with some parents of commercial sunflower hybrids. None of the wild species showed the resistant allele (Ahasl1-1) similar to SCG101 (IMI-resistant line), although it is present in some of the parental lines of hybrids. However, the parental lines having Ahasl1-1-type allele failed to survive the field dose of imazethapyr spray. Inter-species and inter-accessional allelic variation could be observed among the species. PRA1823 and NUT05 showed repeat length variations at Ahasl1 locus. Sequencing of full length Ahasl1 gene from both these accessions did not reveal any resistance mutations in the protein sequences. The molecular basis of the phenotypes identified in this study could be explored further and utilized in breeding programmes for imparting herbicide resistance in cultivated hybrids across sunflower growing regions of the world.

Amylose-free (waxy) maize has been a vegetable (cooked ears) and staple food in Southeast Asia for centuries, resulting in hundreds of landraces (LRs) across the region. The recessive waxy allele induces soft grains with preferred cooking and flavour properties. We hypothesized that eating preferences resulted in the additional selection for different starch properties, reflected in altered starch granule morphology or amylopectin structure. A total of 41 LRs were available as starting material that had been used by different ethnic groups in Vietnam and Thailand. Unluckily, some LR were not pure waxy, but we successfully regained the original pure waxy status for most. Twenty LR were chosen for analysis of starch traits according to their purity. Four different waxy mutations were identified, including two unknown alleles. This is a strong proof for parallel independent selection of waxy maize in the region. Starch granule morphology and size were similar among all LRs. Gelatinization properties differed only between waxy and wild-type LR, and all waxy LR were comparable to a commercial waxy hybrid. The fine structure of waxy amylopectin had fewer short chains compared with that in wild-type. So far, the differences observed in starch properties are likely associated exclusively with the waxy trait. Despite the strong selection for amylose-free starch, there was no evidence for additional region wide selection for other special starch properties in our collection. In conclusion, all analyses did not encourage further targeted research on allelic variation of other starch metabolism genes for future use in the food and feed industry.

The world collection of pearl millet at ICRISAT genebank includes 19,696 landraces. Passport and characterization data of 2,929 accessions belonging to 89 named landraces originating in 15 countries of Africa was used to study the adoption pattern and genetic potential. Out of 89 named landraces under study, 71 were grown in one country, 11 in two countries, six in three countries and one in four countries. Latitude and prevailing climate at collection sites were found as the important determinants of cultivation pattern of landraces. A hierarchical cluster analysis using 12 agronomic traits resulted in five clusters. Cluster 1 for late flowering, short height in rainy season, high tillering and thin panicles; cluster 2 for early flowering; cluster 3 for stout panicles in both the seasons and larger seeds and cluster 5 for longer panicles in both seasons, were found as promising sources. IP 8957, IP 8958, IP 8964 of Iniadi landrace for short height, downy mildew and rust resistance and high seed iron and zinc contents; IP 17521 of Gnali (106.9 ppm) and IP 11523 of Idiyouwe (106.5 ppm) for high seed iron content; IP 17518 of Gnali (79.1 ppm) and IP 11535 of Iniadi (78.4 ppm) for high seed zinc content were the important sources. All accessions of Raa for high seed protein content (>15%) and those of Enele for drought tolerance, were found to be promising sources. Further evaluation of promising sources identified in this study is needed for enhanced utilization of germplasm in pearl millet improvement.

The wild species of tomato Solanum pennellii (Lpa) is more tolerant to salt-induced oxidative stress than the cultivated species Solanum lycopersicum (Lem), due to the increase of several antioxidative metabolites and enzymes in this species under stress. The increase of reduced glutathione (GSH), one of these metabolites, in NaCl-treated Lpa, is due at least partly to the elevation of γ-glutamylcysteine synthetase (γ-ECS). Introgression line IL 8–3, which was found to include the Lpa orthologue of the γ-ECS gene (Lpa γ-ECS) in Lem's genetic background, was used to assign this gene to chromosome 8 and to assess its relative contribution to the effective antioxidative response of Lpa to stress. The growth of IL 8–3 and Lem plants responded similarly to NaCl and cadmium (Cd) stresses. In both genotypes, GSH and H2O2 levels responded also similarly to NaCl stress. NaCl and Cd stresses affected similarly the transcription of the γ-ECS gene in leaves of both IL 8–3 and Lpa plants. The effect of buthionine sulfoximine (BSO), a competitive inhibitor of the γ-ECS enzyme, on γ-ECS transcription was also similar in these two genotypes. Taken together, these results suggest that γ-ECS orthologues differ mainly in the regulation of their transcription and not at the post-transcriptional or translational levels. The mutation(s) led to these differences in the response of the two orthologues to the salinity and heavy metal stresses are expected to occur in a cis-regulatory element(s) located relatively close to γ-ECS.

Choclero is a Chilean traditional floury maize, consumed as a vegetable, with large economic and cultural value due to its culinary properties that give unique characteristics to the traditional local cuisine. Market diversification demands new materials with different ear and kernel characteristics, which are at present not fulfilled by breeders due to lack of genetic diversity. At present, the Instituto de Investigaciones Agropecuarias has a Choclero germplasm collection composed of 96 accessions, which can supply this lack of diversity, or increase the gene pool. In the present study, 34 selected Chilean Choclero landraces were characterized for 41 agromorphological traits. Phenotypic evaluation in three environments representative of the core production area revealed significant genetic variability for most of the evaluated traits, leading to the identification of several promising accessions. The greater contribution of genotype in most phenological plant, ear and kernel traits suggest their potential usefulness for breeding purposes. Principal component analysis explained over 75% of the total variation for 29 quantitative agromorphological traits. Cluster analysis separated accessions into four major groups, differentiated mainly by plant phenology and ear trait. These findings indicate a number of useful traits at an intra-racial level and a wide range of phenotypic variation that provides a good source of diversity for use in the development of new Choclero varieties.