IN-VIVO DOUBLED HAPLOID TECHNOLOGY IN MAIZE BREEDING

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.

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R1-nj expression in parental inbreds as a predictor of amenability of maize hybrids to R1-nj-based doubled haploid development

Indian Journal of Genetics and Plant Breeding (The) ◽

10.31742/ijgpb.79.4.5 ◽

2020 ◽

Vol 79 (04) ◽

Author(s):

R. K. Khulbe ◽

A. Pattanayak ◽

Vivek Panday

Keyword(s):

Doubled Haploid ◽

Current Method ◽

Distinct Pattern ◽

Complex Nature ◽

Maize Breeding ◽

Early Maturity ◽

Haploid Inducer ◽

Source Populations ◽

Phenotype Expression

The current method of doubled haploid (DH) development in maize involves in vivo production of haploids using R1-njbased haploid inducer lines that upon use as male render a small fraction of seed in the pollinated female ears haploid. Identification of haploid seed relies on R1-nj marker expression in the endosperm and embryo, and the degree of its expression determines efficiency of DH development process. In the present study, R1-nj expression in the endosperm was characterized in crosses of CIMMYT’s R1-nj-based haploid inducer TAILP1 with a set comprising 18 early maturity hybrids and their 23 parental inbreds. Kernel colour inhibition was observed only in a small proportion of the hybrids and inbreds. Comparison of R1-nj expression in the hybrids and their parental inbreds revealed a distinct pattern, which may be useful in identifying source populations and/or determining parental constituents for synthesizing source populations with predicted amenability to doubled haploid development using R1-nj-based haploid inducers. However, deviation from the pattern was noted in hybrids involving inbreds with higher degree of colour inhibition, which suggests complex nature of R1-nj phenotype expression and necessitates further investigation involving larger sets of germplasm for dissecting the role of maternal and paternal genetic factors in determining R1-nj phenotype expression. The hybrids found exhibiting complete kernel anthocyanin expression in present study can be used directly as source populations for DH development using R1-nj based haploid inducers. Besides, since the inbreds used in the study have originated from and/or are accessible to CGIAR/NARS maize breeding programmes, the information on their kernel anthocyanin expression can be helpful in selection of source populations or generating new source populations amenable for DH development using R1-nj based haploid inducers.

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Doubled haploid technology for line development in maize: technical advances and prospects

Theoretical and Applied Genetics ◽

10.1007/s00122-019-03433-x ◽

2019 ◽

Vol 132 (12) ◽

pp. 3227-3243 ◽

Cited By ~ 14

Author(s):

Vijay Chaikam ◽

Willem Molenaar ◽

Albrecht E. Melchinger ◽

Prasanna M. Boddupalli

Keyword(s):

Doubled Haploid ◽

Chromosome Doubling ◽

Production Costs ◽

Great Promise ◽

Success Rates ◽

Haploid Induction ◽

Maize Breeding ◽

Breeding Programs ◽

Line Production

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.

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Improvement of effectiveness in maize breeding

Acta Agronomica Hungarica ◽

10.1556/aagr.54.2006.3.10 ◽

2006 ◽

Vol 54 (3) ◽

pp. 351-358 ◽

Cited By ~ 2

Author(s):

P. Pepó

Keyword(s):

Recurrent Selection ◽

Genetic Manipulation ◽

Field Testing ◽

Tissue Cultures ◽

Maize Breeding ◽

Breeding Programmes ◽

Speed Up ◽

Selection For

Plant regeneration via tissue culture is becoming increasingly more common in monocots such as maize (Zea mays L.). Pollen (gametophytic) selection for resistance to aflatoxin in maize can greatly facilitate recurrent selection and the screening of germplasm for resistance at much less cost and in a shorter time than field testing. In vivo and in vitro techniques have been integrated in maize breeding programmes to obtain desirable agronomic attributes, enhance the genes responsible for them and speed up the breeding process. The efficiency of anther and tissue cultures in maize and wheat has reached the stage where they can be used in breeding programmes to some extent and many new cultivars produced by genetic manipulation have now reached the market.

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Optimization of chromosome doubling treatment for efficient in vivo doubled haploid production in maize

Israel Journal of Plant Sciences ◽

10.1163/22238980-bja10020 ◽

2021 ◽

pp. 1-10

Author(s):

Sourbh Kumar ◽

Uttam Chandel ◽

Satish Kumar Guleria

Keyword(s):

Doubled Haploid ◽

Seed Set ◽

Chromosome Doubling ◽

Pollen Viability ◽

Haploid Inducer ◽

Haploid Production ◽

Maize Genotypes ◽

Different Doses

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.

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In vitro and in vivo screening for cold tolerance in winter × spring wheat-derived doubled haploids following the wheat × maize system

Acta Agronomica Hungarica ◽

10.1556/aagr.55.2007.3.2 ◽

2007 ◽

Vol 55 (3) ◽

pp. 273-282

Author(s):

S. Sharma ◽

H. Chaudhary

Keyword(s):

Grain Yield ◽

Cold Tolerance ◽

Spring Wheat ◽

Doubled Haploid ◽

Tetrazolium Chloride ◽

Cold Tolerant ◽

Dh Lines ◽

Ttc Test

Seventy-eight doubled haploid (DH) lines, derived from 21 elite and diverse winter × spring wheat F 1 hybrids, following the wheat × maize system, were screened along with the parental genotypes under in vitro and in vivo conditions for cold tolerance. Under in vitro conditions, the 2,3,5-triphenyl tetrazolium chloride (TTC) test was used to characterize the genotypes for cold tolerance. Based on the TTC test, only one doubled haploid, DH 69, was characterized as cold-tolerant, seven DH and five winter wheat parents were moderately tolerant, while the rest were susceptible. Analysis of variance under in vivo conditions also indicated the presence of sufficient genetic variability among the genotypes (DH lines + parents) for all the yield-contributing traits under study. The correlation and path analysis studies underlined the importance of indirect selection for tillers per plant, harvest index and grains per spike in order to improve grain yield. It was also concluded that selection should not be practised for grain weight per spike as it would adversely affect the grain yield per plant. When comparing the field performance of the genotypes with the in vitro screening parameters, it was concluded that in addition to the TTC test, comprising a single parameter, other physiological and biochemical in vitro parameters should be identified, which clearly distinguish between cold-tolerant and susceptible genotypes and also correlate well with their performance under field conditions.

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Optimization of Cucumber Doubled Haploid Line Production Using In Vitro Rescue of In Vivo Induced Parthenogenic Embryos

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.130.4.555 ◽

2005 ◽

Vol 130 (4) ◽

pp. 555-560 ◽

Cited By ~ 14

Author(s):

Elisabet Claveria ◽

Jordi Garcia-Mas ◽

Ramon Dolcet-Sanjuan

Keyword(s):

Flow Cytometry ◽

Doubled Haploid ◽

Chromosome Doubling ◽

Doubled Haploid Line ◽

High Rate ◽

Limiting Factors ◽

Line Production ◽

Haploid Plants

Homozygous doubled haploid lines (DHLs) from new cucumber (Cucumis sativus L.) accessions could be useful to accelerate breeding for resistant varieties. DHLs have been generated by in vitro rescue of in vivo induced parthenogenic embryos. The protocol developed involves the following: 1) induction of parthenogenic embryos by pollinating with pollen irradiated with a Co60 γ-ray source at 500 Gy; 2) in vitro rescue of putative parthenogenic embryos identified by their morphology and localized using a dissecting scope or X-ray radiography; 3) discrimination of undesirable zygotic individuals from the homozygous plants using cucumber and melon SSR markers; 4) determination of ploidy level from homozygous plants by flow cytometry; 5) in vitro chromosome doubling of haploids; and 6) acclimation and selfing of selected lines. Codominant markers and flow cytometry confirmed the gametophytic origin of plants regenerated by parthenogenesis, since all homozygous lines were haploids. No spontaneous doubled haploid plants were rescued. Chromosome doubling of haploid plants was accomplished by an in vitro treatment with 500 μm colchicine. Rescue of diploid or chimeric plants was shown by flow cytometry, prior to their acclimation and planting in the greenhouse. Selfing of colchicine-treated haploid plants allowed for the perpetuation by seed of homozygous lines. The high rate of seed set, 90% of the lines produced seed, facilitated the recovery of inbred lines. Despite some limiting factors, parthenogenesis is routinely used in a cucumber-breeding program to achieve complete homozygosity in one generation. Breeding for new commercial hybrid cultivars will be accelerated. DHLs are ideal resources for genomic analyses.

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Breeding Maize Maternal Haploid Inducers

Plants ◽

10.3390/plants9050614 ◽

2020 ◽

Vol 9 (5) ◽

pp. 614

Author(s):

Henrique Uliana Trentin ◽

Ursula K. Frei ◽

Thomas Lübberstedt

Keyword(s):

Poor Performance ◽

High Price ◽

Small Scale ◽

Maize Breeding ◽

Breeding Programs ◽

Line Production ◽

Dh Lines ◽

Haploid Embryos ◽

The Cost

Maize doubled haploid (DH) lines are usually created in vivo, through crosses with maternal haploid inducers. These inducers have the inherent ability of generating seeds with haploid embryos when used to pollinate other genotypes. The resulting haploid plants are treated with a doubling agent and self-pollinated, producing completely homozygous seeds. This rapid method of inbred line production reduces the length of breeding cycles and, consequently, increases genetic gain. Such advantages explain the wide adoption of this technique by large, well-established maize breeding programs. However, a slower rate of adoption was observed in medium to small-scale breeding programs. The high price and/or lack of environmental adaptation of inducers available for licensing, or the poor performance of those free of cost, might explain why smaller operations did not take full advantage of this technique. The lack of adapted inducers is especially felt in tropical countries, where inducer breeding efforts are more recent. Therefore, defining optimal breeding approaches for inducer development could benefit many breeding programs which are in the process of adopting the DH technique. In this manuscript, we review traits important to maize maternal haploid inducers, explain their genetic basis, listing known genes and quantitative trait loci (QTL), and discuss different breeding approaches for inducer development. The performance of haploid inducers has an important impact on the cost of DH line production.

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