Study of Androgenic Plant Families of Alloplasmic Introgression Lines (H. vulgare) –T. aestivum and the Use of Sister DH Lines in Breeding (original) (raw)
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Androgenesis in flowering plants is a unique biological process. It provides an understanding of the biological basis of single-cell microspore embryogenesis to the production of a dihaploid plant. This system provides an unparalleled opportunity to shorten the breeding cycle and fix agronomic traits in the homozygous state, such as recessive genes for disease resistance. The most desirable dihaploid variation in all the major crops including rice, wheat, barley, maize, rape, cotton, sunflower, coffee, etc. has already been developed and utilized in modern crop breeding. Many known and a few unknown factors are involved in such development. A few noteworthy factors are donor plants, genotypic variation, media composition, and handling of cultures, which may have a greater influence on the response of androgenesis. A further opportunity has arisen to use a pollen-specific gene, promoter and transgenic dihaploid (homozygous), gene expression, proteomics, translational regulation and post-translational modification of genes to widen the scope of crop improvement. The homozygous (isogenic) lines will provide unique genetic material for mapping populations for use in functional genomics and molecular breeding.
On the genetic improvement of androgenetic haploid formation in Hordeum vulgare L
TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik, 1982
Anthers of 55 different spring barley (Hordeum vulgare) hybrids and four varieties were cultured in vitro. Microspores of each hybrid gave rise to calluses and subsequently plantlets, from all hybrids, except one. As criteria of microspore responsiveness, callus formation and plant regeneration frequencies were studied in detail. Large differences with regard to these criteria were found, which were traced back to the genotype of the anther donor plant. Callus formation varied between 3.3 and 73.2 per 1,000 anthers plated, whereas green plant regeneration ranged from 0 to 12.7 per 1,000 anthers cultured.Comparisons of microspore regeneration frequencies of hybrids and their parents indicated that culture responsiveness is a heritable, complex character involving at least two different and separately inherited mechanisms: 1) the ability of microspores within anthers to divide and give rise to calluses and subsequently 2) the ability of calluses for morphogenesis, to yield green or al...
The origin of clones among androgenic regenerants of hexaploid triticale
Euphytica, 2014
Doubled haploids (DH) have become a standard tool in breeding and genetic studies of many crops and in most cases androgenesis is the only available route of their production. It has been recently observed that some populations of DH lines obtained via androgenesis contain high proportions of clones. This seriously reduces the efficiency of breeding and may jeopardize genetic studies. This study was designed to determine at which stage of androgenesis these clones are created, using samples set aside during routine production of DH lines in breeding of hexaploid triticale. The fate of each androgenic structure was carefully followed through the entire regeneration process, and all obtained plants were genotyped using DNA markers. Overall, 189 plants were regenerated forming 33 families, each originating from a single original androgenic structure (callus, polyembryos). In ca. 80 % of cases all members of a family were genetically identical. However, in about 20 % of cases the families of regenerants were genetically heterogeneous, showing that not all androgenic structures originate from single microspores. The evidence shown here demonstrates that retention of single plants from each original structure guarantees the production of only unique genotypes but it reduces the total output of plants. If maximum output is desired, multiple regenerants from single callus can be retained but must be genotyped using at least 10 polymorphic markers to identify clones.
Frontiers in Plant Science, 2015
The use of doubled haploids in onion breeding is limited due to the low gynogenesis efficiency of this species. Gynogenesis capacity from Spanish germplasm, including the sweet cultivar Fuentes de Ebro, the highly pungent landrace BGHZ1354 and the two Valenciana type commercial varieties Recas and Rita, was evaluated and optimized in this study. The OH-1 population, characterized by a high gynogenesis induction, was used as control. Growing conditions of the donor plants were tested with a one-step protocol and field plants produced a slightly higher percentage of embryogenesis induction than growth chamber plants. A one-step protocol was compared with a two-step protocol for embryogenesis induction. Spanish germplasm produced a 2-3 times higher percentage of embryogenesis with the two-step protocol, Recas showing the highest percentage (2.09%) and Fuentes de Ebro the lowest (0.53%). These percentages were significantly lower than those from the OH-1 population, with an average of 15% independently of the protocol used. The effect of different containers on plant regeneration was tested using both protocols. The highest percentage of acclimated plants was obtained with the two-step protocol in combination with Eco2box (70%), whereas the lowest percentage was observed with glass tubes in the two protocols (20-23%). Different amiprofosmethyl (APM) treatments were applied to embryos for chromosome doubling. A similar number of doubled haploid plants were recovered with 25 or 50 µM APM in liquid medium. However, the application of 25 µM in solid medium for 24 h produced the highest number of doubled haploid plants. Somatic regeneration from flower buds of haploid and mixoploid plants proved to be a successful approach for chromosome doubling, since diploid plants were obtained from the four regenerated lines. In this study, doubled haploid plants were produced from the four Spanish cultivars, however further improvements are needed to increase their gynogenesis efficiency.
Creation of pepper doubled haploids and morphological characterization of androgenic plants
Euphytica, 2021
The Balkan pepper breeding program aims to use in vitro embryogenesis (anther culture) to develop doubled haploid pepper lines with valuable traits. We analyzed the effectiveness of microspore embryogenesis on 17 pepper genotypes comprised of varieties, breeding lines, and F 1 hybrids of different varietal types (conical, bell shape, and kapia) and characterized the agronomic traits of newly generated doubled haploid lines. The highest androgenic potential was observed in the variety Stryama and breeding line 560/06 with 9.55 and 13.00% reacted anthers, respectively. Of the 186 regenerated plants, 147 were successfully adapted with a survival index of 79.03%. Flow cytometry analysis showed that the haploid:diploid ratio of regenerants was 1.5:1. All diploid plants were confirmed to be androgenic in origin. There were significant differences in terms of quantitative fruit characteristics of length, width, weight, pericarp weight, pericarp thickness, and productivity per plant among the diploid lines. Also, androgenic lines 21, 23, and 74 derived from Stryama and line 55 obtained from Zlaten medal 7 were distinguished with higher values of some fruit traits compared to initial genotypes. Additionally, several androgenesis lines (Stryama lines 21, 23, and 74, and Zlaten medal 7 line 55) scored higher for some fruit traits compared to the initial genotype. These results show that anther culture is a promising tool for the creation of Balkan pepper breeding lines with improved traits. Keywords Androgenesis Á Doubled haploid breeding Á Haploid:diploid regenerants Á Balkan pepper Á Kapia Abbreviations DH Doubled haploid PPFD Photosynthetic proton flux density CV Coefficient of variation
Production of double haploids in ornamental crops
2020
Double haploids are the plants, generated spontaneously or induced by chromosome duplication of a haploid plant. They are homozygous at all loci which make them a unique line from the parent in respect of its genome constituent. There is a significant utilization of double haploids in breeding program like production of homozygous lines for cross pollinated crops and mutation breeding. Due to haploidization of chromosomes and again doubling them can produce some novel traits, which cannot be expressed under existing diploid condition. This technique has a significant impact on the improvement program of floricultural crops like chrysanthemum, carnation, petunia, rose, iris, lily, phlox etc. Haploids occur spontaneously at a lower frequency but they can be induced by several methods, such as modified pollination methods in vivo (Wide hybridization, Chromosome elimination, Pollination with irradiated pollen, etc.) and by In vitro culture of immature gametophytes. They are made chromos...
The effect of auxin and genotype on the production of Avena sativa L. doubled haploid lines
Production of doubled haploid (DH) cereals is becoming increasingly important in crop breeding programs , but the methods currently applied still remain inefficient. In this study, we present the procedure for obtaining haploid and DH oat plants by pollination with maize. Thirty-three oat genotypes were used in the experiments. Oat plants (14,543 florets) were pollinated with maize pollen 2 days after emasculation and treated with auxin analogues: 2,4-dichlorophenoxyacetic acid (2,4-D) or 3,6-dichloro-2-methoxybenzoic acid (dicamba), at a concentration of 100 mg dm-3. These auxins had no significant influence on the number of haploid embryos developed , but they significantly affected their germination ability, and thus haploid and DH plant production. After application of 2,4-D, 5.06 % of haploid embryos developed per emasculated florets, 1.37 % of haploid plants and 0.54 % of DH lines, whereas after dicamba treatment, 4.3 % of haploid embryos, 0.64 % of haploid plants and 0.25 % of DH lines. Haploid embryos were obtained from all genotypes tested, however, their frequency differed between individual genotypes. The highest number of embryos per emasculated florets (9.0 %) was obtained from the DC09040 genotype after dicamba treatment, and from STH123 9 Skorpion (8.9 %) after 2,4-D treatment. The genotype did not significantly affect the development of haploid plants, nevertheless the highest number of DH lines was obtained from the Arab 9 Typhon genotype. There were 52 DH lines acquired from 28 genotypes, which produced a total of 5227 seeds. The number of seeds varied between the DH lines from 2 to 595. Seeds of all the DH lines produced fertile next generation. DH lines are currently included in breeding programs.
Floriculture, Ornamental and Plant Biotechnology: Advances and Topical Issues Vol. II, 2006
Tomatoes and cereals are becoming increasingly popular ornamentals in Japan, the former as fruiting pot plants, the latter as dry bouquet supplements. To obtain interspecific hybrids of tomato and its wild species, immature globular-stage embryos were taken out and cultured on suitable medium, on which somatic embryos were formed with globular, heart and torpedo stages. When the initially-obtained embryos were recultured on the same medium, secondary somatic embryos were formed and they grew to complete plants. Hereby a clonal propagation system of hybrid embryos was established. Cotyledons of tomato seedlings cultured in a controlled environment chamber were used as materials for protoplast isolation, and plant regeneration was obtained via somatic embryogenesis on TM medium (Shahin 1985). Subsequently, cotyledon protoplasts of tomato treated with iodoacetamide and suspension-culture-derived protoplasts of wild species were fused using polyethylene glycol, and somatic embryos were derived from greenish calli that formed from the fusion mixtures, developed progressively through the globular, heart, and torpedo stages, and finally formed complete plants. In parallel, to establish a simple and efficient culture system of vegetative tissues from monocots for gene transformation, guinea grass and bahia grass were used as starting materials. The leaflet tissues were taken from terminal tillers arising at the end of stolons, cut into 5-mm long pieces, washed, sterilized and then placed on MS medium (Murashige and Skoog 1962). Embryogenic calli were formed and they were observed by scanning electron microscopy, indicating somatic embryo structure with a scutellum and a coleoptile. Multiple shoot and plant regeneration were obtained from somatic embryos. A simple ovary culture system of both was also established via somatic embryogenesis.
TURKISH JOURNAL OF BIOLOGY, 2016
Doubled haploid (DH) plant production plays an important role in pepper (Capsicum annuum L.) breeding for development of new varieties. However, information is lacking for DH plant production in pepper genotypes carrying ornamental value. The major goal of this study was to produce DH ornamental pepper lines having the mentioned value. Androgenic responses of 48 genotypes at the F 2 or F 3 generation were compared in each of three androgenesis protocols to determine the most effective method. Of the three protocols tested, anthers were placed on two different semisolid culture media and on a double-layer medium also called shedmicrospore culture medium. The results revealed that the shed-microspore culture protocol was superior to both semisolid anther culture protocols. The average numbers of total and normal-looking embryos per bud of the most responsive genotype were 102.90 and 34.11, respectively. We report here, a total of 122 regenerated ornamental pepper plants with ornamental value; 63 DH, 52 haploid, and 7 mixoploid plants were produced in the present study. The spontaneous diploidization rate was 51.6% based on flow cytometry analyses. The results showed that the shed-microspore culture protocol could be used effectively for the development of DH lines in ornamental pepper breeding programs.