Search Results (54)

Background: Seed shattering enhances ecological adaptation in perennial grasses but severely limits harvestable seed yield in forage crops. Psathyrostachys juncea is an important perennial forage species in arid and cold regions, yet the genetic basis of its seed shattering remains largely unknown. Here we asked which genomic regions and biological pathways underlie natural variation in seed shattering in P. juncea, and whether cellulose synthase (CESA)-mediated cell-wall formation contributes to abscission-zone strength. Results: We evaluated seed shattering in a diverse association panel of P. juncea across four environment–-year combinations and performed a genome-wide association study (GWAS) using genotyping-by-sequencing single-nucleotide polymorphism (SNP) markers. The analysis identified 36 significant SNP loci distributed on multiple chromosomes, consistent with a highly polygenic and environment-responsive architecture. Candidate-gene annotation highlighted pathways related to cell-wall biosynthesis, hormone signaling and sugar transport. Notably, in the BT23SHT environment a cluster of association signals on chromosome 3D co-localized with several genes annotated as cellulose synthase (CESA). Abscission-zone transcriptome profiling and qRT-PCR at 7, 14, 21 and 28 days after heading revealed that CESA genes, including TraesCS3D02G010100.1 located near the lead SNP Chr3D_3539055, showed higher early expression in low-shattering lines and a decline toward baseline in high-shattering lines. Comparative analyses placed P. juncea CESA proteins within a broadly conserved but lineage-divergent framework among grasses. Conclusion: Together, these results define the genetic landscape of seed shattering in P. juncea and nominate cellulose-biosynthetic genes on chromosome 3D as promising targets for marker-assisted selection of low-shattering, high-seed-yield forage cultivars. Full article

Thinopyrum intermedium (c.n. intermediate wheatgrass), marketed under the trade name Kernza, is a promising species for perennial grain production based on seed size, ease of threshing, resistance to shattering, and grain quality. Although numerous generations of breeding for seed yield have been completed, the impact of selection on non-target traits is unknown. Here, we evaluated structural and functional changes brought about by selection for seed yield over a sequence of nine selection cycles (C0 to C9). In two experiments under semi-controlled environmental conditions, we compared gas exchange (A, E, gs, and A/Ci curves), leaf and root morphology, and the structure of seedlings from 10 generations. We found that the selection for yield throughout cycles indirectly changed the leaf structure (leaf size, leaf thickness, and leaf anatomy) and physiology (carbon acquisition and transpiration per unit area), with later cycles showing larger leaves with higher rates of CO₂ assimilation and transpiration. Changes in root structure followed similar trends: selection resulted in longer, more branched, and finer roots. These changes in non-target traits are linked to resource-use strategies and to ecosystem services provided by Kernza. Understanding how the domestication of perennial grains impacts non-target traits will aid in the design of integrated breeding programs for Kernza and other perennial grain crops. Full article

Weedy rice (Oryza spp.) has become one of the most harmful weeds in rice fields worldwide. It is a conspecific plant of cultivated rice (Oryza sativa L.) belonging to the genus Oryza, widely occurring in global rice production systems with a cosmopolitan distribution across major rice-growing regions. Due to its unique biological characteristics, such as strong environmental adaptability, stress resistance, seed shattering propensity, seed dormancy, and competitive dominance, weedy rice can rapidly proliferate and persist in fields, posing a severe threat to rice production systems. This review summarizes the current research progress on the biological characteristics of weedy rice and introduces the significant differences in biological characteristics between weedy and cultivated rice, such as phenotypic diversity, seed shattering, dormancy, strong competitiveness, stress resistance, and early maturity. These distinct biological traits, which significantly differ from cultivated rice, serve as essential mechanisms in the survival strategy of weedy rice. Our review will provide a theoretical reference for a deeper understanding of weedy rice and its integrated management. Full article

Silique dehiscence is a critical biological phenomenon in rapeseed production that significantly influences seed maturity, harvesting efficiency, and ultimately yield. As one of the world’s most important oilseed crops, studying the mechanisms underlying silique dehiscence in rapeseed (Brassica napus L.) not only aids in understanding fundamental principles of plant development but also provides a scientific basis for optimizing agricultural production practices. Silique dehiscence occurs naturally during the maturation process of rapeseed, with the timing and extent of this phenomenon directly affecting seed harvesting efficiency. This paper reviews the research progress regarding the mechanization of canola production, which enhances harvesting efficiency by enabling timely harvest coordination to minimize pre-harvest shattering losses and reduce post-harvest seed damage. Additionally, it addresses the factors influencing pod shattering, the process of pod shattering, the genes associated with this phenomenon, and the molecular mechanisms underlying pod shattering. These findings establish a foundation for a comprehensive understanding of pod shattering in canola. Full article

The continued emergence of weedy rice (Oryza sativa L.) in Taiwan poses serious challenges to seed purity and commercial rice cultivation, particularly under transplanting systems. These off-type individuals, often marked by a red pericarp, reduce varietal integrity and complicate seed propagation. This study evaluated the morphological variation among 117 Taiwan weedy rice (TWR) accessions and 55 control cultivars, which include 24 temperate japonica cultivars (TEJ), 24 indica cultivars, and seven U.S. weedy rice (UWR) types. Principal component analysis (PCA) showed that TWR shares vegetative traits with modern cultivars but exhibits grain morphology resembling indica landraces—indicating weak artificial selection pressure on grain traits during nursery propagation. TWR was also found to possess a suite of adaptive weedy traits, including semi-dwarfism, delayed heading, high shattering, and superior seed storability, facilitating its persistence in field conditions. These findings provide critical insights for integrated weed management and cultivar purity strategies, emphasizing the importance of certified seed use, stringent field hygiene, and disruption of weedy rice reproductive cycles. Full article

Niger (Guizotia abyssinica (L. f.) Cass.), an oilseed crop from the Compositae family, thrives in temperate and tropical climates. Its small seeds, rich in oil (50–60% biocrude), are widely used for biodiesel, soap production, and as a condiment in culinary applications. Additionally, harvested Niger plants serve as green manure, improving soil health. However, Niger cultivation in India has significantly declined over the past decade due to low yields, a poor seed set, self-incompatibility, a low harvest index, and seed shattering. A lack of genetic diversity further restricts breeders from developing high-yielding cultivars. The discovery of hereditary male sterility in India has facilitated heterosis utilization and laid the foundation for breeding improved varieties. This review explores the use of traditional breeding methods and genetic tools to enhance Niger, emphasizing plant tissue culture, molecular markers, and the identification of promising gene targets to produce desirable traits. Advanced technologies like CRISPR/Cas, including base and prime editing, are promising to revolutionize Niger breeding and functional genomics research. The insights in this paper stress the urgent need to genetically improve Niger and other underutilized oil crops to meet the increasing global demand for sustainable and diverse oil crops. Such interventions could transform Niger cultivation, ensuring its role in global agriculture. Full article

Lotus, with about 120 species, is the largest genus of Leguminosae–Loteae. The last global classification recognized 14 sections, of which 13 were then sampled in molecular phylogenetic analyses. The section remaining unsampled is Lotus sect. Benedictella with one critically endangered and possibly extinct species, L. benoistii. This is an annual species known from Mediterranean-type vernal pools in the lowlands of northwestern Morocco that differs from other species of the genus in many-seeded indehiscent fruits with thin pericarp and pinnate leaves with 6–9 leaflets. This species was described in a monospecific genus and later transferred to Lotus on the basis of suggested morphological similarities with three mainly desert annuals from North Africa and Southwest Asia currently classified in Lotus sect. Chamaelotus. We provide the first molecular phylogenetic data on L. benoistii and show that it is far from L. sect. Chamaelotus. It is close to plants traditionally classified in Lotus sect. Lotus that have a center of diversity in Europe and temperate Asia. Phylogenetic analyses of plastid markers showed that L. sect. Chamaelotus belongs to a clade with major taxonomic diversity in Macaronesia, Africa, SW Asia, and Australia. Morphology does not provide arguments against the novel hypothesis on the relationships of L. benoistii. Its possible extinction is a great loss for the breeding programs of the pasture plant L. corniculatus. We provide the first anatomical data of L. benoistii, showing that its non-shattering condition has a peculiar nature that differs from all other instances of indehiscence in Loteae. Full article

Seed shattering (SS) functions are a survival mechanism in plants, enabling them to withstand adverse environmental conditions and ensure reproduction. However, this trait limits seed yield. Psathyrostachys juncea, a perennial forage grass with many favorable traits, is constrained by SS, limiting its broader application. To investigate the mechanisms underlying SS, second-generation Illumina sequencing and third-generation PacBio sequencing were conducted on abscission zone tissues of P. juncea at 7, 14, 21, and 28 days after heading. GO enrichment analysis identified several significant biological processes, including the “cell wall macromolecule catabolic process”, “cell wall polysaccharide catabolic process”, “hemicellulose catabolic process”, and “xylan catabolic process”, all involved in cell wall degradation. KEGG enrichment analysis showed that differentially expressed genes were predominantly enriched in pathways related to “starch and sucrose metabolism”, “fructose and mannose metabolism”, “phenylpropanoid biosynthesis”, “pentose and glucuronate interconversions”, and “galactose metabolism”, each linked to both the synthesis and degradation of the cell wall. Further analysis of the “starch and sucrose metabolism” pathway revealed genes encoding fructokinase, hexokinase, β-glucosidase, sucrose phosphate synthase, sucrose synthase, and endoglucanase, all of which affected cellulose content. Reduced cellulose content can alter cell wall structure, leading to SS. These findings provide new insights into the regulation of SS in P. juncea and offer valuable references for other species within the Poaceae family. Full article

Sesame seeds and their edible oil are highly nutritious and rich in mono- and polyunsaturated fatty acids. Bioactive compounds such as sterols, tocopherols, and sesamol provide significant medicinal benefits. The high oil content (50%) and favorable mono- and polyunsaturated fatty acid balance, as well as resilience to water stress, make sesame a promising candidate crop for global agricultural expansion. However, sesame production faces challenges such as low yields, poor response to agricultural inputs, and losses due to capsule dehiscence. To enhance yield, traits like determinate growth, dwarfism, a high harvest index, non-shattering capsules, disease resistance, and photoperiod sensitivity are needed. These traits can be achieved through variation or induced mutation breeding. Crossbreeding methods often result in unwanted genetic changes. The gene editing CRISPR/Cas9 technology has the potential to suppress detrimental alleles and improve the fatty acid profile by inhibiting polyunsaturated fatty acid biosynthesis. Even though sesame is an orphan crop, it has entered the genomic era, with available sequences assisting molecular breeding efforts. This progress aids in associating single-nucleotide polymorphisms (SNPs) and simple sequence repeats (SSR) with key economic traits, as well as identifying genes related to adaptability, oil production, fatty acid synthesis, and photosynthesis. Additionally, transcriptomic research can reveal genes involved in abiotic stress responses and adaptation to diverse climates. The mapping of quantitative trait loci (QTL) can identify loci linked to key traits such as capsule size, seed count per capsule, and capsule number per plant. This article reviews recent advances in sesame breeding, discusses ongoing challenges, and explores potential strategies for future improvement. Hence, integrating advanced genomic tools and breeding strategies provides promising ways to enhance sesame production to meet global demands. Full article

Perennial warm-season grasses typically have reduced seed yield, making it essential to identify the critical seed yield components. An induced increase in nitrogen could help determine which components are most limiting. This research aimed to estimate seed yield components in Paspalum; evaluate N fertilization effects on the reproductive phase, seed yield components, and seed quality; and establish the pattern of seed shattering over time. Nine genotypes covering different reproductive periods were used. The experimental design was a randomized complete block design in a split-plot arrangement with three replications. The main plots had two nitrogen levels (0 and 150 Kg N ha⁻¹), and the sub-plots contained different genotypes. Seed yield variation was mainly related to reproductive tiller density among germplasm with different flowering periods. Early-flowering germplasm showed an extended flowering period (159%), greater tiller density (27.7%), greater reproductive tiller density (157%), and higher yield (302%) in response to nitrogen fertilization. Seed-quality traits and seed retention were not affected by nitrogen fertilization. Seed retention over time followed an inverted sigmoid pattern, though there was considerable variation among taxonomic groups. Early-flowering germplasm exhibited superior seed retention. Seed yield in Paspalum is mainly influenced by the density of reproductive tillers and seed retention. Full article

Rapeseed siliques easily shatter after ripening, resulting in a significant amount of grain loss, which delimits the development of rapeseed machine harvest. However, the effect of nitrogen (N) and density interaction on the characteristics of rape siliques and shattering resistance index is still vague. During the 2021–2022 and 2022–2023 growing seasons, we selected the Jiayou No. 5 rapeseed variety and set three N application levels (N1: 90 kg ha⁻¹, N2: 180 kg ha⁻¹, N3: 270 kg ha⁻¹) and two density treatments (M1: 150,000 plants ha⁻¹, M2: 300,000 plants ha⁻¹) to research the effects of N and density interaction on morphological indexes, physiological indexes, shatter resistance index and yield of direct-seeding rapeseed siliques. The silique shatter resistance index, silique’s length, weight, moisture content, silique shell’s weight, thickness, lignin content, cellulose content and phenylalaninase (PAL) activity all increased first and then decreased with the increase in the N application rate; the N2 treatment increased by 18.38% and 26.92%, respectively, compared to the N1 and N3 treatments; 3.65%, 2.48%; 6.70%, 3.58%; 20.46%, 18.33%; 5.97%, 5.96%; 8.82%, 9.60%; 9.12%, 19.90%; 43.85%, 69%; 2.10%, 11.04%. Compared with the M1 treatment, the silique shatter resistance index, silique’s length, weight, moisture content, silique shell’s weight, thickness, lignin content, cellulose content and PAL activity were lower under M2 treatment. Correlation analysis demonstrated that the silique’s length, water content, silique shell’s weight, thickness, lignin content, cellulose content and PAL activity were significantly positively correlated with the silique shatter resistance index. Therefore, this study shows that N2M1 treatment can carry off synergy between silique shatter resistance and yield. Full article

Weedy rice (Oryza sativa f. spontanea) is a noxious weed infesting rice fields worldwide and causes great yield losses for cultivated rice. Effective management of this weed is essential for the world’s rice production. Yet, the management of weedy rice is challenging. One of the reasons is that shattered weedy rice seeds stored in soil often trigger great weed proliferation in the succeeding crop seasons. To study the survival of weedy rice seeds in soil seedbanks, we conducted 90-day soil burial experiments at different soil depths from 0–25 cm, using weedy rice seeds from Jiangsu Province in China. Results from two independent experiments under the rice field and laboratory conditions indicated significant differences in seed death ratios (SDRs) and induced seed dormancy ratios (ISDRs) of weedy rice at different soil burial depths. Weedy rice seeds exposed to the soil surface (0 cm burial treatment) had the highest SDRs and lowest ISDRs. An evident pattern of quickly declining SDRs with increased soil burial depths was identified from this study, suggesting rapid losses of seed viability on the surface and in shallow layers of soil. Our findings provide a useful guide for designing strategies to effectively control weedy rice by maintaining shattered seeds on the surface or in shallow layers of soil. The practices can easily be achieved through adopting the no-till farming system, which can substantially minimize viable weedy rice seeds as an important component in comprehensive weed management strategies. Full article

Seed shattering is an adaptive feature of seed dispersal in wild rice, and it is also an important agronomic trait affecting yield. Reduced seed shattering was a significant progress during rice domestication. However, the evolutionary pathway and molecular mechanism of hybrid seed shattering remain largely unknown. In order to gain a deeper understanding of the regulation of hybrid seed shattering, HS4, a locus conferring hybrid seed shattering between Oryza sativa and Oryza glaberrima, was identified and fine mapped to a 13.5-kb genomic region containing two putative genes during the development of chromosomal segment substitution lines (CSSLs). Expression analysis indicated that the hybrid seed shattering was not related to the expression of HS4. Preliminary research on the molecular mechanism of HS4-mediated hybrid seed shattering indicated that HS4^HJX74 and HS4^HP61 may form a multimer in heterozygotes, achieving the original function of a trihelix transcription factor through protein interaction. The identification and characterization of HS4 in this study not only provides new insights into the molecular mechanisms underlying hybrid seed shattering, but also provides a potential target for genome editing to reduce the difficulty of hybridization between the two species, facilitating hybrid breeding and increasing yield in rice. Full article

Flaxseed has gained popularity as a health food. Wild, perennial Linum relatives of annual flax (L. usitatissimum) possess similar oil compositions, making them perennial oilseed (OS) alternatives. The objective of this study was to phenotype 25 OS and 17 cut flower (CF) breeding populations with 137 wild Linum species’ accessions in a common garden over three years (Y1–3) to quantify the impact of selection and identify top candidates. This study was intercepted by COVID-19, which prevented the same detailed phenotyping of Y1 from occurring in Y2–3. Traits measured from the perennial flax OS, in comparison with the CF ideotypes: weekly seed germination (Y1), yield per plant (Y1–3), seed weight (Y1–2), shattering (Y1–2), and seed capsule diameter (Y1). In Y1, OS selections had the highest yield per plant, followed by L. austriacum and then CF selections. The 1000 seed weights in Y1 were highest in annual flax, followed by L. grandiflorum and L. baicalense. Seed numbers/capsule were low in Y1–2, possibly due to shattering. Average yield per plant increased across Y1–3 indicating that, once plant establishment had occurred along with the potential for two harvests/year in Y2 onwards, significant OS yield can be realized. Harvest 1 yields were significantly higher than in harvest 2. In Y1–3, OS selections had the highest average seed yield. In Y1, OS and CF populations had smaller seeds, higher shattering, smaller capsule diameters, and lower germination than wild species. Significant breeding efforts are needed to increase perennial flax yield, using the multiple crop ideotypes. Full article

In plants, an increasing number of traits and new characteristics are being developed using gene editing. Simple traits represented by a single gene can be managed through backcross breeding, but this is typically not the case for more complex traits which may result from the function of a large number of genes. Here, we demonstrate two case studies of improving oleic oil content and developing pod shatter reduction in Brassica napus by using gene editing tools on an industrial scale. There are four BnaFAD2 genes involved in oleic oil content and eight BnaSHP genes involved in pod shatter tolerance. In order to develop these two traits, we delivered nuclease ribonucleoproteins with Gene Repair OligoNucleotides (GRONs) into protoplasts, with subsequent regeneration into plants on an industrial scale, which encompassed robust tissue culture protocols, efficient gene editing, robotics sampling, and molecular screening, vigorous plant regeneration, growth, and phenotyping. We can produce precise loss-of-function-edited plants with two improved agronomically important complex traits, high oleic oil or pod shatter reduction, in elite canola varieties within 1–3 years, depending on the trait complexity. In the edited plants carrying loss of function of four BnaFAD2 genes, the seed fatty acid oleic acid content reached 89% compared to 61% in the non-edited wildtype control. The plants carrying eight edited BnaSHP genes achieved 51% pod shatter reduction in multiple year field testing in the target environment compared to the wildtype control. Full article