The objectives of this study were to analyse the maize diversity in the southeast of Coahuila State in Mexico and to identify a representative subset that encompasses the majority of the diversity in the region of study. Seventy-seven native maize populations were first explored and given a race classification followed by a morphological description based on selected quantitative ear traits using 10 representative ears from the collected samples. The differences between maize populations from the adaptation area and the relationships between and within groups in the region of study indicate the usefulness of the ear traits to describe maize diversity. Two main groups were identified that summarized the maize diversity. The first group, the conical ear complex, includes populations adapted to highland altitudes (Conico Norteño Race). The second group, the cylindrical ear complex, represents populations adapted to lowland and intermediate altitudes (Raton and Tuxpeño Norteño). Using the phenogram, a subset of 18 out of the 77 maize populations (23.4%) was defined that accounts for the variation between and within the different race complexes. This subset also includes at least one representative population from each of the less represented types. The final subset, representing a sample of maize diversity, can be used to establish strategies for conservation and use, such as participatory conservation and management, or it can be used to develop breeding techniques for improving the land race populations within the region of study.

Wild and managed bees are needed to move sunflower (Helianthus annuus L.) pollen, both to create hybrid seed and to encourage high, consistent yields when those hybrids are subsequently grown. Among floral traits that influence bee preference, floret size may be critical, as the depth of the corolla affects the accessibility of nectar. Sampling and observation of inbred maintainer (HA) lines were used to assess variation in floret size, and to measure any effects of floret size on pollinator visitation. Among 100 inbreds sampled, there was significant variation among the lines, with floret lengths of 6.8–9.9 mm. Floret length, measured before anthesis, was closely related to corolla depth during anthesis and was consistent between 2 years (environments). Pollinator observations on 30 inbred lines showed floret size explained a majority (52%) of the variation in wild bee preference, with a reduction in floret length of 2 mm more than doubling pollinator activity. Though honey bee, Apis mellifera L., colonies were located ≈ 60 m from the plots, near-zero honey bee activity in the sunflowers precluded an assessment of how strongly this managed pollinator is affected by floret length. Production of inbreds and hybrids with smaller florets could enhance sunflower pollination, but genetic markers for floret size are needed to facilitate selection, and an understanding of potential trade-offs also is required. Information on variation and heritability of other traits, such as pollen and nectar rewards, could help explain residual variation in wild bee visitation to sunflowers.

This study was conducted to characterize new plant type (NPT) traits among 650 genetically diverse rice genotypes of tropical japonica and indica and to establish an initial core set for NPT traits. Analysis of variance revealed highly significant differences among the genotypes for all the traits assessed except flag length and width and leaf angles. Dendrogram categorized the genotypes into five distinct duration groups. Genotypes viz., Pumphamah, IRGC5097, IRGC37015, IRGC43741, IRGC50448, IRGC53089, IRGC39111, IRGC18021, Haorei Machang, IRGC44069, IRGC8269, Thangmoi, IRGC33130 and IRGC29772 were identified as possessing strong culm. Long panicles with a length of more than 35 cm were found in IRGC8269, IRGC9147, IRGC14694, IRGC19642, IRGC27435, IRGC39111, IRGC31051, IRGC26011and IRGC25892. Ideal leaf angle of NPT genotypes of 5°, 10° and 20° of flag leaf, 1st and 2nd leaves was not found in any genotype but with a combination of 5°, 10° and 10° was observed in IRGC63102 and IRGC66644. NPT flag leaf length and width of 50 and 2 cm, respectively, was seen in ‘Kemenya Kepeu’ and ‘IRGC29772’. High grain number of more than 350 was observed in IRGC53089, IRGC31063 and Azhoghi. A total of 72 genotypes were found with a combination of one or more ideal plant type traits of which, hierarchical cluster analysis based on genetic distances selected 32 as NPT core set. This core set will serve as an ideal genetic resource for breeding programs aimed at NPT development.

This study is the first assessment of the entire soybean [Glycine max (L.) Merr] collection of the United State Department of Agriculture National Plant Germplasm System (USDA) reporting quantitative and population genomic parameters. It also provides a new insight into soybean germplasm structure. Germplasm studies enable plant breeders to incorporate novel genetic resources into breeding pipelines to improve valuable agronomic traits. We conducted comprehensive analyses on the 19,652 soybean accessions in the USDA-ARS germplasm collection, genotyped with the SoySNP50 K iSelect BeadChip SNP array, to elucidate the quantitative properties of existing subpopulations inferred through hierarchical clustering performed with Ward's D agglomeration method and Nei's standard genetic distance. We found the effective population size to be approximately 106 individuals based on the linkage disequilibrium of unlinked loci. The cladogram indicated the existence of eight major clusters. Each cluster displays particular properties with regard to major quantitative traits. Among those, cluster 3 represents the tropical and semi-tropical genetic material, cluster 5 displays large seeds and may represent food-grade germplasm, and cluster 7 represents the undomesticated material in the germplasm collection. The average FST among clusters was 0.22 and a total of 914 SNPs were exclusive to specific clusters. Our classification and characterization of the germplasm collection into major clusters provides valuable information about the genetic resources available to soybean breeders and researchers.

The conservation of pineapple in urban backyards is an innovative strategy that aims to involve city residents. A program of this nature requires careful planning and monitoring because of the involvement of people who do not have technical knowledge. This paper reports the implementation and evaluation of 30 gardens in urban backyards in Cabaceiras do Paraguaçú, Bahia, Brazil, to establish the parameters to allow creating a model for pineapple germplasm conservation cells with the collaboration of urban residents. A questionnaire was applied in two steps to people interested in participating, from which it was possible to choose and evaluate a general profile of the participants. Thirty pineapple accessions from the Active Germplasm Bank (AGB) of the Embrapa were selected for testing in the gardens. Two production cycles were considered, during which quantitative and qualitative traits of the plants and fruits were evaluated. The data were compared with the characteristics of the same accessions in the Pineapple AGB and were analysed by mixed principal component analysis. With respect to adequate maintenance, 20 gardens were well cared for until the end of the assessments, five were reasonably well tended and five were lost, due to home remodelling or lack of care by the guardians. Despite the loss of the five gardens, no accession was totally lost, thanks to the experimental design with three plants of each accession in three different gardens. The plants preserved in the gardens did not differ from those maintained by the AGB, demonstrating the effectiveness of this conservation strategy.

Cassava brown streak disease (CBSD) remains a major threat to cassava production in Mozambique. Breeding for CBSD resistant varieties that are also preferred by farmers is an integral part of managing the disease. The main objective of the study was to determine the genetic relationship between farmer-preferred varieties from Mozambique with those from Tanzania whose resistance to CBSD is known and some of which are being used as parents in quantitative trait loci (QTL) detection studies. To achieve this, 103 genotypes collected from farmers’ field in three provinces of Mozambique were genotyped together with five varieties from Tanzania whose CBSD response is well known. Thirty-five single nucleotide polymorphism (SNP) markers with a high minor allele frequency in East African landraces were used. Results indicated that seven Mozambican genotypes were genetically similar to either one of the four Tanzanian CBSD resistant genotypes while Xino Nn'gole was genetically identical to Namikonga a CBSD resistant variety, based on the SNPs used here. Little genetic differentiation was observed in cassava between provinces, with the majority of genetic variation distributed within individual genotypes (98%) rather than among provinces (2%). Both observed (Ho) and expected (He) heterozygosity in three provinces were generally high (Ho = 0.496) and (He = 0.455). There is a high likelihood that the eight genotypes similar/identical to those from Tanzania may share the same QTL associated with CBSD resistance thus should be further evaluated for agronomic traits as well as response to CBSD.

Drought is a major constraint to oil palm plantation in many regions relying on rainfall. One strategy to overcome this problem is to develop drought-tolerant cultivars through screening and selection. Drought tolerance assessment based on growth and physiological traits provides an alternative approach for rapid screening especially in tree crops. The aims of this study were to determine the contribution of some growth and physiological parameters to drought response variation in oil palm seedling and to use those parameters to evaluate relative drought stress tolerance in tenera oil palm progenies. Eight D × P progenies were grown under well-watered, moderate and severe stressed conditions for a total of 6 months. Data on growth traits, maximum quantum yield (Fv/Fm), SPAD value and proline content were recorded. Principal component analysis (PCA) on studied traits revealed that PC1 and PC2 explained 74.57 and 76.80% of total variance in moderate and severe drought treatments, respectively. Major contributions towards the variation of control and drought-treated plants were identified and appeared to be growth traits in moderate drought stress and growth trait plus proline content in severe drought stress. According to drought tolerance index, PCA analysis and ranking method using integrated PCA values, PSU-106 and PSU-206 were identified to be relatively high tolerant to severe drought stress, while PSU-106, PSU-128, PSU-206 and PSU-208 were tolerant to moderate drought stress. Field validation of D × P progenies selected as drought tolerance is recommended to establish this indirect selection approach in oil palm breeding programme.

Triticum monococcum ssp. monococcum has useful traits for bread wheat improvement. The synthesis of Triticum turgidum–T. monococcum amphiploids is an essential step for transferring genes from T. monococcum into bread wheat. In this study, 264 wide hybridization combinations were done by crossing 60 T. turgidum lines belonging to five subspecies with 83 T. monococcum accessions. Without embryo rescue and hormone treatment, from the 10,810 florets pollinated, 1983 seeds were obtained, with a mean crossability of 18.34% (range 0–89.29%). Many hybrid seeds (90.73%, 923/1017) could germinate and produce plants. A total of 56 new amphiploids (AABBAmAm) were produced by colchicine treatment of T. turgidum × T. monococcum F1 hybrids. The chromosome constitution of amphiploids was characterized by fluorescence in situ hybridization using oligonucleotides probes with different chromosome and sub-chromosome specificities. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis indicated that the Glu-A1m-b, Glu-A1m-c, Glu-A1m-d and Glu-A1m-h proteins of T. monococcum were expressed in some amphiploids. Despite resistance reduction in several cases, 45 out of 56 amphiploids exhibited resistance to the current predominant Chinese stripe rust races at both the seedling and adult plant stage. These novel amphiploids provide new germplasm for the potential improvement of bread wheat quality and stripe rust resistance.

Shortawn foxtail (Alopecurus aequalis Sobol.) is an invasive and highly troublesome weed species originating from North America that has become widespread across China. Since its proliferation seriously threatens crop production worldwide, understanding its genetic diversity is critical for developing a forecasting system for integrated pest management plans. To accelerate the application of molecular markers in A. aequalis, this study aimed to develop a set of expressed sequence tag-simple sequence repeat (SSR) markers using previous high-throughput sequencing data. In this study, a total of 1411 SSR loci were identified from 95,479 unigenes. Tri-nucleotide repeat motifs were the most abundant type with a frequency of 66.27%, followed by di- (24.95%) and tetra-nucleotide (8.78%). Among the loci, 584 primer pairs were successfully designed for marker development. Subsequently, a subset of 36 primer pairs was randomly selected and synthesized, of which 12 (33.33%) pairs successfully revealed abundant allelic polymorphism. Additionally, to investigate their utility, the genotypes of 160 individuals from 20 natural populations representing diverse wild genotypes of A. aequalis were analysed by using these 12 polymorphic markers. These novel SSR markers developed here are reliable and useful for genetic analysis on this invasive plant and will greatly enrich its genetic resource.

Cinnamomum camphora (Lauraceae) is a well-known multipurpose tree with aromatic oils, insect-repellent effects and ornamental value. In this study, a total of 74,289 simple sequence repeats (SSRs) were found in 56,124 unigenes, of which 14,225 unigenes contained more than one SSR locus. Among these SSR loci, the mono-nucleotide repeats were the most frequent, with a frequency of 61.14%, followed by 24.87% di-nucleotide repeats and 12.87% tri-nucleotide repeats. Twenty-one polymorphic SSR markers were developed and validated in 45 camphor trees. The 21 loci were further examined for cross-species transferability in other six related species. The novel genic-SSR markers will not only benefit genetic diversity analysis and wild resources conservation of C. camphora, but also contribute to exploring the further evolutionary history and genetic differentiation pattern of Cinnamomum.

We developed novel and polymorphic microsatellite primers for Spathoglottis plicata, a tropical and subtropical terrestrial orchid, to investigate the genetic patterns and population structure among wild populations, and also to identify the varieties and hybrids of S. plicata in horticultural industry. The 12 novel microsatellites from S. plicata were developed by using polymerase chain reaction (PCR)-based isolation of microsatellite arrays. These markers that were successfully PCR amplified exhibited polymorphisms in S. plicata. The number of alleles, observed heterozygosity, expected heterozygosity and polymorphism information content values across loci ranged from 2.000 to 8.000, 0.000 to 0.756, 0.208 to 0.813 and 0.405 to 0.805 in total populations, respectively. The newly developed microsatellite markers exhibited variation in S. plicata. These markers can be used as a tool to further investigate the genetic diversity, conservation genetics and variety/hybrid identification of S. plicata.