Development of a Haploid-Inducer Mediated Genome Editing System for Accelerating 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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Direct Modification of Multiple Gene Homoeologs in Brassica oleracea and Brassica napus Using Doubled Haploid Inducer‐Mediated Genome Editing System

Plant Biotechnology Journal ◽

10.1111/pbi.13632 ◽

2021 ◽

Author(s):

Chao Li ◽

Shifei Sang ◽

MengDan Sun ◽

Jin Yang ◽

YuQin Shi ◽

...

Keyword(s):

Brassica Napus ◽

Brassica Oleracea ◽

Genome Editing ◽

Doubled Haploid ◽

Multiple Gene ◽

Direct Modification ◽

Haploid Inducer

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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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Impact of Spontaneous Haploid Genome Doubling in Maize Breeding

Plants ◽

10.3390/plants9030369 ◽

2020 ◽

Vol 9 (3) ◽

pp. 369 ◽

Cited By ~ 4

Author(s):

Nicholas A. Boerman ◽

Ursula K. Frei ◽

Thomas Lübberstedt

Keyword(s):

Genome Editing ◽

Male Fertility ◽

Gene Pyramiding ◽

Haploid Genome ◽

Systematic Design ◽

Maize Breeding ◽

Genome Doubling ◽

New Methodologies ◽

Marker Assisted Backcrossing ◽

The Impact

Doubled haploid (DH) technology has changed the maize-breeding landscape in recent years. Traditionally, DH production requires the use of chemical doubling agents to induce haploid genome doubling and, subsequently, male fertility. These chemicals can be harmful to humans and the plants themselves, and typically result in a doubling rate of 10%–30%. Spontaneous genome doubling and male fertility of maize haploids, without using chemical doubling agents, have been observed to a limited extent, for nearly 70 years. Rates of spontaneous haploid genome doubling (SHGD) have ranged from less than 5% to greater than 50%. Recently, there has been increased interest to forgo chemical treatment and instead utilize this natural method of doubling. Genetic-mapping studies comprising worldwide germplasm have been conducted. Of particular interest has been the detection of large-effect quantitative trait loci (QTL) affecting SHGD. Having a single large-effect QTL with an additive nature provides flexibility for the method of introgression, such as marker-assisted backcrossing, marker-assisted gene pyramiding, and systematic design. Moreover, it allows implementation of new methodologies, such as haploid-inducer mediated genome editing (HI-edit) and promotion of alleles by genome editing. We believe the use of SHGD can further enhance the impact of DH technology in maize.

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Opportunities and Challenges in Doubled Haploids and Haploid Inducer-Mediated Genome-Editing Systems in Cucurbits

Agronomy ◽

10.3390/agronomy10091441 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1441

Author(s):

Isidre Hooghvorst ◽

Salvador Nogués

Keyword(s):

Genome Editing ◽

Doubled Haploids ◽

Limiting Factors ◽

Efficient Production ◽

Knock Out ◽

The Past ◽

Haploid Inducer ◽

Winter Squash ◽

Parthenogenetic Embryos

Doubled haploids have played a major role in cucurbit breeding for the past four decades. In situ parthenogenesis via irradiated pollen is the preferred technique to obtain haploid plantlets whose chromosomes are then doubled in Cucurbitaceae, such as melon, cucumber, pumpkin, squash and winter squash. In contrast to doubled haploid procedures in other species, in situ parthenogenesis in cucurbits presents many limiting factors which impede efficient production of haploids. In addition, it is very time-consuming and labor-intensive. However, the haploid inducer-mediated genome-editing system is a breakthrough technology for producing doubled haploids. Several reports have described using the CRISPR/Cas9 system in cucurbit species, and although its application has many bottlenecks, the targeted knock-out of the CENH3 gene will allow breeders to obtain haploid inducer lines that can be used to obtain parthenogenetic embryos. In this review, we discuss the progress made towards the development of doubled haploids and haploid inducer genotypes using CRISPR/Cas9 technologies in cucurbit species. The present review provides insights for the application of haploid inducer-mediated genome-editing system in cucurbit species

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Chromosome doubling methods in doubled haploid and haploid inducer-mediated genome-editing systems in major crops

Plant Cell Reports ◽

10.1007/s00299-020-02605-0 ◽

2020 ◽

Cited By ~ 1

Author(s):

Isidre Hooghvorst ◽

Salvador Nogués

Keyword(s):

Genome Editing ◽

Doubled Haploid ◽

Chromosome Doubling ◽

Haploid Inducer

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Rice Haploid Inducer Development by Genome Editing

Methods in Molecular Biology - Rice Genome Engineering and Gene Editing ◽

10.1007/978-1-0716-1068-8_14 ◽

2021 ◽

pp. 221-230

Author(s):

Juntao Liu ◽

Dawei Liang ◽

Li Yao ◽

Ya Zhang ◽

Chunxia Liu ◽

...

Keyword(s):

Genome Editing ◽

Haploid Inducer

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Development of late temperate in vivo haploid inducers

Genetika ◽

10.2298/gensr2101051c ◽

2021 ◽

Vol 53 (1) ◽

pp. 51-64

Author(s):

Rahime Cengiz ◽

Mesut Esmeray

Keyword(s):

Plant Height ◽

Haploid Induction ◽

Maize Breeding ◽

Branch Number ◽

Breeding Programs ◽

Haploid Inducer ◽

Breeding Populations ◽

Ssrs Markers ◽

Maize Research Institute

In vivo doubled haploid technique has been widely used in advanced maize breeding programs due to cost, labor and time advantages and increase in efficiency. However, the number of available inducer lines in the world is sufficient. Six BC1 breeding populations including RWS and RWK-76 haploid inducer lines and late temperate ADK-451, ADK-737 and ADK-455 lines were developed by Sakarya Maize Research Institute (MRI) in Turkey. The RWS and RWK-76 haploid inducer lines were used as donors. Pedigree method was employed to develop the inducer lines. Anthocyanin coloration of plant, tassel length, branch number of tassel, plant height, days to flowering, embryo-endosperm colorfulness and haploid induction rate (HIR) were determined. The genotypes with the best characteristics were selected. The families from BC1F3 to BC1F7 were hybridized to liguleless line to determine the HIR and families with HIR over 8% were selected from BC1 populations. The HIR, plant height and days to tassel flowering values of in-1021 and in-1076 candidate haploid inducer lines were 10.5 and 12.3%, 195 and 200 cm, and 69 and 68 days, respectively. The HIR value of RWS donor haploid inducer ranged from 8.9 to 11.3% and for RWK-76 from 7.3 to 9.8%. Simple Sequence Repeats (SSRs) markers were used to identify genetic similarity between late temperate haploid inducer lines and donors. The similarity rates of in-1021 and in-1076 inducer lines to the RWS donor were 38 and 15%, and to the RWK-76 donor were 23 and 27%. The similarity rate between the two candidate inducer lines was 30%. The results indicated that the late temperate haploid inducer lines developed will increase the efficiency of maize breeding.

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