For maize, the widely used induction technique is in vivo induction of maternal haploids mureseanu et al 20. Morphological, cellular and molecular evidences reveal that complete or partial chromosome elimination from inducer hzi1 controls the maize in vivo haploid induction. The dh technology in maize breeding, based on in vivo haploid induction. The doubled haploid dh technology has become an important tool for line development in modern maize breeding. Maternal haploid inducers with high haploid induction rates were developed in both temperate and tropical genetic backgrounds making largescale induction of haploids possible from diverse maize germplasm in a coste cient manner 2,5,6. Recently, haploid inducer lines have also been created in arabidopsis thaliana, brassica juncea and maize by the use of engineered centromeric histone 3 cenh3 variants. Optimization of doubled haploid production in maize iowa state. However, distinguishing haploid h from diploid crossing c seeds is problematic for many germplasms due to poor expression or suppression of the currentlyused r1nj embryo marker. In vivo haploid induction has become a routine tool for rapid line development in maize. Identification of in vivo induced maternal haploids in. Producing haploid plants in vivo has become a routine process and has been. In a recent quantitative trait locus qtl mapping study on the in vivo haploid induction rate hir in maize prigge et al.
Maternal haploid induction depends primarily on the inducer used as a. For in vivo production of doubled haploid dh lines in maize, the rate of haploid induction is of crucial importance. Investigation new insights into the genetics of in vivo induction of maternal haploids, the backbone of doubled haploid technology in maize vanessa prigge,,1 xiaowei xu,1 liang li, raman babu, shaojiang chen, gary n. However, the molecular mechanisms underlying hi in maize are still unclear. To investigate the genetic basis of hi, we developed a. In this method, the maize chromosomes are completely eliminated during the early development of the hybrid seeds after wheat spikes were pollinated with maize pollen.
Abstract in vivo haploid induction in maize can be triggered in high frequencies by pollination with special genetic stocks called haploid inducers. The genetic basis of haploid induction in maize identified. Genetic dissection of maternal influence on in vivo haploid induction. Although the gene underlying haploid induction, mtlzmpla1nld, was cloned recently, the mechanism.
In vivo haploid induction based on maternal haploid inducers is the first step in deriving completely homozygous maize doubled haploid dh lines. However, distinguishing haploid h from diploid crossing c seeds is problematic for many. Haploid induction rate hir is influenced by both pollen parent inducing haploidy and the maternal source germplasm used in induction crosses. Genetic dissection of haploid male fertility in maize zea. Mapping of qtl for kernel abortion caused by in vivo. The doubledhaploid dh technology has become an important tool for line development in modern maize breeding.
Haploids were obtained from all maternal genotypes involved in the experiment, including dent, flint and flint. A scientific explanation of the doubled haploid dh technique, including a step by step guide for the creation of a dh line. In vivo haploid induction in maize, tag theoretical and. The mechanism of maternal in vivo haploid induction is not fully understood. Identification of haploid seeds by their oil content. After pollinating the source germplasm with pollen of current inducers, a fraction of 8 to 10% of the developing. Gametophytic and zygotic selection leads to segregation distortion through in vivo induction of a maternal haploid in maize. Production of double haploid plants using in vivo haploid. However, distinguishing haploid h from diploid crossing c seeds is problematic for many germplasm due to poor expression or suppression of the. Morphological, cellular and molecular evidences of chromosome random elimination in vivo upon haploid induction in maize. Doubled haploids can be produced in vivo or in vitro zhang et al.
Fertilization and uniparental chromosome elimination. Improving the e chromosomal doubling of maize haploids. Large scale haploid induction in maize for doubled haploid dh line production is based on an in vivo method 3,4, which. Gametophytic and zygotic selection leads to segregation. Two types of in vivo haploid induction can be differentiated in maize, and will lead to maternal and paternal haploids, respectively. Doubled haploid breeding technology has been one of the most important techniques for accelerating crop breeding. Pdf in vivo haploid induction has become a routine tool for rapid line development in maize zea mays l. In conclusion, we suggest that haploids and dhs should widely be used in breeding and research projects. In vivo haploid induction hi in maize has been widely used and demonstrated to be independent of genetic background and to produce haploids efficiently.
The production of maize haploids primarily depends on the use of stock6derived haploid inducer lines. Several genetic studies with segregating populations from noninducer x inducer crosses identified a major qtl, qhir1, on chromosome 1. Derivation of doubled haploid lines in maize through in vivo induction is routinely practiced in multinational commercial maize breeding programs 1,2 and is gaining increasing popularity in the maize breeding programs of the developing world. The subsequent development of maize haploid inducer lines with a higher haploid induction rate hir allowed breeders to generate haploids efficiently. In vivo haploid induction has become a routine tool for rapid line development in maize zea mays l. Melchinger,2 institute of plant breeding, seed science, and population genetics, university of hohenheim, 70593 stuttgart, germany.
We used two mapping populations including 186 and 263 f2. It can be done cheaply in the field and is broadly applicable across all genetic starting material. Haploid induction requires taking pollen from a haploidinducer plant. Identification of in vivo induced maternal haploids in maize using seedling traits. The production of doubled haploid lines consists of three main steps. New insights into the genetics of in vivo induction of. Melchinger,2 institute of plant breeding, seed science, and population genetics, university of hohenheim, 70593 stuttgart. Identification of in vivoinduced haploid seeds in maize based on oil content. In vivo doubledhaploid technology is widely applied in commercial maize breeding programs because of its timesaving and costreducing features. The maternal genotype had a significant influence on the frequency of haploids obtained. These pure inbred lines allow breeders to quickly evaluate new cross combinations.
Two haploid inducing lines, mhi and m741h, were used for the production of maternal haploids. Derivation of doubled haploid lines in maize through in vivo induction is. Management of the ig gene for haploid induction in maize management of the ig gene for haploid induction in maize. Early spontaneous diploidization of maternal maize haploids generated by in vivo haploid induction early spontaneous diploidization of maternal maize haploids generated by in vivo haploid induction wu, penghao. The qtl qhir8 affecting in vivo haploid induction in maize was mapped to a 789 kb region, embryo abortion rate and segregation ratios were analyzed, linkage markers for mas were developed abstract. Morphological, cellular and molecular evidences of. In vivo haploid induction hi triggered by pollination with special intraspecific genotypes, called inducers, is unique to zea mays l. Springer, new york pollination of maize plants with specific genotypes called inducers, which leads to kernels with a haploid embryo and a regular triploid endosperm. The mechanism underlying the in vivo induction of maternal haploid in maize the mechanism underlying the haploid induction by inducer lines remains unclear due to the absence of direct evidence. We developed two new inducer lines, cau b and cau yfp, which contained b chromosomes and cenh3yfp, respectively, to pollinate elite hybrid zd958. Kernel abortion is common phenomenon in vivo haploid induction and closely linked with haploid induction rate, but little information of kernel abortion is available and its genetic basis still unclear. Phospholipase a generates haploid induction in maize dear editor, maize is one of the most important crops in the world and is also an essential raw material for the food, fuel, and fodder industries.
However, the genetic basis of haploid induction remains elusive. In compare to in vivo haploid 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. Extension of the in vivo haploid induction system from. In maize, dh lines are commonly produced by in vivo maternal haploid induction 5,6. Fine mapping of qhir8 affecting in vivo haploid induction. In vivo haploid induction and efficiency of two in. The objective of this study was to determine the in vivo haploid induction ability of three temperate inducers crossed to a diverse set of tropical maize source germplasm under tropical conditions. Dissection of a major qtl qhir1 conferring maternal. Also we can say that haploid induction is a rather complex phenomenon which requires further studies.
The implementation of the doubled haploid method in maize requires the use of. Early spontaneous diploidization of maternal maize. This study was aimed at analyzing the influence of source germplasm on. Haploid embryos are produced in vivo by nonoccurrence of the fusion of male and female gametes. Maydica 50, 275283 abstract in the last three to five years, doubled haploid dh lines have increasingly been used in maizezea mays l. The in vivo haploid induction technique allows breed ers to develop homozygous inbred lines. The limitations of in vitro haploid induction techniques in maize coupled with their requirement to have a good laboratory and skilled staff makes them less efficient methods chidzanga at al 2017. There are two important steps in creating dh lines. From the s 0 plants of these crosses, doubled haploid dh lines may be developed by in vivo haploid induction schmidt 2004. In recent years, wide hybridization between wheat and maize has become a main approach for haploid production in wheat. Genetic dissection of maternal influence on in vivo. Doublehaploid induction speeds up plantbreeding process. In vivo haploid induction leads to increased frequency of.
Three experiments were conducted employing inducers as male parents to pollinate 120 source germplasm in three environments in mexico. Optimum hybrid maize breeding strategies using doubled. However, this haploid induction method has not been reported in plant breeding programs so far. A diallel analysis of a maize donor population response to. In vivo haploid induction and efficiency of two chromosome. Better results were obtained when the authors used manual pollination than. Doubled haploid dh technology based on in vivo haploid induction hi is used to accelerate the efficiency of breeding in modern maize zea mays improvement programs 1.
Single nucleus sequencing reveals spermatid chromosome. The subsequent development of maize haploid inducer lines with a higher haploid induction rate hir allowed breeders to generate haploids efficiently 12,14. Dh production in maize relies on in vivo haploid induction using maternal haploid inducers. The most efficient way to produce doubled haploids in corn is through haploid induction, he adds. New insights into the genetics ofin vivo induction of maternal haploids, the backbone of doubled haploid technology in maize. Dear editor, doubled haploid dh technology substantially accelerates crop breeding process. Naturally occurring in vivo hi in maize is a rare phenomenon first reported in 1959, i. Consequently, in vivo hi has become the preferred mean of producing maize haploids 15, 16. Doubled haploid dh lines are used in maize zea mays l.
Morphological, cellular and molecular evidences of chromosome. Identification of in vivoinduced haploid seeds in maize. Maizehybridsarewidelyusedtoday,andgainofeliteinbredlines is a crucial step for hybrid breeding. Rapid and accurate identification of in vivo induced.
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