scholarly journals Selection Gain of Maize Haploid Inducers for the Tropical Savanna Environments

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2812
Author(s):  
Abil Dermail ◽  
Sompong Chankaew ◽  
Kamol Lertrat ◽  
Thomas Lübberstedt ◽  
Khundej Suriharn
Keyword(s):  
Genetic Gain ◽  
Seed Set ◽  
Agronomic Traits ◽  
Phenotypic Diversity ◽  
Hybrid Breeding ◽  
Agronomic Performance ◽  
Tropical Savanna ◽  
Haploid Induction ◽  
Haploid Induction Rate ◽  
Induction Rate

Lacking elite haploid inducers performing high haploid induction rate (HIR) and agronomic performance is one of fundamental factors hindering the rapid adoption of doubled haploid technology in maize hybrid breeding, especially under tropical savanna climate. Breeding haploid inducers for specific agro-ecology, thus, is indispensable yet challenging. We used temperate inducer Stock6 as genetic source for haploid induction ability and eight tropical maize genotypes as principal donors for agronomic adaptation. Three cycles of modified ear-to-row with 5% intra-family selection were applied in a population set of 78 putative haploid inducer families emphasized on agronomic performance, R1-nj anthocyanin intensity, and inducer seed set. Genetic gains, variance components, and heritability on given traits were estimated. Hierarchical clustering based on five selection criteria was performed to investigate the phenotypic diversity of putative families. Cycle effect was predominant for all observed traits. Realized genetic gain was positive for HIR (0.40% per cycle) and inducer seed set (30.10% or 47.30 seeds per ear per cycle). In this study, we reported the first haploid inducers for regions under tropical savanna climate. Three inducer families, KHI-42, KHI-54, and KHI-64, were promising as they possessed HIR about 7.8% or 14 haploid seeds per tester ear and inducer seed rate about 95.0% or 208 inducer seeds per ear. The breeding method was effective for enhancing the seed set and the expression of R1-nj anthocyanin marker of inducers, yet it showed a low effectiveness to improve haploid induction rate. Introgression of temperate inducer Stock6 into tropical gene pool followed by phenotypic selections through modified ear-to-row selection on inducer seed set and R1-nj marker did not compromise the agronomic traits of tropical inducer families. Implications and further strategies for optimizing genetic gain on HIR are discussed.

scholarly journals MYO, a Candidate Gene for Haploid Induction in Maize Causes Male Sterility

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 773
Author(s):  
Kimberly Vanous ◽  
Thomas Lübberstedt ◽  
Rania Ibrahim ◽  
Ursula K. Frei
Keyword(s):  
Male Sterility ◽  
Gene Isolation ◽  
Haploid Induction ◽  
Maize Breeding ◽  
Breeding Programs ◽  
Positional Candidate ◽  
Haploid Induction Rate ◽  
Induction Rate ◽  
Transgenic Lines ◽  
Strong Candidate

Doubled haploid technology is highly successful in maize breeding programs and is contingent on the ability of maize inducers to efficiently produce haploids. Knowledge of the genes involved in haploid induction is important for not only developing better maize inducers, but also to create inducers in other crops. The main quantitative trait loci involved in maize haploid induction are qhir1 and qhir8. The gene underlying qhir1 has been discovered and validated by independent research groups. Prior to initiation of this study, the gene associated with qhir8 had yet to be recognized. Therefore, this research focused on characterizing positional candidate genes underlying qhir8. Pursuing this goal, a strong candidate for qhir8, GRMZM2G435294 (MYO), was silenced by RNAi. Analysis of crosses with these heterozygous RNAi-transgenic lines for haploid induction rate revealed that the silencing of MYO significantly enhanced haploid induction rate by an average of 0.6% in the presence of qhir1. Recently, GRMZM2G465053 (ZmDMP) was identified by map-based gene isolation and shown to be responsible for qhir8. While our results suggest that MYO may contribute to haploid induction rate, results were inconsistent and only showing minor increases in haploid induction rate compared to ZmDMP. Instead, reciprocal crosses clearly revealed that the silencing of MYO causes male sterility.

scholarly journals Development of In Vivo Haploid Inducer Lines for Screening Haploid Immature Embryos in Maize

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 739
Author(s):  
Chen Chen ◽  
Zijian Xiao ◽  
Junwen Zhang ◽  
Wei Li ◽  
Jinlong Li ◽  
...  
Keyword(s):  
Doubled Haploid ◽  
Immature Embryos ◽  
Haploid Induction ◽  
Haploid Induction Rate ◽  
Induction Rate ◽  
Haploid Inducer ◽  
Breeding Populations ◽  
Selection For ◽  
Doubled Haploid Breeding

Doubled haploid technology is widely applied in maize. The haploid inducer lines play critical roles in doubled haploid breeding. We report the development of specialized haploid inducer lines that enhance the purple pigmentation of crossing immature embryos. During the development of haploid inducer lines, two breeding populations derived from the CAU3/S23 and CAU5/S23 were used. Molecular marker-assisted selection for both qhir1 and qhir8 was used from BC1F1 to BC1F4. Evaluation of the candidate individuals in each generation was carried out by pollinating to the tester of ZD958. Individuals with fast and clear pigmentation of the crossing immature embryos, high number of haploids per ear, and high haploid induction rate were considered as candidates. Finally, three new haploid inducer lines (CS1, CS2, and CS3) were developed. The first two (CS1 and CS2) were from the CAU3/S23, with a haploid induction rate of 8.29%–13.25% and 11.54%–15.54%, respectively. Meanwhile, the CS3 was from the CAU5/S23. Its haploid induction rate was 8.14%–12.28%. In comparison with the donor haploid inducer lines, the 24-h purple embryo rates of the newly developed haploid inducer lines were improved by 10%–20%, with a ~90% accuracy for the identification of haploid immature embryos. These new haploid inducer lines will further improve the efficiency of doubled haploid breeding of maize.

scholarly journals PL-4 (CIP596131.4): an Improved Potato Haploid Inducer

2021 ◽  
Author(s):  
Benny Ordoñez ◽  
Monica Santayana ◽  
Mariela Aponte ◽  
Isabelle M. Henry ◽  
Luca Comai ◽  
...  
Keyword(s):  
Genetic Background ◽  
Potato Breeding ◽  
Haploid Induction ◽  
Breeding Lines ◽  
International Potato ◽  
Haploid Induction Rate ◽  
Induction Rate ◽  
Hybrid Seeds ◽  
Efficient Screening ◽  
Potato Genetics

AbstractDihaploid production from elite tetraploid cultivars is key to both traditional and novel breeding approaches that seek to simplify potato genetics. For this purpose, efficient and widely compatible haploid inducers (HIs) are needed. We compared PL-4, a new HI developed at the International Potato Center, to known HIs IvP101 and IvP35. By pollination of elite tetraploid breeding lines, we showed that PL-4 performed significantly better and had a homogeneous response regardless of the genetic background of the pistillate parents, on the most important efficiency traits—number of dihaploids per 100 fruits and haploid induction rate. Moreover, PL-4 exhibited a reduced proportion of hybrid seeds, a convenient trait for efficient screening. In this context, we recommend PL-4 as an enhanced HI for the potato breeding community.

Effect of source germplasm and season on the in vivo haploid induction rate in tropical maize

Euphytica ◽  
2011 ◽  
Vol 180 (2) ◽  
pp. 219-226 ◽  
Author(s):  
Aida Z. Kebede ◽  
Baldev S. Dhillon ◽  
Wolfgang Schipprack ◽  
Jose L. Araus ◽  
Marianne Bänziger ◽  
...  
Keyword(s):  
Tropical Maize ◽  
Haploid Induction ◽  
Haploid Induction Rate ◽  
Induction Rate

Mapping of maternal QTLs for in vivo haploid induction rate in maize (Zea mays L.)

Euphytica ◽  
2013 ◽  
Vol 196 (3) ◽  
pp. 413-421 ◽  
Author(s):  
Penghao Wu ◽  
Haochuan Li ◽  
Jiaojiao Ren ◽  
Shaojiang Chen
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Haploid Induction ◽  
Haploid Induction Rate ◽  
Induction Rate

scholarly journals Genomic prediction of maternal haploid induction rate in maize

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Vinícius Costa Almeida ◽  
Henrique Uliana Trentin ◽  
Ursula Karoline Frei ◽  
Thomas Lübberstedt
Keyword(s):  
Genomic Prediction ◽  
Haploid Induction ◽  
Haploid Induction Rate ◽  
Induction Rate

scholarly journals Sorghum pan-genome explores the functional utility to accelerate the genetic gain

2021 ◽  
Author(s):  
Pradeep Ruperao ◽  
Nepolean Thirunavukkarasu ◽  
Prasad Gandham ◽  
Sivasubramani S. ◽  
Govindaraj M ◽  
...  
Keyword(s):  
Genetic Gain ◽  
Core Genome ◽  
Agronomic Traits ◽  
Crop Improvement ◽  
Genomic Diversity ◽  
Pan Genome ◽  
Genome Association ◽  
Reference Genomes ◽  
Insight Into ◽  
Variable Genes

AbstractSorghum (Sorghum bicolor L.) is one of the most important food crops in the arid and rainfed production ecologies. It is a part of resilient farming and is projected as a smart crop to overcome the food and nutritional challenges in the developing world. The development and characterisation of the sorghum pan-genome will provide insight into genome diversity and functionality, supporting sorghum improvement. We built a sorghum pan-genome using reference genomes as well as 354 genetically diverse sorghum accessions belonging to different races. We explored the structural and functional characteristics of the pan-genome and explain its utility in supporting genetic gain. The newly-developed pan-genome has a total of 35,719 genes, a core genome of 16,821 genes and an average of 32,795 genes in each cultivar. The variable genes are enriched with environment responsive genes and classify the sorghum accessions according to their race. We show that 53% of genes display presence-absence variation, and some of these variable genes are predicted to be functionally associated with drought traits. Using more than two million SNPs from the pan-genome, association analysis identified 398 SNPs significantly associated with important agronomic traits, of which, 92 were in genes. Drought gene expression analysis identified 1,788 genes that are functionally linked to different conditions, of which 79 were absent from the reference genome assembly. This study provides comprehensive genomic diversity resources in sorghum which can be used in genome assisted crop improvement.

scholarly journals Assessing Effect of Marker-Based Improvement of Maize Synthetics on Agronomic Performance, Carotenoid Content, Combining Ability and Heterosis

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1625
Author(s):  
Innocent Iseghohi ◽  
Ayodeji Abe ◽  
Silvestro Meseka ◽  
Wende Mengesha ◽  
Melaku Gedil ◽  
...  
Keyword(s):  
Grain Yield ◽  
Agronomic Traits ◽  
Vitamin A Deficiency ◽  
Inbred Lines ◽  
Provitamin A ◽  
Carotenoid Content ◽  
Agronomic Performance ◽  
Gene Effects ◽  
Additive Gene ◽  
Β Carotene

Vitamin A deficiency (VAD) is a serious problem in sub-Saharan Africa (SSA) and other parts of the world. Understanding the effect of marker-based improvement (MARS) of two maize synthetics (HGA and HGB) representing different heterotic groups on their agronomic performance, carotenoid content, and combining abilities could help identify suitable sources to develop divergent inbred lines for optimizing heterosis. This study involved three selection cycles each of the two synthetics and their nine varietal-cross hybrids together with a released check variety was conducted across four diverse locations in Nigeria in 2018 and 2019. Environment and hybrid effects were significant on grain yield and other agronomic traits as well as provitamin A content and other carotenoids. Genetic improvement per cycle of MARS in the parental synthetics was 15% for provitamin A, 25% for β-carotene and 26% for lutein in HGA and 4% for grain yield, 3% for zeaxanthin and 5% for α-carotene in HGB. Grain yield and agronomic traits of the two maize synthetics were controlled by additive and non-additive gene effects, while provitamin A content and other carotenoids were mainly controlled by additive gene effects. Some selection cycles which were high in grain yield and provitamin A content were identified as potential sources of new and divergent maize inbred lines in maize breeding programs. Some varietal-cross hybrids expressed significant mid-parent heterosis for grain yield and moderate mid-parent heterosis for provitamin A, β-carotene and xanthophylls. These hybrids could be commercialized at reasonable prices to small-scale farmers in rural areas that are most affected by vitamin A deficiency.

scholarly journals The genotypic response towards haploid induction in Turkish onion (Allium cepa L.) germplasm

2020 ◽  
Vol 48 (3) ◽  
pp. 1176-1184
Author(s):  
Faika YARALI KARAKAN
Keyword(s):  
Flow Cytometry ◽  
Allium Cepa ◽  
Ms Medium ◽  
Haploid Induction ◽  
Flower Buds ◽  
Plant Survival ◽  
Survival Percentage ◽  
Induction Rate ◽  
Allium Cepa L ◽  
Medium Flow

Haploid induction efficiency of unpollinated flower buds in twenty-six Turkish onion germplasm were determined on two media, Dunstan and Short medium (BDS) and Murashige and Skoog’s medium (MS). On BDS medium, 5850 flower buds were cultured and the induction rate was 2.10% and a plant survival percentage of 1.62% (2 plants). On MS medium, 5850 flower buds were cultured and 175 plantlets were induced; induction rate was 2.99% and plant survival percentage was 13.71% (24 plants). The highest number of plantlets was obtained from genotype Sanliurfa 2; 27 plantlets on BDS medium while 45 plantlets on MS medium. Flow cytometry confirmed that out of the twenty-six plants, 4 plants were haploid (15.38%), 2 mixoploid (7.69%), 18 (69.23%) diploid and 2 tetraploid (7.69%).

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