Photoperiod Sensitivity Research Articles

Post-Flowering Photoperiod Sensitivity of Soybean in Pod-Setting Responses

The development of soybean (Glycine max) is regulated by the photoperiod, with genes related to photoperiod sensitivity primarily focused on the flowering time. However, their roles in post-flowering reproductive development and the mechanisms by which the photoperiod affects them are not yet determined. In this study, we found that pod formation is sensitive to the photoperiod. Long-day conditions tended to extend the time from flowering to pod formation, and the first wave of flowers tended to fall off. Additionally, the photoperiod affected the pistil morphology; under short-day conditions, the stigma had a curved hook-like structure that facilitated better interaction with the filaments when pollen was released, ultimately influencing the timing of pod formation. Photoperiod-insensitive mutants, lacking E1 family and Evening Complex (EC) genes, showed no difference in the pod formation time under long-day or short-day conditions. Hormone content analysis and transcriptome data analysis indicated that various hormones, reactive oxygen species (ROS) burst pathway signals, and the application of sucrose solution in vitro might influence floral organ abscission.

Early Flowering and Maturity Promote the Successful Adaptation and High Yield of Quinoa (Chenopodium quinoa Willd.) in Temperate Regions

Quinoa (Chenopodium quinoa Willd.) can offer an alternative for staple food considering its tolerance to abiotic stresses and high seed quality. However, its cultivation in temperate regions has not been successful due to its photoperiod sensitivity and low seed yield. This study investigated the agronomical performance and quality traits of 48 accessions for cultivation in northern Europe. We conducted two-year field trials and phenotyped traits related to phenological development, plant architecture, yield components, seed quality, and disease resistance. The major determinants of seed yield in this study were days to flowering, days to maturity, thousand-kernel weight, and panicle density, while downy mildew susceptibility and stem lodging showed a negative correlation with seed yield. We developed a selection index to enable simultaneous selection based on different important agronomical traits. We evaluated the stability of different accessions over the two years of the experiment. Finally, we provided a list of 10 selected accessions that can be directly integrated and serve as new crossing parents in quinoa breeding programs for temperate regions.

The prospects for the introduction of a mesoamerican species chia Salvia hispanica L. in the conditions of the southern forest-steppe of Western Siberia

Relevance. This article presents the results of breeding work and the introduction of the Mesoamerican culture Spanish sage or chia (Salvia hispanica L.), which is currently one of the most popular pseudo-grain crops from the family of Lamiaceae in Western countries due to its unique seeds rich in nutrients, PUFA, dietary fiber and antioxidants. In 2009, the European Union considered the seeds of the plant to be a promising type of food. There are only 17 registered genotypes of culture in the world, in the collection of GRR VIR there are two forms obtained from European countries. There are no registered varieties of Spanish sage in the state register of breeding achievements approved for use in the territory of the Russian Federation. The research of this culture is limited only by the biological side: the study of morphobiological features, its use for decorative purposes.Material and methodology. The research was conducted in the educational and experimental farm of the Omsk State Agrarian University in 2019-2023. The objects of research were several samples of various ecological and geographical origin and 2 new forms of Spanish sage obtained during local selection. All records and observations were carried out according to the following methods: field experience in vegetable growing (S.S. Litvinov, 2011), State variety testing of agricultural crops (1989), assessment of primary introduction by G.P. Semenova (2001) and variety assessment of floral ornamental plants by V.N. Bylov (1971).Results. As a result of continuous year-round introduction work, the breeders of the Omsk State Agricultural University managed to overcome the photoperiodic sensitivity of the plant and obtain adaptive forms 0/18 and 3/18. An assessment of the decorative value, the success of the introduction and the possibility of introducing new samples into production in the conditions of the southern forest-steppe of Western Siberia is given. The first of the locally obtained forms, as more productive, was transferred to the state variety testing in 2023 under the assumed name of the variety "Siberian Emerald". Breeding work in this direction continues.

Sesame, an Underutilized Oil Seed Crop: Breeding Achievements and Future Challenges.

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.

Integrated GWAS, linkage, and transcriptome analysis to identify genetic loci and candidate genes for photoperiod sensitivity in maize.

Maize photosensitivity and the control of flowering not only are important for reproduction, but also play pivotal roles in the processes of domestication and environmental adaptation, especially involving the utilization strategy of tropical maize in high-latitude regions. In this study, we used a linkage mapping population and an inbred association panel with the photoperiod sensitivity index (PSI) phenotyped under different environments and performed transcriptome analysis of T32 and QR273 between long-day and short-day conditions. The results showed that PSIs of days to tasseling (DTT), days to pollen shedding (DTP), and days to silking (DTS) indicated efficacious interactions with photoperiod sensitivity for maize latitude adaptation. A total of 48 quantitative trait loci (QTLs) and 252 quantitative trait nucleotides (QTNs) were detected using the linkage population and the inbred association panel. Thirteen candidate genes were identified by combining the genome-wide association study (GWAS) approach, linkage analysis, and transcriptome analysis, wherein five critical candidate genes, MYB163, bif1, burp8, CADR3, and Zm00001d050238, were significantly associated with photoperiod sensitivity. These results would provide much more abundant theoretical proofs to reveal the genetic basis of photoperiod sensitivity, which would be helpful to understand the genetic changes during domestication and improvement and contribute to reducing the barriers to use of tropical germplasm.

Genes of photoperiod sensitivity and early maturity E1-E4: dynamics of soybean growth in different daylength conditions

Background. Morphometric indicators are crucial for evaluating the development and productivity of soybeans. They are influenced by genetic and environmental factors. The use of nearly isogenic soybean lines is a convenient model for determining the impact of early maturity genes and daylength on growth indicators. The aim of this study was to determine the influence of different daylengths and early maturity genes on soybean morphometric indicators under conditions of the temperate zone (at the latitude of Kharkiv – 50° N). Materials and Methods. The study involved nearly isogenic soybean lines of the “Clark” cultivar with varying sensitivity to daylength. The research covers the results of field experiments over three seasons using different soybean lines. After reaching the V3 stage, some plants were subjected to short-day conditions for 14 days. Morphological indicators of ten plants per experimental variant were determined: plant height, dry weight, leaf number, and leaf surface area of soybean plants. Morphometric measurements were taken on the day of the beginning of different daylength treatments and on days 7, 14 and 21. The study results are presented as the mean values of the investigated parameters (plant height, dry weight, number of leaves and leaf surface area of soybean plants). Results. It was shown that under long-day conditions, dominant alleles of the E1 and E3 genes increased the dry weight of plants, while the dominant allele E2 increased plant height. The dominant allele E4 had no significant effect on plant height and weight indicators of soybean plants. Plants with dominant alleles of genes E1-E4 under long-day conditions had smaller leaf area compared to lines with recessive alleles of these genes. Conclusions. The obtained results on the relationships between genetic and environmental factors in influencing soybean plant height, weight, and leaf area can be useful in improving soybean yield and selecting cultivars that will be productive in high latitude conditions.

Stable early heading in photoperiod-insensitive rice varieties results from an extremely short photoperiod-sensitive phase and weak temperature sensitivity

The transition from vegetative to reproductive growth in rice (Oryza sativa) is mainly regulated by photoperiod and temperature; however, it remains unclear how photoperiod-insensitive (photo-In) early heading rice varieties make this transition. Vegetative growth consists of a basic vegetative phase (BVP) and a photoperiod-sensitive phase (PSP). A certain duration of the BVP is required prior to the PSP, which varies according to daylength conditions. PSP duration is conventionally used as a parameter of photoperiod sensitivity, but this is not applicable to photo-In rice varieties. Here, we aimed to characterize the PSP in photo-In rice varieties. We examined four photo-In varieties and photoperiod-sensitive (photo-Se) varieties grown in four controlled environments, evaluating the lengths of their growth phases based on the turning point of the interval of leaf emergence and panicle initiation (PI). The photo-In varieties had an extremely short PSP, regardless of daylength, compared with the photo-Se varieties. Low temperature uniformly prolonged all growth stages in the photo-In varieties but led to a much longer PSP in the photo-Se varieties. The photo-In varieties, each carrying a non-functional allele of Ghd7, lost the ability to suppress PI, resulting in early heading. Hemi-knockout plants at the Ghd7 locus demonstrated the earlier heading than the wild-type plant due to shortening of PSP. Our results suggest that the photo-In varieties begin PI immediately after the end of the BVP, but their flowering is not a temperature-dependent process.

OsCKq1 Regulates Heading Date and Grain Weight in Rice in Response to Day Length

BackgroundPhotoperiod sensitivity is among the most important agronomic traits of rice, as it determines local and seasonal adaptability and plays pivotal roles in determining yield and other key agronomic characteristics. By controlling the photoperiod, early-maturing rice can be cultivated to shorten the breeding cycle, thereby reducing the risk of yield losses due to unpredictable climate change. Furthermore, early-maturing and high-yielding rice needs to be developed to ensure food security for a rapidly growing population. Early-maturing and high-yielding rice should be developed to fulfill these requirements. OsCKq1 encodes the casein kinase1 protein in rice. OsCKq1 is a gene that is activated by photophosphorylation when Ghd7, which suppresses flowering under long-day conditions, is activated.ResultsThis study investigates how OsCKq1 affects heading in rice. OsCKq1-GE rice was analyzed the function of OsCKq1 was investigated by comparing the expression levels of genes related to flowering regulation. The heading date of OsCKq1-GE lines was earlier (by about 3 to 5 days) than that of Ilmi (a rice cultivar, Oryza sativa spp. japonica), and the grain length, grain width, 1,000-grain weight, and yield increased compared to Ilmi. Furthermore, the culm and panicle lengths of OsCKq1-GE lines were either equal to or longer than those of Ilmi.ConclusionsOur research demonstrates that OsCKq1 plays a pivotal role in regulating rice yield and photoperiod sensitivity. Specifically, under long-day conditions, OsCKq1-GE rice exhibited reduced OsCKq1 mRNA levels alongside increased mRNA levels of Hd3a, Ehd1, and RFT1, genes known for promoting flowering, leading to earlier heading compared to Ilmi. Moreover, we observed an increase in seed size. These findings underscore OsCKq1 as a promising target for developing early-maturing and high-yielding rice cultivars, highlighting the potential of CRISPR/Cas9 technology in enhancing crop traits.

N6-methyladenosine RNA modification regulates photoperiod sensitivity in cotton.

The methylation of N6-methyladenosine (m6A) involves writers, erasers, and readers, acting synergistically in posttranscriptional regulation. These processes influence various biological processes, including plant floral transition. However, the specific role of m6A modifications in photoperiod sensitivity in cotton (Gossypium hirsutum) remains obscure. To elucidate this, in this study, we conducted transcriptome-wide m6A sequencing during critical flowering transition stages in the photoperiod-sensitive wild G. hirsutum var. yucatanense (yucatanense) and the photoperiod-insensitive cultivated cotton G. hirsutum acc. TM-1 (TM-1). Our results revealed significant variations in m6A methylation of 2 cotton varieties, with yucatanense exhibiting elevated m6A modification levels compared with TM-1 under long-day conditions. Notably, distinct m6A peaks between TM-1 and yucatanense correlated significantly with photoperiod sensitivity. Moreover, our study highlighted the role of the demethylase G. hirsutum ALKB homolog 5 (GhALKBH5) in modulating m6A modification levels. Silencing GhALKBH5 led to a decreased mRNA level of key photoperiodic flowering genes (GhADO3, GhAGL24, and GhFT1), resulting in delayed bud emergence and flowering. Reverse transcription quantitative PCR analyses confirmed that silencing GhADO3 and GhAGL24 significantly downregulated the expression of the floral integrator GhFT1. Collectively, our findings unveiled a transcriptional regulatory mechanism in which GhALKBH5-mediated m6A demethylation of crucial photoperiodic flowering transcripts modulated photoperiod sensitivity in cotton.

Species that require long day conditions to flower are not advancing their flowering phenology as fast as species without photoperiod requirements.

Over the last few decades, many plant species have shown changes in phenology, such as the date on which they germinate, bud or flower. However, some species are changing slower than others, potentially due to daylength (photoperiod) requirements. We combined data on flowering time advancement with published records of photoperiod sensitivity to try to predict which species are advancing their flowering time. Data availability limited us to the Northern Hemisphere. Cross-species analyses showed that short day plants advanced their flowering time by 1.4 days per decade, day neutral plants advanced by 0.9 days per decade, but long day plants delayed their flowering by 0.2 days per decade. However, photoperiod sensitivity status was moderately phylogenetically conserved, and the differences in flowering time advancement were not significant after phylogeny was accounted for. Both annual and perennial herbs were more likely to have long day photoperiod cues than woody species, which were instead more likely to have short day photoperiod cues. Short day plants are keeping up with plants that do not have photoperiod requirements, suggesting that daylength requirements do not hinder changes in phenology. However, long day plants are not changing their phenology and may risk falling behind as competitors and pollinators adapt to climate change.

Использование молекулярно-генетических маркеров для идентификации генов чувствительности к фотопериоду в селекционном материале сои

Soybean is one of the important oil and forage crops. It contains large amounts of oil, protein, vitamins, and other valuable nutrients. Annually, sowing area under soybean in Russia enlarges towards central and Siberian regions. However, soybean is very sensitive to photoperiod that is a key factor in regulation of soybean growth and development. The identification of gens controlling a photoperiodic sensitivity in soybeans is important for breeding of new adaptive cultivars. DNA-markers are an effective instrument for the selection of valuable genotypes from breeding germplasm. In this work, we identified gens contributing the most of decrease in soybean sensitivity to a day length. There were estimated six cultivars, five lines F6–F7, and five hybrids F1 of soybean. We used six molecular markers. Due to results, the early maturing cultivars Elana and Barguzin had the largest amount of recessive alleles; the cultivar Mamont had the largest amount of dominant alleles that characterizes it as middle maturing. The rest samples had two or three recessive alleles and belong to maturity groups from early to middle early. The analysis of hybrid combinations showed that a molecular marker for a Е3-gen is inherited co-dominantly. This allowed using it to control transferring of desired gens at crosses in progeny. Thus, the usage of the molecular-genetic markers was effective in selection by a studied trait and can be used in the breeding process.

Повышение эффективности селекции сои с пониженной реакцией на длину дня на примере сорта Липчанка

A very early maturing soybean cultivar Lipchanka with a reduced response on a day length was isolated from the hybrid combination F4 D-12/14 × L-247 by traits of productivity, cold resistance, photoperiodic sensitivity, and the morphotype of the flower ovary style. The Lipchanka variety belongs to a very early maturity group, at the latitude of Krasnodar (45°) it ripens in 95 days, and in terms of yield exceeds the standard cultivar Barguzin by an average of 0.11 t/ha. In a competitive variety testing in Krasnodar in 2021–2023 its yield was 1.32–3.19 t/ha. In a competitive variety trial in Lipetsk at a latitude of 52°, the duration of the growing season of this cultivar averaged 105 days with a yield of 2.41–2.67 t/ha, which exceeded the standard variety Barguzin by 0.09 t/ha. Under the conditions of the Kaluga region, at a latitude of 54°, the cultivar Lipchanka had a growing season of 113 days and successfully ripened until mid-September. The height of Lipchanka plants at the latitude of Krasnodar was 70–85 cm. In the Lipetsk region, the plant height of Lipchanka varied within 70–95 cm. In the conditions of the Kaluga region, the height of the cultivar Lipchanka was 71 cm. The new very early maturing soybean cultivar Lipchanka has reduced sensitivity to the range of day lengths formed at latitudes of 45–54°, high yield in the long-day conditions of the Central Black Earth region, and successful ripening in the conditions of the Central region of the Russian Federation. Such features of the cultivar allows to recommend it for cultivation in the Central, Volga-Vyatka, Central Black Earth, North Caucasus, Middle Volga, Lower Volga, Ural, and West Siberian regions of the Russian Federation.

Identification of Insertion/Deletion Markers for Photoperiod Sensitivity in Rice (Oryza sativa L.).

The current study aims to identify candidate insertion/deletion (INDEL) markers associated with photoperiod sensitivity (PS) in rice landraces from the Vietnamese Mekong Delta. The whole-genome sequencing of 20 accessions was conducted to analyze INDEL variations between two photoperiod-sensitivity groups. A total of 2240 INDELs were identified between the two photoperiod-sensitivity groups. The selection criteria included INDELs with insertions or deletions of at least 20 base pairs within the improved rice group. Six INDELs were discovered on chromosomes 01 (5 INDELs) and 6 (1 INDEL), and two genes were identified: LOC_Os01g23780 and LOC_Os01g36500. The gene LOC_Os01g23780, which may be involved in rice flowering, was identified in a 20 bp deletion on chromosome 01 from the improved rice accession group. A marker was devised for this gene, indicating a polymorphism rate of 20%. Remarkably, 20% of the materials comprised improved rice accessions. This INDEL marker could explain 100% of the observed distinctions. Further analysis of the mapping population demonstrated that an INDEL marker associated with the MADS-box gene on chromosome 01 was linked to photoperiod sensitivity. The F1 population displayed two bands across all hybrid individuals. The marker demonstrates efficacy in distinguishing improved rice accessions within the indica accessions. This study underscores the potential applicability of the INDEL marker in breeding strategies.

Is the time of anthesis in rice (Oryza sativa) influenced by photoperiod?

Photoperiod sensitivity in rice cultivars is defined when the cultivar begins anthesis on a relatively invariant date, varying by < 7days, regardless of the date of sowing or germination. While the date of flowering in photoperiod sensitive (PPS) rice cultivars is characteristically determined by the day length, especially during the short-day season (September-December), the response of the flower opening time (FOT) to photoperiod remains hitherto unexplored. This paper examines whether day length restrains year-to-year variation in FOT in PPS cultivars. We examined 105 PPS and 173 photoperiod insensitive (PPI) cultivars grown in different years and estimated their year-to-year FOT difference (or FOTD) and the year-to-year difference of sunrise to anthesis duration (or SADD). Wilcoxon signed rank test and bootstrap test were then performed to test whether these descriptors significantly differed between PPS and PPI groups of cultivars. The means of FOTD and SADD were detected to be significantly less in the PPS group than in the PPI group of cultivars, indicating significantly lesser variability of FOT in PPS than in PPI cultivars. This is the first report of a strong restraining influence of photoperiod on FOT variability in PPS cultivars.

A critical suppression feedback loop determines soybean photoperiod sensitivity

Photoperiod sensitivity is crucial for soybean flowering, adaptation, and yield. In soybean, photoperiod sensitivity centers around the evening complex (EC) that regulates the transcriptional level of the core transcription factor E1, thereby regulating flowering. However, little is known about the regulation of the activity of EC. Our study identifies how E2/GIGANTEA (GI) and its homologs modulate photoperiod sensitivity through interactions with the EC. During long days, E2 interacts with the blue-light receptor flavin-binding, kelch repeat, F box 1 (FKF1), leading to the degradation of J/ELF3, an EC component. EC also suppresses E2 expression by binding to its promoter. This interplay forms a photoperiod regulatory loop, maintaining sensitivity to photoperiod. Disruption of this loop leads to losing sensitivity, affecting soybean's adaptability and yield. Understanding this loop's dynamics is vital for molecular breeding to reduce soybean's photoperiod sensitivity and develop cultivars with better adaptability and higher yields, potentially leading to the creation of photoperiod-insensitive varieties for broader agricultural applications.

Fine mapping and targeted genomic analyses of photoperiod‐sensitive gene (GB_PPD1) in Pima cotton (Gossypium barbadense L.)

AbstractCotton grown in the United States are day‐length insensitive annuals and are grown under long‐day summers. Photoperiod sensitivity, present in tropical wild and landraces endemic to the center of origin and diversity, is a major barrier for the introgression of tropical gene pool into the US cotton. Previously, we mapped the major photoperiod response locus Gb_Ppd1 on chromosome D06 of Pima cotton (Gossypium barbadense L.). In the current study, an F2 population of 2112 gametes was used to fine map the Gb_Ppd1 locus. Two sequence‐tagged‐site and nine kompetitive allele‐specific polymerase chain reaction (KASP) markers were developed and the Gb_Ppd1 locus was fine mapped to 1.1 cM region flanked by novel markers 17‐KASP‐8, 17‐KASP‐10, and 15‐PR‐10A. The closely linked markers identified 2.10 Mb region in the G. barbadense genome that contained 18 putative gene sequences. A candidate gene Gbar_D06G014560 showed high homology to VASCULAR PLANT ONE ZINC FINGER PROTEIN 1 involved in photoperiodism in Arabidopsis. We evaluated the diagnostic polymorphisms for the flanking markers on a diversity panel of 91 Pima accessions. These markers would be useful in marker‐assisted selection of photoperiod response in cotton breeding. Further, quantitative gene expression analysis indicated that the CONSTANS (CO)/FLOWERING LOCUS T (FT) system is conserved in the photoperiod response pathway in Pima cotton, while CO and FT are likely not the causal genes underlying flowering time at the Gb_Ppd1 locus. The Gb_Ppd1 gene may be an upstream regulatory sequence in the FT gene pathway that controls photoperiodism in photoperiod‐sensitive cotton by affecting the CO/FT interaction under long‐day‐length conditions.

A FLOWERING LOCUS T ortholog is associated with photoperiod-insensitive flowering in hemp (Cannabis sativa L.).

Hemp (Cannabis sativa L.) is an extraordinarily versatile crop, with applications ranging from medicinal compounds to seed oil and fibre products. Cannabis sativa is a short-day plant, and its flowering is highly controlled by photoperiod. However, substantial genetic variation exists for photoperiod sensitivity in C. sativa, and photoperiod-insensitive ("autoflower") cultivars are available. Using a bi-parental mapping population and bulked segregant analysis, we identified Autoflower2, a 0.5 Mbp locus significantly associated with photoperiod-insensitive flowering in hemp. Autoflower2 contains an ortholog of the central flowering time regulator FLOWERING LOCUS T (FT) from Arabidopsis thaliana which we termed CsFT1. We identified extensive sequence divergence between alleles of CsFT1 from photoperiod-sensitive and insensitive cultivars of C. sativa, including a duplication of CsFT1 and sequence differences, especially in introns. Furthermore, we observed higher expression of one of the CsFT1 copies found in the photoperiod-insensitive cultivar. Genotyping of several mapping populations and a diversity panel confirmed a correlation between CsFT1 alleles and photoperiod response, affirming that at least two independent loci involved in the photoperiodic control of flowering, Autoflower1 and Autoflower2, exist in the C. sativa gene pool. This study reveals the multiple independent origins of photoperiod insensitivity in C. sativa, supporting the likelihood of a complex domestication history in this species. By integrating the genetic relaxation of photoperiod sensitivity into novel C. sativa cultivars, expansion to higher latitudes will be permitted, thus allowing the full potential of this versatile crop to be reached.

Dominance complementation of parental heading date alleles of Hd1, Ghd7, DTH8, and PRR37 confers transgressive late maturation in hybrid rice.

Rice (Oryza sativa L.) is a short-day plant whose heading date is largely determined by photoperiod sensitivity (PS). Many parental lines used in hybrid rice breeding have weak PS, but their F1 progenies have strong PS and exhibit an undesirable transgressive late-maturing phenotype. However, the genetic basis for this phenomenon is unclear. Therefore, effective methods are needed for selecting parents to create F1 hybrid varieties with the desired PS. In this study, we used bulked segregant analysis with F1 Ningyou 1179 (strong PS) and its F2 population, and through analyzing both parental haplotypes and PS data for 918 hybrid rice varieties, to identify the genetic basis of transgressive late maturation which is dependent on dominance complementation effects of Hd1, Ghd7, DTH8, and PRR37 from both parents rather than from a single parental genotype. We designed a molecular marker-assisted selection system to identify the genotypes of Hd1, Ghd7, DTH8, and PRR37 in parental lines to predict PS in F1 plants prior to crossing. Furthermore, we used CRISPR/Cas9 technique to knock out Hd1 in Ning A (sterile line) and Ning B (maintainer line) and obtained an hd1-NY material with weak PS while retaining the elite agronomic traits of NY. Our findings clarified the genetic basis of transgressive late maturation in hybrid rice and developed effective methods for parental selection and gene editing to facilitate the breeding of hybrid varieties with the desired PS for improving their adaptability.

Editing the nuclear localization signals of E1 and E1Lb enables the production of tropical soybean in temperate growing regions.

Soybean is a typical short-day crop, and most commercial soybean cultivars are restricted to a relatively narrow range of latitudes due to photoperiod sensitivity. Photoperiod sensitivity hinders the utilization of soybean germplasms across geographical regions. When grown in temperate regions, tropical soybean responds to prolonged day length by increasing the vegetative growth phase and delaying flowering and maturity, which often pushes the harvest window past the first frost date. In this study, we used CRISPR/LbCas12a to edit a North American subtropical soybean cultivar named 06KG218440 that belongs to maturity group 5.5. By designing one gRNA to edit the nuclear localization signal (NLS) regions of both E1 and E1Lb, we created a series of new germplasms with shortened flowering time and time to maturity and determined their favourable latitudinal zone for cultivation. The novel partial function alleles successfully achieve yield and early maturity trade-offs and exhibit good agronomic traits and high yields in temperate regions. This work offers a straightforward editing strategy to modify subtropical and tropical soybean cultivars for temperate growing regions, a strategy that could be used to enrich genetic diversity in temperate breeding programmes and facilitate the introduction of important crop traits such as disease tolerance or high yield.

Incorporation of Photoperiod Insensitivity and High-Yield Genes into an Indigenous Rice Variety from Myanmar, Paw San Hmwe

Paw San Hmwe (PSH) is an indigenous rice variety from Myanmar with a good taste, a pleasant fragrance, and excellent elongation ability during cooking. However, its low yield potential and strong photoperiod sensitivity reduce its productivity, and it is vulnerable to climate changes during growth. To improve the photoperiod insensitivity, yield, and plant stature of PSH, the high-yield genes Grain number 1a (Gn1a) and Wealthy Farmer’s Panicle (WFP), together with the photoperiod insensitivity trait, were introgressed into PSH via marker-assisted backcross breeding and phenotype selection. For the photoperiod insensitivity trait, phenotypic selection was performed under long-day conditions during the dry season. After foreground selection of Gn1a and WFP via simple sequence repeat genotyping, genotyping-by-sequencing was conducted to validate the introgression of target genes and determine the recurrent parent genome recovery of the selected lines. The improved lines were insensitive to photoperiod, and the Gn1a and WFP introgression lines showed significantly higher numbers of primary panicle branches and spikelets per panicle than the recurrent parent, with comparative similarity in cooking and eating qualities. This study successfully improved PSH by decreasing its photoperiod sensitivity and introducing high-yield genes via marker-assisted selection. The developed lines can be used for crop rotation and double-season cropping of better-quality rice.