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Twenty-one quantitative trait loci were discovered across six environments, including three (NS), seven (LS) and eleven (VLS) conditions. The linkage groups 1A, 1B, 2A, 2B, 2D, 3B, 4A, 6A, 6B and 7D spanned quantitative trait loci (QTLs). For canopy temperature (CT), a stable QTL (Qct_rpcau_4A) in the environment E6 has shown a phenotypic variance (PVE) up to 17.85%. The QTL, Qspad_rpcau_2D, was found to be stable for SPAD value, explaining the PVE of 15.05%. Whereas, three stable QTLs viz. Qgy_rpcau_3B, Qgy_rpcau_4A and Qgy_rpcau_6A were associated with the chromosomes 3B, 4A and 6B explaining a PVE of 20.85%, 17.43% and 17.37% respectively for the trait GY. The interaction of genotype and environment has been shown to be useful in determining the best lines for heat-stressed environments. In addition, G X E analysis was performed on the population. In the ranking of genotypes for both mean yield and mean vs. stability, GGE biplot across the six environments, DH 146, 195, 60, 202, 65, 155, 124, 5, 201, 169, 15 and 170 were ranked closest to ideal and winning genotype; these were highly adapted and most stable lines. The goal of the current investigation was to find the best suitable double haploid lines which can withstand heat stress and to find those QTLs which are influential to heat stress for the studied traits. [ABSTRACT FROM AUTHOR]

Breeders are turning to rapid breeding methods in order to respond to the increasing population for the breeding of the wheat plant, which has a very important place in human nutrition. One of the biotechnological methods to shorten wheat breeding, which takes 15-20 years with classical breeding methods, is double haploid. The aim of this study is to obtain double haploid lines by taking wheat genotypes that have reached the F2 generation after hybridization into anther culture and thus shorten the breeding period. When looking at the response to anther culture of the 15 different F2 combinations used in the study, F2-7 and F2-10 genotypes stood out as the most successful genotypes. It was observed that 4 different groups were formed among 15 genotypes according to the success rate. It was concluded that the success of anther culture varies depending on the genotypes used, the nutrient media and the suitability of laboratory conditions. [ABSTRACT FROM AUTHOR]

Vegetables are the richest source of vitamins and minerals and play a major role in nutritional security. The primary objective of vegetable breeding is enhancing production and productivity. Breeders use various conventional and non-conventional breeding approaches for genetic advance. Recent advances in biotechnology helps to enhance the efficiency and shorten the time required to achieve the fixed goals in a breeding program, as well as to address the economic and ecological goals. Among these, haploid (H) and doubled haploid (DH) production through gametic embryogenesis has long been recognized as a valuable tool to help crop improvement. Haploid plants are the sporophytes with a gametophytic chromosome number and doubled haploids (DH) are haploids that have undergone chromosome duplication. Haploids and double haploids occur spontaneously in nature. Haploids can also be induced artificially by various techniques such as wide hybridization, pollination with irradiated pollens androgenesis, gynogenesis and finally further chromosome doubling results in double haploids. Production of double haploids in vegetables will shorten the breeding cycle and also DH technology is useful in reverse breeding, CMS line production, gene stacking and various other genetic studies. [ABSTRACT FROM AUTHOR]

Rapeseed is a significant global source of plant oil. Silique size, particularly silique length (SL), impacts rapeseed yield. SL is a typical quantitative trait controlled by multiple genes. In our previous study, we constructed a DH population of 178 families known as the 158A-SGDH population. In this study, through SL QTL mapping, we identified twenty-six QTL for SL across five replicates in two environments. A QTL meta-analysis revealed eight consensus QTL, including two major QTL: cqSL.A02-1 (11.32–16.44% of PVE for SL), and cqSL.C06-1 (10.90–11.95% of PVE for SL). Based on biparental resequencing data and microcollinearity analysis of target regions in Brassica napus and Arabidopsis, we identified 11 candidate genes at cqSL.A02-1 and 6 candidate genes at cqSL.C06-1, which are potentially associated with silique development. Furthermore, transcriptome analysis of silique valves from both parents on the 14th, 21st, and 28th days after pollination (DAP) combined with gene function annotation revealed three significantly differentially expressed genes at cqSL.A02-1, BnaA02G0058500ZS, BnaA02G0060100ZS, and BnaA02G0060900ZS. Only the gene BnaC06G0283800ZS showed significant differences in parental transcription at cqSL.C06-1. Two tightly linked insertion-deletion markers for the cqSL.A02-1 and cqSL.C06-1 loci were developed. Using these two QTL, we generated four combinations: A02SGDH284C06158A, A02SGDH284C06SGDH284, A02158AC06158A, and A02158AC06SGDH284. Subsequent analysis identified an ideal QTL combination, A02158AC06SGDH284, which exhibited the longest SL of this type, reaching 6.06 ± 0.10 cm, significantly surpassing the other three combinations. The results will provide the basis for the cloning of SL-related genes of rapeseed, along with the development of functional markers of target genes and the breeding of rapeseed varieties. [ABSTRACT FROM AUTHOR]

The production of double haploids ("DH") by microspore-derived embryos is one of the best breeding methods to generate new varieties with better traits and stable genetic background. In the previous study, radish 'DH' lines were generated with a different range of glucosinolate (GSL) contents, ranging from low to high levels of GSL. In this study, we performed metabolic and transcriptional profiling to elucidate the regulatory system behind the GSL biosynthesis process using the 'DH' radish lines. Four individual 'DH' lines were selected, of which two lines named 'HH' had high GSL content, while the other two lines, 'LL', had low GSL content. HPLC analysis in the vegetative (leaf and root) and reproductive tissue (seed) was detected seven GSL compounds from radish. Among seven GSLs, glucoraphasatin (GRH) occupied the largest proportion of total GSLs in both leaf and root tissues, while glucoraphenin (GRE) was taking a place as the major GSL in radish seeds. Six major genes (RsBCAT4, RsIPMDH1, RsCYP79F1, RsCYP83A1, RsUGT74B1, and RsGRS1) representing the major biosynthesis of aliphatic GSLs were selected for qRT-PCR analysis. Heat map analysis based on Pearson correlation coefficient showed that RsBCAT4, RsIPMDH1, RsCYP79F1, and RsCYP83A1 were positively correlated with the amount of GRH in leaf tissue. Meanwhile, RsGRS1 showed a strong correlation with the amount of GRH and total aliphatic GSLs in both leaf and root tissues. By using the 'DH' radish lines, this study revealed that regardless of tissues of radish, accumulation of total GSL is strongly affected by the RsGRS1 and also positively supported by the other biosynthetic genes like RsBCAT4, RsIPMDH1, RsCYP79F1, and RsCYP83A1. [ABSTRACT FROM AUTHOR]

Sweetpotato (Ipomoea batatas L.) is a strategic crop with both economic and energy value. However, improving sweetpotato varieties through traditional breeding approaches can be a time-consuming and labor-intensive process due to the complex genetic nature of sweetpotato as a hexaploid species (2n = 6x = 90). Double haploid (DH) breeding, based on in vivo haploid induction, provides a new approach for rapid breeding of crops. The success of haploid induction can be achieved by manipulating specific genes. Two of the most critical genes, DMP (DUF679 membrane proteins) and MTL (MATRILINEAL), have been shown to induce haploid production in several species. Here, we identified and characterized DMP and MTL genes in sweetpotato using gene family analysis. In this study, we identified 5 IbDMPs and 25 IbpPLAs. IbDMP5 and IbPLAIIs (IbPLAIIκ, IbPLAIIλ, and IbPLAIIμ) were identified as potential haploid induction (HI) genes in sweetpotato. These results provide valuable information for the identification and potential function of HI genes in sweetpotato and provide ideas for the breeding of DH lines. [ABSTRACT FROM AUTHOR]

To keep pace with the skyrocketing demand of vegetable oil and reduced dependency on import, there is a need to focus on indigenous oilseed crops, such as niger (Guizotia abyssinica L.F. Cass). Niger is a minor oilseed crop that consists of 32 to 40% quality oil and 18 to 24% protein in the seeds. Despite its considerable importance, self-incompatibility and high outcrossing pose difficulty in breeding through conventional methods. Double haploid (DH) technology is one of the alternatives to overcome the problem and develop inbred lines in a shorter time. In context to this, a highly efficient protocol for DH production through anther culture in Indian niger varieties JNS 9 and JNS 28 was developed. The investigation was conducted to identify the suitable microspore stage for anther culture, cold pre-treatment, hormonal combinations for callus induction (T1–T4), shooting (S1–S26), rooting (R1–R3), hardening, ploidy index, and the effect of different colchicine treatments on the efficiency of the developed protocol. Anthers in disc florets of light green to greenish yellow color have uninucleate microspores (7 d of bud initiation). For callus initiation, Murashige and Skoog (MS) medium containing 2.0 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.3 mg L−1 kinetin (KIN) showed 100% efficiency. For shoot initiation, 37 to 40% greening was observed on MS medium with 0.5 mg L−1 6-benzylaminopurine (BAP) and 0.5 mg L−1 activated charcoal and, subsequently, 19% shoot emergence on MS medium containing 0.5 mg L−1 BAP and 0.5 mg L−1 KIN. Low efficiency of shoot regeneration was addressed by adding 0.2% colchicine for 30 h at the callusing stage which resulted in 90 to 95% increased efficiency in shooting. For rooting, MS medium containing 2.0 mg L−1 indole-3-butyric acid (IBA) was efficient with a frequency of 85 to 90% followed by hardening in 1:1:1 ratio of vermiculite:sand:soil in pots. Ploidy indexing was done using cell size analysis followed by chromosome count using a microscope which confirmed the ploidy level of regenerants as compared to diploid control. Thus, the procedure developed in the study demonstrates the successful development of DH which in turn facilitates the acceleration of the breeding program through the development of homozygous inbreds and new cultivars. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Nanjing Agricultural University / Nanjuing Nongye Daxue Xuebao is the property of Journal of Nanjing Agricultural University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Zinc (Zn) deficiency is a common limiting factor in agricultural soils, which leads to significant reduction in both the yield and nutritional quality of agricultural produce. Exploring the quantitative trait loci (QTL) for shoot and grain Zn accumulation would help to develop new barley cultivars with greater Zn accumulation efficiency. In this study, two glasshouse experiments were conducted by growing plants under adequate and low Zn supply. From the preliminary screening of ten barley cultivars, Sahara (0.05 mg/pot) and Yerong (0.06 mg/pot) showed the lowest change in shoot Zn accumulation, while Franklin (0.16 mg/pot) had the highest change due to changes in Zn supply for plant growth. Therefore, the double haploid (DH) population derived from Yerong × Franklin was selected to identify QTL for shoot mineral accumulation and biomass production. A major QTL hotspot was detected on chromosome 2H between 31.91 and 73.12 cM encoding genes for regulating shoot mineral accumulations of Zn, Fe, Ca, K and P, and the biomass. Further investigation demonstrated 16 potential candidate genes for mineral accumulation, in addition to a single candidate gene for shoot biomass in the identified QTL region. This study provides a useful resource for enhancing nutritional quality and yield potential in future barley breeding programs. [ABSTRACT FROM AUTHOR]

Bounteous modern and innovative biotechnological tools have resulted in progressive development in the barley breeding program. Doubled haploids developed (homozygous lines) in a single generation is significant. Since the first discovery of haploid plants in 1920 and, in particular, after discovering in vitro androgenesis in 1964 by Guha and Maheshwari, the doubled haploidy techniques have been progressively developed and constantly improved. It has shortened the cultivar development time and has been extensively used in: genetic studies, gene mapping, marker/trait association, and QTL studies. In barley, the haploid occurrence developed gradually from being a sporadic and random process (spontaneous) to haploid development by in vivo method of modified pollination or by in vitro culture of immature male or female gametophytes. Although significant improvement in DH induction protocols has been made, challenges still exist for improvement in areas such as: low efficiency, albinism, genotypic specificity etc. Here, the paper focuses on: haploidization via different in vitro, in vivo techniques, the recent advances technologies like centromere‐mediated haploidization, hap induction gene, and Doubled haploid CRISPR. The au-courant work of different researchers in barley using these technologies is reviewed. Studies on different factors affecting haploid induction and work on genome doubling of barley haploids to produce DH lines via spontaneous and induced technologies has also been highlighted. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Agronómica is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ovule number (ON) produced during flower development determines the maximum number of seeds per silique and thereby affects crop productivity; however, the genetic basis of ON remains poorly understood in oilseed rape (Brassica napus). In this study, we genetically dissected the ON variations in a double haploid (DH) population and in natural population (NP) by linkage mapping and genome-wide association analysis. Phenotypic analysis showed that ON displayed normal distribution in both populations with the broad-sense heritability of 0.861 (DH population) and 0.930 (natural population). Linkage mapping identified 5 QTLs related to ON, including qON-A03, qON-A07, qON-A07-2, qON-A10, and qON-C06. Genome-wide association studies (GWAS) revealed 214, 48, and 40 significant single-nucleotide polymorphisms (SNPs) by individually using the single-locus model GLM and the multiple-locus model MrMLM and FASTMrMLM. The phenotypic variation explained (PVE) by these QTLs and SNPs ranged from 2.00–17.40% to 5.03–7.33%, respectively. Integration of the results from both strategies identified four consensus genomic regions associated with ON from the chromosomes A03, A07, and A10. Our results preliminarily resolved the genetic basis of ON and provides useful molecular markers for plant yield improvement in B. napus. [ABSTRACT FROM AUTHOR]

The development of Fusarium head blight (FHB)-resistant winter wheat cultivars using the gene Fhb1 has been conducted in northern China. Sumai 3, a Chinese FHB-resistant spring wheat cultivar, carries three FHB resistance genes: Fhb1, Fhb2 and Fhb5. To better use these genes for increasing FHB resistance in northern China, it is necessary to elucidate the pyramiding effects of Fhb1, Fhb2 and Fhb5 in winter wheat backgrounds. Eight gene combinations involving Fhb1, Fhb2 and Fhb5 were identified in a double haploid (DH) population, and the effects on FHB resistance were evaluated in six tests. At the single gene level, Fhb1 was more efficient than the other two genes in single-floret inoculation tests, whereas Fhb5 showed better resistance than Fhb1 and Fhb2 under a natural infection test. Pyramiding Fhb1, Fhb2 and Fhb5 showed better FHB resistance than the other gene combinations. Forty-nine DH lines showing consistently better resistance than the moderately susceptible control Huaimai 20 in multiple tests were evaluated for main agronomic traits, and no difference in grain yield was found between the mean values of DH lines and the recipient parents Lunxuan 136 and Lunxuan 6, which are higher than those of recipient parent Zhoumai 16 and the donor parent Sumai 3 (p < 0.05). Based on the phenotypic and genomic composition analyses, five promising DH lines fully combined the FHB resistance of donor Sumai 3 and the elite agronomic traits from the recipient parents. This study elucidates the pyramiding effects of three FHB resistance genes and that the promising DH lines with resistance to FHB can be directly applied in wheat production or as parents in winter wheat breeding programs. [ABSTRACT FROM AUTHOR]

The DH lines derived from PBW343 × IC252478 were sown for three distinct sowing dates for the years 2017–2018 and 2018–2019. The area chosen for this study was chosen because it is a hot spot for wheat production, and heat stress is a major limitation for wheat growers. In this study, three replicates of the alpha lattice design were employed. Stability measures and genotype–environment interaction were shown to be valuable methods in determining the best lines for heat-stressed environments. Out of 165 DH lines, DH 71, DH 150, DH 34, DH13 DH 64, DH 138, DH 98, DH 84, DH 62, DH 104, DH 74, DH 3, DH 104, DH 107, and DH 156 were ranked closest to ideal and winning genotype in the ranking of genotypes for mean yield, mean versus stability, GGE biplot, and stability performance across the six environments; these were highly adapted, most stable, heat-tolerant, and high-yielding lines. Moreover, the population was also subjected to quantitative trait loci (QTL) mapping for which composite interval mapping (CIM) was performed and it unravelled a total of 36 QTLs where 6 QTLS were detected in non-stressed and 30 QTLs in heat-stressed condition. The detected QTLs spanned on 1A, 1D, 2B, 2D, 3B, 4D, 5B, and 6D chromosomes. The overall goal of the current investigation was to find the best suitable double haploid lines which can withstand heat stress and to find those QTLs which are influential to heat stress for yield-related traits. [ABSTRACT FROM AUTHOR]

Anther culture technique is one of the commonly used method in order to obtain haploid plants in eggplant. It is known that androgenic response in eggplant is variable and one of the most important factors determining success is the genotype effect. Low or insufficient embryogenic response limits the use of doubled haploid technology in breeding programs. Therefore, determining the embryogenic responses of genotypes is a step for the use of this technology in breeding studies. In this study, 61 eggplant genotypes at various breeding stages (F1, F2, and F3) in the gene pool of United Genetics Vegetable Seeds Company (Mustafakemalpaşa, Bursa, Turkey) were evaluated in terms of androgenic responses. Significant differences were determined among eggplant genotypes in terms about embryo induction and conversion rates of embryos to full plantlets. In the study, responsiveness to anther culture based on genotype ranged from 0.0%-21.58%. The conversion rate of induced embryos to plants varied between 0.0% and 100%. [ABSTRACT FROM AUTHOR]

Double haploids (DHs) production and utilization is an important aspect of wheat breeding programs in worldwide, because, it provides many advantages over the conventional breeding program. Therefore, in vitro and in vivo responses of anther derived two bread wheat cultivars and their F1 crosses were investigated. Results showed significant genetic variation among the tested bread wheat genotypes. The pre-cold treated anther derived embryonic calli and shoot induction (%) were obtained from all genotypes that ranged 44 - 76% and 32 - 58% respectively. The highest shoot induction from embryonic calli was achieved from F1 cross of Zubkov x Atay-85, whereas, lowest induction was obtained from Atay-85 cultivar. The F1 cross (Zubkov x Atay-85) showed a better response in anther culture in term of shoots per plant and root induction than their respective parental genotypes. The present results indicated positive and significant heterotic effects of F1 crosses for calli and shoot induction that also showed less albino plant regeneration after colchicine treatments. Total number of 114 anthers driven DHs lines from two genotypes and their F1 crosses were regenerated, confirmed by flow-cytometry and evaluated under field condition. Some DHs lines were found to be significantly superior for agronomical traits including seed yield than the parental genotypes as well as local bread wheat (control) cultivars. [ABSTRACT FROM AUTHOR]

Summary: Reactive oxygen species (ROS) play important roles during anther and pollen development. DNA damage may cause chromosome fragmentation that is considered to underlie chromosome elimination for haploid induction by matrilineal pollen, a key step in MATRILINEAL‐based double haploid breeding technology. But when and how DNA damage occurs is unknown.We performed comparative studies of wheat pollens from the wild‐type and the CRISPR/Cas9 edited matrilineal mutant (mMTL).Chemical assays detected a second wave of ROS in mMTL pollen at the three‐nuclei‐stage and subsequently, along with reduced antioxidant enzyme activities. RNA‐seq analysis revealed disturbed expression of genes for fatty acid biosynthesis and ROS homoeostasis. Gas chromatography‐mass spectrometry measurement identified abnormal fatty acid metabolism that may contribute to defective mMTL pollen walls as observed using electron microscopy, consistent with the function of MTL as a phospholipase. Moreover, DNA damage was identified using TdT‐mediated dUTP nick‐end labelling and quantified using comet assays. Velocity patterns showed that ROS increments preceded that of DNA damage over the course of pollen maturation.Our work hypothesises that mMTL‐triggered later‐stage‐specific ROS causes DNA damage that may contribute to chromosome fragmentation and hence chromosome elimination during haploid induction. These findings may provide more ways to accelerate double haploid‐based plant breeding. [ABSTRACT FROM AUTHOR]

The experiments were conducted during kharif (June to September) 2018 and 2019 to screen 7 aromatic rice double haploid (DH) lines developed against Bacterial Leaf Bligh (BLB) and blast disease. Three genes Xa21, xa13, xa5 for BLB resistance and two genes Pi1, Pi2 for blast resistance was introgressed into a local aromatic rice variety Dubraj from Chhattisgarh State of India. Dubraj is extremely popular aromatic short medium grain variety in Chhattisgarh and Madhya Pradesh region and hence used in this study. RPBIO-226 and PR122 rice variety is used as donor for BLB and blast resistance respectively. 7 DH lines (L-1 to L-7) were developed from the crosses (Dubraj X RPBIO-226 X PR122) in the year 2017. Phenotypic evaluation for BLB diseases resistance has shown that L-1, L-6 and L-7 (score 1) has a similar resistance as the control check RPBIO-226(score-1) and 3 lines with moderate resistance (L-3 score 2) (L-4 score 3) (L-5 score 3). For blast disease, three lines (L-4, L-6 and L-7) were identified as resistance with the disease score of 1, whereas three were grouped under the section moderately resistant (L-1, L-3 and L-5) with a disease score of 3. Sensory test (1.7% KOH) was conducted for the estimation of presence / absence of aroma. Moderately strong aroma was present in four lines (L-1, L-3, L-6 and L-7). On the basis of yield and presence of aroma in grain, L-3 has been selected with moderately resistant to BLB and blast for further advancement and subsequently evaluated under State Initial Evaluation Trial (SIET) during kharif 2020. Within 3 years of development of DH line, L-3 is under varietal developmental trail, which itself indicate the efficacy of anther culture in fixing homozygosity and speedy development of desired variety within short period of time. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronómica is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Alfalfa (Medicago Sativa), a perennial cross-pollinated plant, is one of the most important forage crops in the world with commercial value and ecological significance. However, due to the complexity of its genome, varietal improvement is difficult. Therefore, generating genetically homozygous materials have greater significance for breeding. In the current study, we aimed to identify the best tissue culture conditions to obtain haploid plants and double haploid plants. Methods: In this study, the haploid plants of alfalfa were obtained by combining tissue culture regeneration system with Flow cytometry. Different concentrations of colchicine were applied to the haploid plants using solid and liquid cultivation methods to determine the optimum conditions to obtain double haploid plants of Medicago Sativa L. cv. 'XinJiangDaYe'. Result: Among the two colchicine cultivation methods tested, the doubling rate of regenerated plants obtained by liquid cultivation method was higher and the leaves developed under this system have the best doubling effect among the three explants tested. Optimal doubling conditions for alfalfa haploid (Medicago Sativa L. cv. 'XinJiangDaYe') were identified. The double haploid plant material generated from the current study could serve as a genetic resource for developing the hybrid combinations and for analyzing genetic linkage in alfalfa improvement programs. [ABSTRACT FROM AUTHOR]

Breeding using the double haploid approach has been used in accelerating the rice breeding process. However, the main obstacle in the application of this technique in rice is the low level of callus formation and their regeneration into haploid plants. Based on these issues, this research is aimed at developing the best method for obtaining double haploid plants through anther culture using three kinds of aromatic rice of Indonesian local varieties. Anthers of Pendok, Genjah Arum, and Merah Wangi varieties were cultured in callus induction media which were either supplemented with different types of carbon sources, or auxins and ethylene inhibitors. However, the application of different sugar types did not significantly affect callus formation of Pendok and Genjah Arum. However, auxin treatment showed NAA to be more efficient for the callus induction of Pendok, while 2,4-D had no effect on callus induction in all tested varieties. The addition of ethylene inhibitor successfully induced callus formation of Merah Wangi varieties, while the rates of Pendok and Genjah Arum were not significantly affected. Callus of three plant lines were then regenerated into plantlet in regeneration media. Of the three callus varieties used, only Pendok could regenerate into plantlets and grow into adult haploid plants. [ABSTRACT FROM AUTHOR]

Identifying iron- and zinc-related quantitative trait loci (QTL) with consistent effects across environments and genetic backgrounds is necessary to develop rice varieties with high grain iron content (GIC) and grain zinc content (GZC). In this work, a doubled haploid population was developed through a cross between the Korean japonica cultivars Goami 2 and Hwaseonchal and phenotyped during the 2018 wet season (POP2018) and 2019 wet season (POP2019). The milled rice grains of POP2018 and POP2019 were used to identify GIC- and GZC-related QTL that was consistent between years. Digenic interactions and genes that affected GIC and GZC were also identified. Paired sample t test revealed that the GIC of POP2018 was not significantly different from that of POP2019 (t = 0.24, p =0.81), whereas the GZC of POP2018 was significantly different from that of POP2019 (t = − 4.35, p =0.00). Three moderate-effect (phenotypic variance [PVE] < 10.00%) GIC- and GZC-related QTL that were consistent between POP2018 and POP2019 were identified through inclusive composite interval mapping: qFe9, qFe11, and qZn7. All three QTL originated from the inferior parent Hwaseonchal. Epistasis analysis revealed that the GIC and GZC of POP2018 and POP2019 were affected by 79 significant digenic interactions with moderate and minor effects. By contrast, GZC was unaffected by digenic interactions. An interaction between loci on chromosomes 1 and 5 provided the highest contribution to the PVE (13.72%) for GIC. Candidate gene analysis revealed that 12 genes related to iron and zinc homeostasis or that require iron or zinc as ligands colocated with qFe9, qFe11, and qZn7. The QTL and epistatic regions identified here may be useful for developing rice varieties with high GIC and GZC in their milled grains. [ABSTRACT FROM AUTHOR]

Copyright of Yuzuncu Yil Universitesi Journal of Agricultural Sciences (YYU J Agr Sci) is the property of Yuzuncu Yil University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Brinjal is a popular vegetable crop in India and widely used in culinary, pickle and industrial purposes. The double haploid technique is used in vegetable crop improvement; thus, reducing lengthy conventional breeding timelines to develop new improved varieties. A study was conducted to develop a robust double haploid (DH) protocol in brinjal. Six genotypes and six media combinations were tested. Two media types showed DH production in brinjal ranging from 0.34-9.27 %. Consequently, MSB-6 is recommended media for brinjal DH in light of the obtained results. Similarly, five out of six genotypes showed DH responsiveness. The genotype-wise responsiveness to anther culture ranged from 2.29 - 7.40 %. DH technique complements the plant breeder's effort to bring new varieties in the shortest time. Therefore, the relevance of improvement in tissue culture assisted double haploidy and continuous improvement of available protocols remains relevant even after six decades of its original discovery. [ABSTRACT FROM AUTHOR]

Rice double haploid (DH) plants are produced mainly through anther culture. In order to improve the anther culture protocol, microspores of two japonica rice genotypes (NRVC980385 and H28) were subjected to three growth regulator combinations and four colchicine treatments on induction medium. In addition, a post anther culture procedure using colchicine or oryzalin was tested to induce double haploid plantlets from haploid plantlets. A cold pre-treatment of microspores for 9 days at 10 °C increased callus induction 50-fold in the NRCV980385 genotype. For both genotypes, 2 mg L−1 2,4-D and 1 mg L−1 kinetin on colchicine-free induction medium gave the best culture responses. The culturability of both genotypes changed on colchicine-supplemented induction media. A high genotype dependency was recorded for callus induction, callus regenerating green plantlets and regeneration of green double haploid plantlets. Colchicine at 300 mg L−1 for 48 h enhanced callus induction 100-fold in H28. Colchicine-supplemented media clearly improved green double haploid plantlet regeneration. We showed that the post-anther culture treatment of haploid plantlets at 500 mg L−1 of colchicine permitted fertile double haploid plantlets to be generated. Finally, an enhanced medium-throughput flow cytometry protocol for rice was tested to analyse all the plantlets from anther and post anther culture. [ABSTRACT FROM AUTHOR]

A study was conducted to augment a viable protocol for the development of double haploid system in cauliflower, using in-house genotypes, by anther culture. A total of 13,680 anthers were cultured on different media combinations across nine genotypes. Genotypeto-(segregating) genotype variations in anther culture to plant regeneration were observed, chiefly, segregating genotype-9, had highest frequency of regeneration (26.43%) whereas, segregating genotype-2, had the lowest frequency (0.2%). Two segregating genotypes remained unresponsive. Anther cultured on modified media showed highest embryogenic callus induction potential as compared to other media compositions. Regeneration media, RM1 and RM2, showed good differentiation and regeneration potential. In total, 711 haploid / double haploid plants were developed across seven genotypes, with an average regeneration efficiency of 7.6%. This simple protocol reported here, can be used for DH line development in cauliflower, through anther culture, resulting in embryogenic callus induction and plant regeneration. Further, protocol developed and discussed in the paper, will help to exploit DH technology in cauliflower for rapid inbred line development, and to speed-up cauliflower breeding for faster cultivar and better hybrid development. [ABSTRACT FROM AUTHOR]

Haploids and doubled haploids are critical components of plant breeding. This review is focused on studies on haploids and double haploids inducted in cucurbits through in vitro pollination with irradiated pollen, unfertilized ovule/ovary culture, and anther/microspore culture during the last 30 years, as well as comprehensive analysis of the main factors of each process and comparison between chromosome doubling and ploidy identification methods, with special focus on the application of double haploids in plant breeding and genetics. This review identifies existing problems affecting the efficiency of androgenesis, gynogenesis, and parthenogenesis in cucurbit species. Donor plant genotypes and surrounding environments, developmental stages of explants, culture media, stress factors, and chromosome doubling and ploidy identification are compared at length and discussed as methodologies and protocols for androgenesis, gynogenesis, and parthenogenesis in haploid and double haploid production technologies. [ABSTRACT FROM AUTHOR]

Using seeds of inbred progenies of Cucurbita pepo L. DH12-11409 double haploids as experimental materials, the effects of different hormone combinations, explant types and seedling ages on adventitious bud regeneration and rooting of C. pepo L. were investigated. According to the results, inoculating cotyledonary nodes of yellow-green cotyledons from 5-d-old C. pepo L. double haploids to MS + 30 g/L Sue + 8 g/L Agar + 2.0 mg/L 6-BA +0.1 mg/L NAA led to the best results with the induction frequency of 90.0% and differentiation coefficient of 8.5. MS medium with addition of 0.05 or 0.1 mg/L NAA led to the highest rooting rate. Regenerated seedlings with 5-6 true leaves exhibited the highest survival rate of 90.0%, which was the optimal period for domestication and transplanting of regenerated seedlings. This study laid a solid foundation for high-efficiency utilization of heterosis of C. pepo L. [ABSTRACT FROM AUTHOR]

Chrysanthemum is one of important ornamental species in the world. Its highly heterozygous state complicates molecular analysis, so it is of interest to derive haploid forms. A total of 2579 non-fertilized chrysanthemum ovules pollinated by Argyranthemum frutescens were cultured in vitro to isolate haploid progeny. One single regenerant emerged from each of three of the 105 calli produced. Chromosome counts and microsatellite fingerprinting showed that only one of the regenerants was a true haploid. Nine doubled haploid derivatives were subsequently generated by colchicine treatment of 80 in vitro cultured haploid nodal segments. Morphological screening showed that the haploid plant was shorter than the doubled haploids, and developed smaller leaves, flowers, and stomata. An in vitro pollen germination test showed that few of the haploid's pollen were able to germinate and those which did so were abnormal. Both the haploid and the doubled haploids produced yellow flowers, whereas those of the maternal parental cultivar were mauve. Methylation-sensitive amplification polymorphism (MSAP) profiling was further used to detect alterations in cytosine methylation caused by the haploidization and/or the chromosome doubling processes. While 52.2% of the resulting amplified fragments were cytosine methylated in the maternal parent's genome, the corresponding proportions for the haploid's and doubled haploids' genomes were, respectively, 47.0 and 51.7%, demonstrating a reduction in global cytosine methylation caused by haploidization and a partial recovery following chromosome doubling. [ABSTRACT FROM AUTHOR]

Microspore embryogenesis involves reprogramming of the pollen immature cell towards embryogenesis. We have identified and characterized a collection of 14 genes induced along different morphological phases of microspore-derived embryo development in wheat ( Triticum aestivum L.) anther culture. SERKs and FLAs genes previously associated with somatic embryogenesis and reproductive tissues, respectively, were also included in this analysis. Genes involved in signalling mechanisms such as TaTPD1- like and TAA1b, and two glutathione S-transferase ( GSTF2 and GSTA2) were induced when microspores had acquired a 'star-like' morphology or had undergone the first divisions. Genes associated with control of plant development and stress response ( TaNF- YA, TaAGL14, TaFLA26, CHI3, XIP- R; Tad1 and WALI6) were activated before exine rupture. When the multicellular structures have been released from the exine, TaEXPB4, TaAGP31- like and an unknown embryo-specific gene TaME1 were induced. Comparison of gene expression, between two wheat cultivars with different response to anther culture, showed that the profile of genes activated before exine rupture was shifted to earlier stages in the low responding cultivar. This collection of genes constitutes a value resource for study mechanism of intra-embryo communication, early pattern formation, cell wall modification and embryo differentiation. [ABSTRACT FROM AUTHOR]

Copyright of Folia Horticulturae is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With 2 figures and 4 tables Abstract Net type net blotch (NTNB) is an important barley disease in Australia and elsewhere, inducing significant yield reduction. 'WPG8412' was resistant against Australian NTNB isolates 97NB1 and NB73, whereas 'Pompadour' and 'Stirling' showed differential responses to these isolates. Using these lines, three F1-derived double haploid populations that comprised 194 double haploid lines (DHLs) of 'WPG8412' ×'Stirling', 116 DHLs of 'WPG8412' × 'Pompadour' and 206 DHLs of 'Pompadour' × 'Stirling' were tested against these two isolates. Bimodal segregation indicated a major gene for resistance was operative: in 'WPG8412' × 'Stirling' against 97NB1; in 'WPG8412'×'Pompadour' against NB73; and in 'Pompadour' × 'Stirling' against either of the isolate. This major gene was mapped using simple sequence repeat (SSR) markers on chromosome 6H in the centromeric region in all three populations. This work demonstrated that 6H region controlling NTNB is a complex locus, where at least three alleles or closely linked genes are possible in these parents against these isolates. This is a first report of 6H complexity for NTNB resistance against Australian isolates. [ABSTRACT FROM AUTHOR]

Background: Brassica rapa is an economically important crop and a model plant for studies concerning polyploidization and the evolution of extreme morphology. The multinational B. rapa Genome Sequencing Project (BrGSP) was launched in 2003. In 2008, next generation sequencing technology was used to sequence the B. rapa genome. Several maps concerning B. rapa pseudochromosome assembly have been published but their coverage of the genome is incomplete, anchoring approximately 73.6% of the scaffolds on to chromosomes. Therefore, a new genetic map to aid pseudochromosome assembly is required. Results: This study concerns the construction of a reference genetic linkage map for Brassica rapa, forming the backbone for anchoring sequence scaffolds of the B. rapa genome resulting from recent sequencing efforts. One hundred and nineteen doubled haploid (DH) lines derived from microspore cultures of an F1 cross between a Chinese cabbage (B. rapa ssp. pekinensis) DH line (Z16) and a rapid cycling inbred line (L144) were used to construct the linkage map. PCR-based insertion/deletion (InDel) markers were developed by re-sequencing the two parental lines. The map comprises a total of 507 markers including 415 InDels and 92 SSRs. Alignment and orientation using SSR markers in common with existing B. rapa linkage maps allowed ten linkage groups to be identified, designated A01-A10. The total length of the linkage map was 1234.2 cM, with an average distance of 2.43 cM between adjacent marker loci. The lengths of linkage groups ranged from 71.5 cM to 188.5 cM for A08 and A09, respectively. Using the developed linkage map, 152 scaffolds were anchored on to the chromosomes, encompassing more than 82.9% of the B. rapa genome. Taken together with the previously available linkage maps, 183 scaffolds were anchored on to the chromosomes and the total coverage of the genome was 88.9%. Conclusions: The development of this linkage map is vital for the integration of genome sequences and genetic information, and provides a useful resource for the international Brassica research community. [ABSTRACT FROM AUTHOR]

With 2 figures and 5 tables Net type net blotch (NTNB) is an important barley disease in Australia and elsewhere, with significant yield reduction. This trait is important in selection along with other traits of quality and agronomic value. Two-hundred doubled-haploid lines were generated through anther culture from a cross between ‘Pompadour’ and ‘Stirling’. Quantitative trait loci (QTL) were identified against five isolates of Pyrenophora teres f. teres, which represent virulences across Australia. QTL were mapped on chromosomes 3H and 6H using simple sequence repeat (SSR) markers. The resistance locus on 6H was detected with all isolates while the 3H locus was detected with two isolates. The 6H QTL from ‘Pompadour’ contributed resistance to isolates 97NB1, 95NB100 and NB81, whereas 6H QTL from ‘Stirling’ contributed resistance to isolates NB50 and NB52B. The 3H QTL from ‘Pompadour’ contributed resistance to NB50 and NB52B. Significant epistatic interactions were detected between QTL on 3H and 6H. These resistance QTL are a useful resource and identifying closely linked SSR markers with allelic combinations will facilitate in marker-assisted selection to develop NTNB resistant breeding lines. [ABSTRACT FROM AUTHOR]

Although barley is extensively grown in the Peruvian highlands as a food crop, agricultural and quality performance have historically been poor. A double-haploid technique was used to obtain barley varieties better suited to this environment. Three crosses were constructed: Ya/LM94, B16/LM94 and B12/LM94. From all crosses, F1 anthers were cultured in vitro to produce double-haploid lines. At DH6, promising materials were evaluated in the Peruvian highlands, along with their parents and two commercial controls (PPch, UNA80). Expert agronomic criteria for the ideal barley cultivar for this region were defined and Euclidean distance was used for simultaneous selection of the recorded agricultural traits. Ya/LM94-PC27 exhibited the shortest Euclidean distance to the expert criteria (0.41), higher yield than controls, and low plant height. Periods from first rain to flowering and maturity suited growth during the rainy season. Ya/LM94-PC27 was resistant to stripe rust, and its grain protein content suited the malting-brewing industry. Hectoliter and 1,000-grain masses met or surpassed industry requirements. [ABSTRACT FROM AUTHOR]

Blackleg, caused by Leptosphaeria maculans, is a major disease of oilseed rape ( Brassica napus), worldwide, including Australia and France. The aims of these studies were first, to determine if higher levels of resistance to L. maculans could be generated in double haploid (DH) lines derived from spring-type B. napus cv. Grouse, which has a good level of field resistance to blackleg; and second, to determine whether the resistance to blackleg disease of individual DH lines responds differentially to different L. maculans field populations within and between the two countries. DH lines were extracted from cv. Grouse and tested in field experiments carried out in both France and Australia against natural L. maculans populations. Extracting and screening DH lines were an effective means to select individual lines with greatly improved expression of resistance to blackleg crown canker disease in comparison with the original parental population. However, relative disease resistance rankings for DH lines were not always consistent between sites. The higher level of resistance in France was shown to be because of a high expression level of quantitative resistance in the French growing conditions. Big differences were observed for some DH lines between the 2004 and the 2005 field sites in Australia where the L. maculans populations differed by their virulence on single dominant gene-based resistant lines derived from Brassica rapa ssp. sylvestris. This differential behaviour could not be clearly explained by the specific resistance genes until now identified in these DH lines. This investigation highlights the potential to derive DH lines with superior levels of resistance to L. maculans compared with parental populations. However, in locations with particularly high pathogen diversity, such as in southern Australia, multiyear and multisite evaluations should be performed to screen for the most efficient material in different situations. [ABSTRACT FROM AUTHOR]

Copyright of Genome is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The response, in terms of capsaicinoid content, of chile ( Capsicum annuum L.) genotypes to different environments was studied. Double haploidlines, an F1 hybrid, and an open-pollinated cultivar estimated the genotype, environment, and genotype-by-environment interaction effect on the total capsaicinoids and on individual capsaicinoids. Significant differences were observed among the genotypes and among genotype-by-environment interactions over the environments. Among the genotypes in an environment, the within-genotype variances were also significantly different. The double haploid line, HDA 207, had low within-genotype variance for individual and total capsaicinoids, with the exception of the isomer of dihydrocapsaicin. Also for HDA 270, the genotype-by-environment interaction was negligible for individual and total capsaicinoids, Indicating stability across environments. [ABSTRACT FROM AUTHOR]

Sixty one double haploid (DH) lines were evaluated for yield components and yield and compared with the three corresponding hybrids from which they were derived through anther culture. Analysis of a 6×6 diallel experiment led to the selection of these hybrids based on their high heterosis and revealed the nature of gene action of the characters under evaluation. The DH lines along with the hybrids and parents were planted following a simple lattice design with two replications. The results show that in DH lines the values of the characters expressing predominantly additive genetic effects could reach the heterotic level of the hybrids. For characters including yield showing predominantly dominance effects, values in the DH lines were significantly lower than those of the corresponding hybrids. The promising DH lines, however, possess a higher yield potential than the better parents. [ABSTRACT FROM AUTHOR]

Background: Farmed Atlantic salmon are one of the most economically significant global aquaculture products. Early sexual maturation of farmed males represents a significant challenge to this industry and has been linked with the vgll3 genotype. However, tools to aid research of this topic, such as all-male and clonal fish, are still lacking. The present 6-year study examined if all-male production is possible in Atlantic salmon, a species with heteromorphic sex chromosomes (males being XY, females XX), and if all-male fish can be applied to further explore the vgll3 contribution on the likelihood of early maturation. Results: Estrogen treatment of mixed sex yolk sac larvae gave rise to one sexually mature hermaphrodite with a male genotype (XY) that was used to produce both self-fertilized offspring and androgenetic double haploid (dh) offspring following egg activation with UV treated sperm and pressure shock to block the first mitotic division. There were YY supermales among both offspring types, which were crossed with dh females. Between 1 and 8% of the putative all-male offspring from the eight crosses with self-fertilized supermales were found to have ovaries, and 95% of these phenotypic females were also genetically female. None of the offspring from the one dh supermale cross had ovaries. When assessing the general contribution of the vgll3 locus on the likelihood of early post-smolt sexual maturation (jacking) in the all-male populations we found individuals that were homozygous for the early maturing genotype (97%) were more likely to enter puberty than individuals that were homozygous for the late maturing genotype (26%). However, the likelihood of jacking within individuals with an early/late heterozygous genotype was higher when the early allele came from the dam (94%) compared to the sire (45%). Conclusions: The present results show that supermale Atlantic salmon are viable and fertile and can be used as a research tool to study important aspects of sexual maturation, such as to further explore the sex dependent parental genetic contribution to age at puberty in Atlantic salmon. In addition, we report the production of viable double haploid supermale fish. [ABSTRACT FROM AUTHOR]

Production of homozygous lines derived from transgenic plants is one of the important steps for phenotyping and genotyping transgenic progeny. The selection of homozygous plants is a tedious process that can be significantly shortened by androgenesis, cultivation of anthers, or isolated microspores. Doubled haploid (DH) production achieves complete homozygosity in one generation. We obtained transgenic homozygous DH lines from six different transgenic events by using anther culture. Anthers were isolated from T0 transgenic primary regenerants and cultivated in vitro. The ploidy level was determined in green regenerants. At least half of the 2n green plants were transgenic, and their progeny were shown to carry the transgene. The process of dihaploidization did not affect the expression of the transgene. Embryo cultures were used to reduce the time to seed of the next generation. The application of these methods enables rapid evaluation of transgenic lines for gene function studies and trait evaluation. [ABSTRACT FROM AUTHOR]