scholarly journals Evaluation of Gynogenic Responsiveness and Pollen Viability of Selfed Doubled Haploid Onion Lines and Chromosome Doubling via Somatic Regeneration

2010 ◽  
Vol 135 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Marijana Jakše ◽  
Pablo Hirschegger ◽  
Borut Bohanec ◽  
Michael J. Havey

Although haploid induction has been used in onions (Allium cepa L.) for over 20 years, several obstacles limit its use in plant breeding programs. To address these limitations, we evaluated the responsiveness of doubled haploid (DH) lines and their selfed progenies, an alternative protocol for chromosome doubling using somatic regeneration of haploid lines, and pollen viability of DH lines. Twenty-one DH lines were self pollinated and tested for haploid induction in the second generation. Among the DH lines, 18 lines showed an average of 20% decrease in gynogenic responsiveness compared with the original lines, while three lines registered an average increase of 5.7%. Using a two-step induction/regeneration procedure, 8,589 somatic regenerants were obtained from 16,170 flower buds from haploid plants, and shoot culture was established. A more laborious procedure using extraction of ovaries in the regeneration stage was found equal to flower bud culture. Chromosome doubling via somatic regeneration was found to be 83% and 100% efficient when the source material was haploid or mixoploid, respectively. Based on the results achieved in this and previous studies, an alternative protocol for chromosome doubling of gynogenic haploids is proposed.

2019 ◽  
Vol 132 (12) ◽  
pp. 3227-3243 ◽  
Author(s):  
Vijay Chaikam ◽  
Willem Molenaar ◽  
Albrecht E. Melchinger ◽  
Prasanna M. Boddupalli

Key Message Increased efficiencies achieved in different steps of DH line production offer greater benefits to maize breeding programs. Abstract Doubled haploid (DH) technology has become an integral part of many commercial maize breeding programs as DH lines offer several economic, logistic and genetic benefits over conventional inbred lines. Further, new advances in DH technology continue to improve the efficiency of DH line development and fuel its increased adoption in breeding programs worldwide. The established method for maize DH production covered in this review involves in vivo induction of maternal haploids by a male haploid inducer genotype, identification of haploids from diploids at the seed or seedling stage, chromosome doubling of haploid (D0) seedlings and finally, selfing of fertile D0 plants. Development of haploid inducers with high haploid induction rates and adaptation to different target environments have facilitated increased adoption of DH technology in the tropics. New marker systems for haploid identification, such as the red root marker and high oil marker, are being increasingly integrated into new haploid inducers and have the potential to make DH technology accessible in germplasm such as some Flint, landrace, or tropical material, where the standard R1-nj marker is inhibited. Automation holds great promise to further reduce the cost and time in haploid identification. Increasing success rates in chromosome doubling protocols and/or reducing environmental and human toxicity of chromosome doubling protocols, including research on genetic improvement in spontaneous chromosome doubling, have the potential to greatly reduce the production costs per DH line.


2021 ◽  
pp. 1-10
Author(s):  
Sourbh Kumar ◽  
Uttam Chandel ◽  
Satish Kumar Guleria

Abstract An investigation to optimize the protocol for application of colchicine for enhancing the doubled haploid production in maize was done. 106 maize genotypes were used as maternal parents, whereas, pollen source involved tropically adopted haploid inducer (TAIL P1 and TAIL hybrid). After the elimination of chromosomes of inducer lines, haploid seeds were obtained from the crosses. Haploid seedlings were treated with three different doses, such as 0.04, 0.06 and 0.08 per cent of colchicines for different durations (8, 12 and 15 hours). The response of various colchicine concentrations applied for different time durations revealed significant differences at P ≤ 0.05 for various parameters viz., per cent plants survivability, stalk colour, the fertility of tassel, silk present/absent, pollen viability, seed set and per cent doubled haploid formation. In maize, colchicine doses of 0.04 per cent for 12 hours and 0.06 per cent for 8 hours, respectively were established as optimum for enhanced doubled haploid production. But among these two, 0.04 per cent for 12 hours was observed to be best dose for doubled haploid production in maize.


2018 ◽  
Vol 30 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Katarina Rudolf Pilih ◽  
Urška Karolina Potokar ◽  
Borut Bohanec

Abstract Protocols leading to the development of doubled haploid (DH) lines by microspore culture are widely used in white cabbage (Brassica oleracea var. capitata L.), but efficiency varies according to the cultivar and induction procedure. Forty different genotypes consisting of F1 cultivars and their crosses with responsive doubled haploid lines were tested to evaluate the androgenic response. In total, 20,032 embryos were produced. On average, the haploid induction response of F1 cultivars was 7.0 embryos/Petri dish, but the average of these hybrids crossed to responsive DH lines was 26.6 embryos/Petri dish. In seven reciprocal crosses, a difference was observed in just one, meaning that the maternal effect probably has a minor influence on haploid embryogenesis in cabbage. Addition of 0.02% activated charcoal (AC) to the induction media increased embryo formation in several low-responsive genotypes, but its effect on embryo formation of high-responsive genotypes was predominantly negative, although larger embryos were formed on media containing AC than without AC. Further development into plantlets was tested by two procedures. Formed embryos were either transferred directly to regeneration medium or treated with abscisic acid and desiccated for 4 weeks. Regrowth and further development reached on average 15.5 and 57.6%, for the first and second procedures, respectively. Plantlets developed by direct transfer often exhibited abnormal development or hyperhydricity, unlike the desiccated embryos. Spontaneous diploidisation of embryos reached 42.5% in total and was not affected by AC added to the induction media.


HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 990B-990 ◽  
Author(s):  
Ryan L. Walker ◽  
Sunggil Kim ◽  
Javier F. Betran ◽  
Kilsun Yoo ◽  
Leonard M. Pike

Onions suffer from severe inbreeding depression, which has inhibited the development of homozygous inbred lines in breeding programs. The creation of doubled haploid (DH) lines in onion provides a unique opportunity to evaluate the utility of such lines as parents in a breeding program. For this purpose, two diallele cross experiments were conducted. The first consisted of a six-parent diallele cross using six DH lines developed at Texas A&M University. The second, a four-parent diallele cross performed with two DH lines and two inbred lines from the breeding program. Bulbs from the various crosses were evaluated for diameter, height, centers/bulb, ring thickness, number of rings/bulb, bulb weight, soluble solids content, and pungency. For some traits, general combining ability (GCA) effects explained most of the variation. However, for other traits, specific combining ability (SCA) effects predominated. For all traits, GCA and SCA were always larger than the reciprocal effects (divided into maternal and nonmaternal components). The GCA and SCA effects show an inverse correlation between the number of centers/bulb and ring thickness.


Author(s):  
A Berbec ◽  
D Laskowska

AbstractA total of 51 doubled haploid (DH) derivatives of the flue-cured true-breeding tobacco variety Wislica were obtained via anther culture and colchicine-induced chromosome doubling. Of that number eight DH lines showed morphological aberrations and/or reduced vigour that made them unfit to be grown in the field. The remaining 43 DH lines were grown in 2001 under regular flue-cured tobacco management and evaluated for principal growth indicators, yield, curability and gross money returns from unit area. In 2002, the evaluation was scaled down to include 13 best performing DH lines of 2001. The DH lines showed a considerable variation for basic growth parameters. Usually, the DH lines had more leaves but were shorter than the parental genotype mostly due to shorter internodes. The majority of DH lines showed delayed flowering compared to the parental cultivar. Yields of cured leaves varied extensively, some of the DH lines yielding above and some below cv. Wislica. Curability measured as percentage of light (1st to 3rd) grades was generally lower in DH lines compared to that in cv. Wislica. However, because of the high leaf yield some of the DH lines were not inferior to the parental cultivar with respect to money returns from unit area.


2020 ◽  
Vol 80 (03) ◽  
Author(s):  
R. K Khulbe ◽  
A. Pattanayak ◽  
Lakshmi Kant ◽  
G. S. Bisht ◽  
M. C. Pant ◽  
...  

The use of in vivo haploid induction system makes the doubled haploid (DH) technology easier to adopt for the conventional maize breeders. However, despite having played an important role in the initial developmental phases of DH technology, Indian maize research has yet to harvest its benefits. Haploid Inducer Lines (HILs) developed by CIMMYT are being widely used in maize breeding programmes in many countries including India. There, however, is no published information on the efficiency of DH line production using CIMMYT HILs in Indian maize breeding programmes. In the present study, the efficiency of DH production using CIMMYT’s tropically adapted inducer line TAILP1 was investigated with eight source populations including two of sweet corn. The average haploid induction rate (HIR) of TAILP1 was 5.48% with a range of 2.01 to 10.03%. Efficiency of DH production ranged from 0.14 to 1.87% for different source populations with an average of 1.07%. The information generated will be useful for maize breeders intending to use DH technology for accelerated development of completely homozygous lines.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nicole Pretini ◽  
Leonardo S. Vanzetti ◽  
Ignacio I. Terrile ◽  
Guillermo Donaire ◽  
Fernanda G. González

Abstract Background In breeding programs, the selection of cultivars with the highest yield potential consisted in the selection of the yield per se, which resulted in cultivars with higher grains per spike (GN) and occasionally increased grain weight (GW) (main numerical components of the yield). In this study, quantitative trait loci (QTL) for GW, GN and spike fertility traits related to GN determination were mapped using two doubled haploid (DH) populations (Baguette Premium 11 × BioINTA 2002 and Baguette 19 × BioINTA 2002). Results In total 305 QTL were identified for 14 traits, out of which 12 QTL were identified in more than three environments and explained more than 10% of the phenotypic variation in at least one environment. Eight hotspot regions were detected on chromosomes 1A, 2B, 3A, 5A, 5B, 7A and 7B in which at least two major and stable QTL sheared confidence intervals. QTL on two of these regions (R5A.1 and R5A.2) have previously been described, but the other six regions are novel. Conclusions Based on the pleiotropic analysis within a robust physiological model we conclude that two hotspot genomic regions (R5A.1 and R5A.2) together with the QGW.perg-6B are of high relevance to be used in marker assisted selection in order to improve the spike yield potential. All the QTL identified for the spike related traits are the first step to search for their candidate genes, which will allow their better manipulation in the future.


Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 112
Author(s):  
Songshan Liu ◽  
Chenxing Zhang ◽  
Weicong Yang ◽  
Xiang Li ◽  
Lu Hou ◽  
...  

Polyploid breeding is an important strategy for tree improvement because polyploid individuals typically show superior traits, such as improved growth, stress resistance, and superior fruit quality. Artificial induction of chromosome doubling of female gametes is an effective approach to obtain triploid progeny. However, no triploid fruit tree cultivars have been developed using this approach. The objective of this study was to explore the utility of chromosome doubling in female gametes of ‘Maya’ jujube to produce triploid individuals. The temporal relationship between flower bud morphology and the megaspore meiotic stage was studied to guide the optimal timing of colchicine treatment. Colchicine solution was applied to bearing shoots of mature ‘Maya’ jujube trees in a field experiment using two treatment methods (improved cotton leaching and injection method) and three concentrations (0.3%, 0.4%, and 0.5%). The water transport rate of ‘Maya’ jujube shoots was studied using dye solution to judge the effectiveness and timing of the colchicine treatment methods. Two triploids were identified among the progenies from the colchicine-treated shoots. The highest efficiency of triploid production was 3.3% when flower buds of diameter 1.76–2.12 mm were treated with 0.3% colchicine solution for 4 h using an improved cotton leaching method. The ground diameter, plant thorn length, leaf width, leaf area, stomatal length, stomatal width, chlorophyll content, and photosynthetic parameters of one triploid individual were significantly higher than those of diploids of identical parentage at 18 months old. Thus, induction of 2n megaspores is an effective approach to generate triploid jujube. These results are expected to promote and accelerate triploid breeding in fruit trees.


2019 ◽  
Author(s):  
Chenxu Liu ◽  
Yu Zhong ◽  
Xiaolong Qi ◽  
Ming Chen ◽  
Zongkai Liu ◽  
...  

AbstractDoubled haploid breeding technology has been one of the most important techniques for accelerating crop breeding. In compare toin vivohaploid induction in maize, which is efficient and background independent, wheat haploid production by interspecific hybridization pollinated with maize is influenced by genetic background and requires rescue of young embryos. Here, we analyzed the homologues of maize haploid induction geneMTL/ZmPLA1/NLDin several crop species systematically, the homologues are highly conserved in sorghum, millet and wheat etc. Since wheat is a very important polyploidy crop, as a proof of concept, we demonstrated that thein vivohaploid induction method could be extended from diploid maize to hexaploid wheat by knocking out the wheat homologues (TaPLAs). Result showed that double knock-out mutation could trigger wheat haploid induction at ~ 2%-3%, accompanied by 30% - 60% seed setting rate. The performance of haploid wheat individual showed shorter plant, narrower leaves and male sterile. Our results also revealed that knockout ofTaPLA-A andTaPLA-D do not affect pollen viability. This study not only confirmed the function of the induction gene and explored a new approach for haploid production in wheat, but also provided an example that thein vivohaploid induction could be applied in more crop species with different ploidy levels. Furthermore, by combining with gene editing, it would be a fast and powerful platform for traits improvement in polyploidy crops breeding.


Author(s):  
Beat Boller ◽  
David Kopecký

Abstract Background: Heterosis (or hybrid vigor) is the over-performance of a hybrid over its parents in a specific trait or a set of traits. As such, hybrid breeding serves as a tool to efficiently trigger gains in breeding programs. Moreover, hybrids of genetically distant landraces, varieties or even species may become evolutionary successful. In Swiss alpine swards, we observed frequent prevalence of triploid hybrids of Festuca pratensis × F. apennina with outstanding competitiveness relative to their parental species in the sites of sympatric occurrence. Results: Observations of these highly vigorous hybrids prompted the study on their heterosis across various environmental conditions. Phenotypic observations during three years at four locations at different altitudes (from 200 m a.s.l. to 1850 m a.s.l.) have shown significant heterosis for dry biomass production at all sites during the first and second year, and at the mid- and high altitude sites also in the third year. At mid-altitude (1000 m a.s.l.), heterosis increased steadily and reached a maximum of +508 % for annual yield (+626% for a single cut) in the third year. This is by far the highest value of heterosis ever reported for annual dry mass yield of a forage grass. Conclusions: Further utilization of triploid hybrids in forage grass breeding is hampered by their sterility hence a need for vegetative propagation. However, artificial chromosome doubling of triploids to create fertile hexaploids, or seeking ways to propagate them vegetatively at an industrial scale might overcome this limitation.


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