F3 Lines Research Articles

Dependence of the yield in late-generation lines on the spike productivity in original segregating populations of spring bread wheat

Background. An ascertained possibility of culling segregating populations on the basis on their yield or grain weight per spike as a character closely correlated with yield can increase the efficiency of breeding practice with spring bread wheat. Materials and methods. Sixteen F2 –F4 segregating populations of spring bread wheat were assessed for their grain weight per spike, average grain weight per spike among the top 10%, coefficient of variation for grain weight per spike, and yield. The pedigree method was applied to select 2 to 3 F7 lines from each population. The obtained lines were tested for their yield in F8 and F9 . The data of grain weight per main spike in the parents that had been crossed to produce the studied segregating populations were retrospectively taken into account while the results were processed. Results Segregating populations persistently differed in their average grain weight per spike and the coefficient of its variation in different years of research. None of the 36 late-generation lines significantly surpassed the reference cultivar in yield. All the considered indicators of segregating populations had no significant correlations with the yield of late-generation lines. Average values of grain weight per main spike in the parent genotypes and the best parent as well as the differences between the parents in the average grain weight per main spike tended to have a negative correlation with the yield of late-generation lines (r up to –0.58). Conclusion. The culling of segregating populations based solely on the yield or grain weight per spike is associated with a risk of losing high-yielding genotypes. Late-generation lines with high yields occur in combinations where the grain weight per main spike in one parent or on average among the parents is not expressed to its highest level or when both parents differ only slightly from each other in the expression of this character.

Interaction of the cyclin-dependent kinase inhibitor GhKRP6 with RING-Type E3 ligase influences the fiber length in Upland cotton

Upland cotton (Gossypium hirsutum L.) is the major crop producing renewable fiber for textiles. Cotton fiber length is an economically important trait that affects the quality of the yarn. The Upland cotton multi-parent advanced generation intercross (MAGIC) population was developed for genetics research to understand how fiber traits can be improved without reducing fiber yield. A genome-wide association study of the MAGIC population identified a significant fiber length QTL on Chromosome D11 (qFL-D11–1). To understand how the qFL-D11–1 regulates fiber length, we developed F5 lines by crossing the longest and the shortest fiber recombinant inbred lines (RILs) of the MAGIC population to establish lines with parental haplotypes at the qFL-D11–1 but segregating for other loci. The F5 lines and parental RILs were sequenced to detect exchanges from parents' genomic regions in the progeny. One segregating genomic region in the F5 lines coincided with qFL-D12–1, which additively affected fiber length. Correlation analysis of the expression patterns of genes from the two QTLs with the fiber lengths in the MAGIC population showed the highest correlation of the RING-type ubiquitin E3 ligase (GhUbE3) from qFL-D12–1. Kip-related protein-6 (KRP6) is the candidate gene from the qFL-D11–1. A yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated a physical interaction between GhKRP6 (Ghir_D11G020340) and GhUbE3 (Ghir_D12G006080). RNAseq showed that the GhUbE3 expression is reciprocal to the interacting GhKRP6 during fiber development. Virus-induced gene silencing (VIGS) of GhKRP6 increased fiber length. The data indicates that GhUbE3 controls the dose of GhKRP6's inhibitory activity and, therefore, the duration of fiber elongation.

Marker assisted selection and genome recovery for heat tolerance in segregants of rice (Oryza sativa L.)

Abstract In the present global warming scenario, it is urgent to impart heat tolerance into the popular high yielding rice (Oryza sativa L.) varieties to reduce yield loss to a great extent. Uma (a prevalent red-grained rice variety in Kerala) was crossed with Nagina 22 (N22), the popular donor for heat tolerance. From the seven promising heat-tolerant F3 plants previously identified through marker assisted selection and field screening, F4 lines (58 nos.) were raised and characterised morphologically. Heat tolerance was scored under natural heat stress during hot summer months in field conditions. Among the evaluated F4 progenies, 26 promising plants registered >75% spikelet fertility. Double panicles were observed in some of the tillers of fourteen F4 plants. During the selection with reported polymorphic markers between parents, all the 26 F4 plants produced the corresponding amplicon for RM5749 (linked marker for heat tolerance in the parental cross Uma x N22) and also for RM9, RM201, RM208, RM225, RM242, RM495, RM3586, RM6100, RM6836, and RM26212, corresponding to the heat tolerant parent N22. Genomic analysis revealed 64% recovery of the Uma genome in seven F4 plants, with maximum genomic regions of Uma on the chromosomes 3 and 5. These promising F4 plants could be forwarded to generate stable and high yielding heat tolerant rice varieties. The identified markers could be used for linkage analysis and QTL mapping in future. Keywords: Heat stress; Rice; spikelet fertility; SSR; QTL

Fine mapping of two recessive genes TaFLA1 and TaSPL8 controlling flag leaf angle in bread wheat

Flag leaf angle is one of the key target traits in high yield wheat breeding. A smaller flag leaf angle reduces shading and enables plants to grow at a higher density, which increases yield. Here we identified a mutant, je0407, with an 84.34%–89.35% smaller flag leaf angle compared with the wild type. The mutant also had an abnormal lamina joint and no ligule or auricle. Genetic analysis indicated that the ligule was controlled by two recessive genes, which were mapped to chromosomes 2AS and 2DL. The mutant allele on chromosome 2AS was named Tafla1b, and it was fine mapped to a 1 Mb physical interval. The mutant allele on chr. 2DL was identified as Taspl8b, a novel allele of TaSPL8 with a missense mutation in the second exon, which was used to develop a cleaved amplified polymorphic sequence marker. F3 and F4 lines derived from crosses between Jing411 and je0407 were genotyped to investigate interactions between the Tafla1b and Taspl8b alleles. Plants with the Tafla1b/Taspl8a genotype had 58.41%–82.76% smaller flag leaf angles, 6.4%–24.9% shorter spikes, and a greater spikelet density (0.382 more spikelets per cm) compared with the wild type. Plants with the Tafla1a/Taspl8b genotype had 52.62%–82.24% smaller flag leaf angles and no differences in plant height or spikelet density compared with the wild type. Tafla1b/Taspl8b plants produced erect leaves with an abnormal lamina joint. The two alleles had dosage effects on ligule formation and flag leaf angle, but no significant effect on thousand-grain weight. The mutant alleles provide novel resources for improvement of wheat plant architecture.

A locus-dependent mixed inheritance in the segmental allohexaploid sweetpotato (Ipomoea batatas [L.] Lam).

Two interrelated aspects of the sweetpotato genome, its polyploid origin and inheritance type, remain uncertain. We recently proposed a segmental allohexaploid sweetpotato and thus sought to clarify its inheritance type by direct analyses of homoeolog segregations at selected single-copy loci. For such analyses, we developed a digital quantitative PCR genotyping method using one nondiscriminatory and three discriminatory probes for each selected locus to discriminate and quantify three homoeolog-differentiating variation types (homoeolog-types) in genomic DNA samples for genotype fitting and constructed a F2 population for segregation analyses. We confirmed inter-subgenomic distinctions of three identified homoeolog-types at each of five selected loci by their interspecific differentiations among 14 species in Ipomoea section batatas and genotyped the loci in 549 F2 lines, selected F1 progenies, and their founding parents. Segregation and genotype analyses revealed a locus-dependent mixed inheritance (disomic, polysomic, and intermediate types) of the homoeolog-types at 4 loci in the F2 population, displaying estimated disomic-inheritance frequencies of 0, 2.72%, 14.52%, and 36.92%, and probably in the F1 population too. There were also low-frequency non-hexaploid F1 and F2 genotypes that were probably derived from double-reduction recombination or partially unreduced gametes, and F2 genotypes of apparent aneuploids/dysploids with neopolyploid-like frequencies. Additional analyses of homoeolog-type genotypes at the 5 loci in 46 lines from various regions revealed locus-dependent selection biases, favoring genotypes having more of one homoeolog-type, i.e. more of di- or homogenized homoeolog-type composition, and one-direction ploidy trending among apparent aneuploids/dysploids. These inheritance features pointed to an evolving segmental allohexaploid sweetpotato impacted by selection biases.

C17-833 camelina

Camelina ( Camelina sativa) elite germplasm C17-833 was developed at the Agriculture and Agri-Food Canada Saskatoon Research and Development Centre. It was developed through hybridization of camelina cultivar AAC 10CS0048 and F4 line 11CS0231-24-10 and subsequent pedigree selection. C17-833 yields significantly higher (114%) than the check cultivar AAC 10CS0048. It also has significantly higher seed oil content (42.6% vs. 41.9%) and significantly larger seeds (126%). C17-833 has very good resistance to downy mildew disease caused by Hyalonospora camelinae and is adapted to all soil zones of the Canadian Prairies.

IMMUNOMODULATING ACTIVITY OF INDIVIDUAL SUBSTANСES ISOLATED FROM THE AERIAL PART OF RHAPONTICUM UNIFLORUM (L.) DC IN EXPERIMENTAL IMMUNODEFICIENCY

Introduction. The development and introduction of new drugs with immunomodulatory effects is one of the priorities of modern medicine. Numerous studies have proven the immunotropic activity of individual substances isolated from medicinal plants (flavonoids, phenylpropanoids, polysaccharides, ecdysteroids, terpenoids, etc.). In this study, it is of interest to determine the immunomodulatory effect of individual substances isolated from Rhaponticum uniflorum (L.) DC. The purpose of the study. Determine the immunomodulatory properties of 20-hydroxyecdysone, 5-О-caffeoylquinic acid and arabino-3,6-galactan, isolated from the aerial part of Rhaponticum uniflorum (L.) DC, in relation to the cellular and humoral components of the immune response during exper-imental immunosuppression caused by cyclophosphamide. Material and methods. The experiments were performed on 100 male mice of the F1 line (CBAxC57Bl/6) weighing 18-20 g. Immunodeficiency was simulated by in traperitoneal administration of cyclophosphamide at a dose of 250 mg/kg once. The experimental group of animals received individual substances intragastricallyin the following doses: 5-О-caffeoylquinic acid - 10 mg/kg, arabino-3,6-galactan - 10 mg/kg, 20-hydroxyecdysone - 3 mg/kg, once a day for 14 days. The intact group of mice received purified water according to the analogous scheme. The state of humoral chain of the im-mune response was estimated according to the quantity of antibody-forming cells (AFC) determined with the use of Cunningham's plaque assay (1965). The state of the cellular chain of the immune response was estimated according to the delayed hypersensitivity reaction. Study results. It has been established that 20-hydroxyecdysone, 5-О-caffeoylquinic acid and arabino-3,6-galactan, isolated from the aerial part of Rhaponticum uniflorum (L.) DC, have immunomodulatory effect on the cellular and humoral components of the immune response in immunosuppres-sion caused by cyclophosphamide. Conclusions. The obtained results argues the feasibility of further research of individual substances, isolated from the aerial part of Rhaponticum uni-florum (L.) DC, with a view to creating new effective immunomodulators of plant origin.

Identification of genetic loci and candidate genes underlying freezing tolerance in wheat seedlings.

Ten stable loci for freezing tolerance (FT) in wheat were detected by genome-wide association analysis. The putative candidate gene TaRPM1-7BL underlying the major locus QFT.ahau-7B.2 was identified and validated. Frost damage restricts wheat growth, development, and geographical distribution. However, the genetic mechanism of freezing tolerance (FT) remains unclear. Here, we evaluated FT phenotypes of 245 wheat varieties and lines, and genotyped them using a Wheat 90K array. The association analysis showed that ten stable loci were significantly associated with FT (P < 1 × 10-4), and explained 6.45-26.33% of the phenotypic variation. In particular, the major locus QFT.ahau-7B.2 was consistently related to all nine sets of FT phenotypic data. Based on five cleaved amplified polymorphic sequence (CAPS) markers closely linked to QFT.ahau-7B.2, we narrowed down the target region to the 570.67-571.16Mb interval (0.49Mb) on chromosome 7B, in which four candidate genes were annotated. Of these, only TaRPM1-7BL exhibited consistent differential expression after low temperature treatment between freezing-tolerant and freezing-sensitive varieties. The results of cloning and whole-exome capture sequencing indicated that there were two main haplotypes for TaRPM1-7BL, including freezing-tolerant Hap1 and freezing-sensitive Hap2. Based on the representative SNP (+1956, A/G), leading to an amino acid change in the NBS domain, a CAPS marker (CAPS-TaRPM1-7BL) was developed and validated in 431 wheat varieties (including the above 245 materials) and 318 F2 lines derived from the cross of 'Annong 9267' (freezing-tolerant) × 'Yumai 9' (freezing-sensitive). Subsequently, the TaRPM1-7BL gene was silenced in 'Yumai 9' by virus-induced gene silencing (VIGS), and these silenced wheat seedlings exhibited enhanced FT phenotypes, suggesting that TaRPM1-7BL negatively regulates FT. These findings are valuable for understanding the complex genetic basis of FT in wheat.

Validation of molecular markers associated with amylose content of F8 and F9 lines resulting from a crossing of Black Rice and Mentik Wangi

The development of black rice with a fluffier texture at Universitas Jenderal Soedirman, which began in 2004, was carried out by crossing local black rice with the Mentik Wangi variety. At present, six black rice advanced breeding lines are ready for multi-location yield trials. Meanwhile, developing molecular marker-based plant breeding methods can facilitate a more efficient selection process. An important stage in developing molecular markers is marker validation, which aims to test the effectiveness in determining phenotypes in various genotypic and in new populations that differ from others based on the link between the marker and the expected character identified. This research aimed to determine molecular markers that can differentiate the level of amylose content in populations of F8 and F9 lines. The research was carried out on 10 (ten) genotypes consisting of the control variety Logawa, IRPM 112-19- 56, black rice, Mentik Wangi, and six lines. The amplification of the RM190, Wx and SSIIa markers showed polymorphic band. Based on the simple linear regression analysis, in F9, the SSIIa marker had the highest coefficient of determination compared to other markers. Hence, it had the greatest possibility of being a marker for selecting rice based on amylose content.

Adaptive Responses of Biofortified Common Bean Lines to Acidic Soil and High Temperatures in the Colombian Amazon Region

One of the strategies to combat micronutrient malnutrition is by developing biofortified common bean lines (Phaseolus vulgaris L.) capable of tolerating different stress conditions. In this study, the adaptive responses of different biofortified bean lines grown under combined stress of acidic soil and high-temperatures were evaluated in the Colombian Amazon. A total of 247 common bean lines from the Mesoamerican gene pool were used to determine the adaptive response in terms of phenological, physiological, and agronomic behavior under combined stress conditions. The lines tested were obtained from different single crosses, double crosses, and backcrosses between different bean materials, of which 146 were obtained from F4 families with high iron (Fe) content in seed and 99 common bean lines from F5 families. Different bean lines had grain yields (GY) higher than 1400 kg ha−1 from the F5 (lines: 859, 805, 865, and 657) and F4 (lines: 2853 and 2796) families. The superior performance of these lines was related to a higher photosynthate partitioning that has allowed an increase in pod formation (pod partitioning index, PPI) from the canopy biomass (CB) and grain filling (pod harvest index, PHI; harvest index, HI), resulting in higher values of GY. Values of GY were correlated with CB (r = 0.36), PPI (r = 0.6), PHI (r = 0.68), and HI (r = 0.8, p &lt; 0.001). This increase in agronomic performance is due to a greater allocation of energy to the photosynthetic machinery (ΦII) and its dissipation in the form of heat (ΦNPQ), with increases in the leaf temperature difference (LTD). Based on the results obtained, six biofortified lines of common bean (lines F5: 859, 805, 865, and 657; lines F4: 2853 and 2796) showed traits of tolerance to combined stress and can serve as progenitors to increase Fe and Zn concentration in the seeds of lines that tolerate the combined stress from acidic soil and high temperature in the Colombian Amazon region.

Detection and validation of QTLs for green stem disorder of soybean (Glycine max (L.) Merr.).

In mechanically harvested soybean, green stem disorder (GSD) is an undesirable trait that causes green-stained seeds, which are graded lower in Japan. To obtain DNA markers for reduced GSD, we conducted a quantitative trait locus (QTL) analysis for 2 years using F4 and F5 lines from a cross between 'Suzuotome' (less GSD) and 'Fukuyutaka' (more GSD). We validated the effect of a detected QTL for GSD by first identifying F4 or F5 plants in which one or more markers in the QTL region were heterozygous. The F5 or F6 progeny of each plant was used to form a pair consisting of two groups in which the QTL region was homozygous for either the 'Suzuotome' or 'Fukuyutaka' allele in a similar genetic background, and the two groups within each pair were compared for GSD. Over 3 years of testing, the 'Suzuotome' allele of a QTL on chromosome 6 was found to reduce the level of GSD. This novel QTL was mapped to the region around DNA marker W06_0130, and was not closely linked to QTLs for important agronomic traits including yield components. Using this marker, the low level of GSD from 'Suzuotome' could be conferred to 'Fukuyutaka' or other high-GSD cultivars.

Genetic Map Construction Using F2 and RIL/DH Mapping Population.

Genetic mapping is the determination of the position and relative genetic distance between genes or molecular markers in the chromosomes of a particular species. The construction of genetic maps uses data from the genotyping of the mapping population. Among the different mapping populations used, two are relatively common: the F2 and recombinant inbred lines (RILs) obtained as a result of the controlled crossing of genetically diverse parental forms (e.g., inbred lines). Also, the dihaploid (DH) population is often used in plants, but obtaining DHs in different crops, including rye, is very difficult or even impossible. Any molecular marker system can be used for genotyping. Polymorphic markers are used for linkage analysis, differentiating parental forms with segregation in the mapping population, consistent with the appropriate single-gene model. A genetic map is a great source of information on a species and can be an exquisite tool for analyzing important quantitative traits (QT).This chapter presents the procedure of genetic map construction with two different algorithms using the JoinMap5.0 program. First, the Materials section briefly informs about the mapping program, showing how to obtain a mapping population and prepare data for mapping. Finally, the Methods section describes the protocol for the mapping procedure itself.

Interaction between genetic regions responsible for the starch properties in non-glutinous rice varieties in Hokkaido, Japan.

Starch properties are the major determinants of grain quality and food characteristics in rice (Oryza sativa L.). Understanding the interactions between genetic regions responsible for starch properties will lead to the development of rice cultivars with desirable characteristics. This study investigated the genetic effect and interaction between qAC9.3, a low-amylose quantitative trait locus (QTL), and the genetic region around Starch branching enzyme IIb (SbeIIb). Both these factors are responsible for the starch properties of the Hokkaido breeding population. The amylose content, pasting temperature, and amylopectin chain-length distribution were compared using F5 lines derived from the cross between the lower amylose content and lower pasting temperature strain 'Hokkai332 (qAC9.3, SbeIIb)' and the higher amylose content and higher pasting temperature variety 'Kitagenki (-, SbeIIbsr )'. The qAC9.3 genotype exhibited low amylose content and reduced the hardness of boiled rice but increased the ratio of amylopectin long chains and did not alter the pasting temperature. In contrast, the SbeIIb genotype was associated with pasting temperature but did not affect the amylose content and hardness of boiled rice. It was suggested that appropriately selecting genotypes of these genetic regions and QTL would allow the fine-tuning of starch properties of cooked rice suitable for future demand.

Performances of F3 and F4 Bulk Populations in Cotton (Gossypium hirsutum L.)

The experiment was laid out in 2020 to compare the performance of thirty-seven F3 and F4 multi-parental bulk populations of cotton, including comparative cultivars, and to assess the heritability of traits studied. The differences within generations were significant for seed cotton yield, ginning out-turn, fiber quality, and nep fragments. The mean fiber strength of the F4 generation showed significant performance compared with F3. The broad sense heritability was high for ginning out-turn, fiber length, and fiber strength. The normal distribution for F3 and F4 generations due to non-significant skewness and kurtosis values indicated that there were no epistatic effects on the heritability of traits studied. Eight F4 lines were selected for transfer to F5 generation according to optimization in terms of desired traits.

Responses of interspecific hybrid eggplant f4 inbred lines to drought and heat stress

Eggplant is grown in and near the tropic and sub-tropic zones where climate change effects can be seen dramatically in agricultural production. As a vegetable, it is considered has tolerance to some abiotic stresses compared to others. However, significant reductions in yield and marketable fruit quality were observed under stress conditions that exceeded the tolerance level. Eggplant has wild relatives which are known as tolerant to stresses. As a part of the comprehensive project this research includes drought-tolerant line development from the F4 population obtained by interspecific crossing between Solanum incanum L., a wild relative of eggplant naturally distributed in the Sub-Saharan zone, and a pure line with superior characteristics developed in BATEM. Qualified 50 inbred lines were selected as drought tolerant among F3 progenies in previous studies. In this experiment, 12 plants from each 50 genotypes at F4 level were exposed to drought stress, which was created by 25% watering of full irrigation. On the 25th day of treatment, tolerant plants were distinguished by using 0-5 scale. From each genotype, 4 plants were selected as drought tolerant, and they were transferred to greenhouse to identify their heat tolerance. Among the drought-tolerant group 42 F4 lines were found as heat tolerant.

BSA-seq identified candidate genes and diagnostic KASP markers for anemone type flower in chrysanthemum

Chrysanthemum is one of the most leading commercial flower crops well-known for its flower shape diversity. Anemone type chrysanthemums receive increasing market attention that are distinguished by their pigmented and elongated disk florets. However, there are few reports on quantitative trait loci (QTL) mapping and the identification genes for anemone in chrysanthemum. In this study, bulked segregant analysis coupled with whole-genome sequencing (BSA-seq) approach was employed to detect candidate genomic regions controlling anemone type flower. Two mixed DNA pools composed of 28 anemone type and 20 non-anemone type F1 lines derived from a cross between ‘Nannong Xuefeng’ and ‘Monalisa’ together with two parents were used for high-throughput sequencing. A total of 42 consistent QTLs covering 30.00 Mb were simultaneously identified by |△(SNP/InDel-index)| and Euclidean distance (ED) algorithms based on 15,783,313 SNPs (single-nucleotide polymorphisms) and 1,546,200 small InDels (insertions and deletions). Twenty-two key candidate genes were screened out by a combination of gene functional annotation and transcriptome analysis, in which evm.model.scaffold_915.436 (CBF5), evm.model.scaffold_24.208 (U2AF65A), and a uncharacterized gene evm.model.scaffold_260.201 were highlighted by qRT-PCR. Furtherly, four associations were successfully converted to KASP (kompetitive allele specific PCR) markers, among them, the KASP markers developed for SNP locus Chr6__33961007 and Chr6__179207697 were proven to efficiently discriminate anemone and non-anemone type chrysanthemums being a couple of diagnostic markers in two populations. The results presented herein provide insights for further research on elucidating the formation mechanism of anemone type flower, and the anemone-specific KASP marker will be highly useful for applying MAS to accelerate breeding improvement of chrysanthemum.

Evaluation of the distinct and uniformity of upland rice superior varieties candidates

Rice production needs to be increased by using new superior varieties of upland rice. Currently, 5 promising lines of upland rice have been produced through plant breeding programs. Before being registered as a variety, plant variety canadidates must have distinct and uniform criteria. This research was conducted to determine distinctiveness, uniformity and recommendations for 5 promising lines as candidates for upland rice of new superior varieties. This research was conducted from August 2022 to March 2023 at the Experimental and Research Station, Universitas Bangka Belitung. The research material consists of 5 F8 lines and 5 comparison varieties. Data analysis used the Analysis of Variance (ANOVA) followed by the Duncan Multiple Range Test (DMRT) and uniformity test. The results of ANOVA test showed were significant differences in the characters of plant height, flag leaf length, panicle length, filled grain weight per clump, and 1000 grain weight. The promising lines show distinct characteristics of seed color, plant height, number of productive tillers, and panicle length. Narrow variability values indicate a high level of uniformity with the expected lines of uniformity ranging from 88-100%. Lines 23A-56-22-20-05 (brown rice) and 23A-56-20-07-20 (white rice) with high production are recommended as candidates for new superior varieties of upland rice.

Evaluation of plant characteristics of early harvesting hybrid chili lines

Chili pepper is a popular horticultural commodity grown across the tropics, including Indonesia. The availability of chili varieties, particularly hybrids, may extend options for growers as well as consumers, depending on their personal preferences and needs. In 2022, research was conducted in the Lembang highlands agroecosystem, West Java, Indonesia, with the aim to evaluate plant characteristics including plant morphology and production of F1 chili lines. Five genotypes were employed in a complete randomized block design with four replications, including two F1 lines (1 x 5 and 5 x3) and three commercial F1 hybrid varieties (Carla Agrihorti, Hot Beauty, and Inata Agrihorti). The 1 x 5 line had a short plant posture, characterized by the short stem length, internodes, and plant height. This line also had the earliest flowering (44.25 dap) as well as harvesting (96 dap). This 1 x 5 line‘s advantage was complimented by a high yield of 16.7 tons Ha-1. The F1 1 x 5 line is expected to be efficient in the use of water, fertilizer, and pesticides due to its short plants and early harvest but high yield, allowing it to contribute to sustainable agriculture and have a beneficial impact on the environment.

Echinochloa crus-galli seedlings surviving florpyrauxifen-benzyl applications have a greater potential to produce resistant seeds

Abstract Florpyrauxifen-benzyl (FPB) is an important postemergence rice herbicide. This study tested the potential for seed production in an FPB-resistant barnyardgrass population. A barnyardgrass population (NL) collected from a rice field in eastern China was highly resistant to FPB with a GR50 dose (the FPB dose causing a 50% reduction in fresh weight of aboveground parts) of 50.2 g ai ha−1. No significant differences in the percentages of surviving seedlings after treatment with different doses of the herbicide were found between F1 lines collected from F0 plants surviving a 36 g ai ha−1 FPB treatment and those collected from nontreated control F0 plants. Additionally, no significant differences were found in the rate of surviving seedlings after treatment with varying doses of FPB among the F2 lines collected from F1 plants that survived varying doses of FPB. At a constant temperature of 30 C, seeds from different F1 and F2 lines showed germination percentages of 85% to 92.0% and 68.3% to 89.0%, respectively. In the absence of competition, plants from the NL population surviving 0–144 g ai ha−1 FPB showed no significant differences in plant height, dry weight of aboveground parts, effective accumulated temperature (EAT) from sowing to seed maturation, seed production per plant, or 1,000-seed weight. In the susceptible population (HJ), plants surviving 18 g ai ha−1 FPB showed no significant differences compared to the nontreated control plants of the same population for the above variables. This is the first report of FPB-resistant barnyardgrass in China. Barnyardgrass seedlings that survived FPB application showed a higher potential for accumulating in the soil seedbank and negatively affecting rice.

Methods for evaluating effects of transgenes for quantitative traits

AbstractTransgenes that improve quantitative traits have traditionally been evaluated in one or a few genetic backgrounds across multiple environments. However, testing across multiple genetic backgrounds can be equally important to accurately quantify the value of a transgene for breeding objectives. Creating near‐isogenic lines across a wide germplasm space is costly and time consuming, which renders it impractical during early stages of testing. In this experiment, we evaluate three approaches to sample the genetic space while concurrently testing across environments. We created both transgenic and non‐transgenic doubled haploid maize (Zea mays L.) lines, F2:3 lines, and bulk F3 families to determine if all methods resulted in similar estimation of transgene value and to identify the number of yield trial plots from each method necessary to obtain a stable estimate of the transgene value. With one exception, the three methods consistently estimated a similar effect of the transgene. We suggest that bulked F3 lines topcrossed to a tester inbred is the most effective method to estimate the value of a transgene across both genetic space and environments.