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. New insights into the genetics of in vivo induction of. Optimum hybrid maize breeding strategies using doubled. Two haploid inducing lines, mhi and m741h, were used for the production of maternal haploids. In recent years, wide hybridization between wheat and maize has become a main approach for haploid production in wheat. In conclusion, we suggest that haploids and dhs should widely be used in breeding and research projects. However, this haploid induction method has not been reported in plant breeding programs so far. Morphological, cellular and molecular evidences of.
Doubled haploid dh lines are used in maize zea mays l. The dh technology in maize breeding, based on in vivo haploid induction. In vivo doubledhaploid technology is widely applied in commercial maize breeding programs because of its timesaving and costreducing features. The subsequent development of maize haploid inducer lines with a higher haploid induction rate hir allowed breeders to generate haploids efficiently 12,14. However, the molecular mechanisms underlying hi in maize are still unclear. However, the genetic basis of haploid induction remains elusive. Optimization of doubled haploid production in maize iowa state. Abstract in vivo haploid induction in maize can be triggered in high frequencies by pollination with special genetic stocks called haploid inducers. In vivo haploid induction and efficiency of two in. Dh production in maize relies on in vivo haploid induction using maternal haploid inducers. In vivo haploid induction based on maternal haploid inducers is the first step in deriving completely homozygous maize doubled haploid dh lines. Single nucleus sequencing reveals spermatid chromosome.
Identification of in vivo induced maternal haploids in. Genetic dissection of maternal influence on in vivo haploid induction. 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. In vivo haploid induction leads to increased frequency of. The doubled haploid dh technology has become an important tool for line development in modern maize breeding. Although the gene underlying haploid induction, mtlzmpla1nld, was cloned recently, the mechanism. Production of double haploid plants using in vivo haploid. Maternal haploid induction depends primarily on the inducer used as a. From the s 0 plants of these crosses, doubled haploid dh lines may be developed by in vivo haploid induction schmidt 2004. There are two important steps in creating dh lines. Haploids were obtained from all maternal genotypes involved in the experiment, including dent, flint and flint. Several genetic studies with segregating populations from noninducer x inducer crosses identified a major qtl, qhir1, on chromosome 1. Maydica 50, 275283 abstract in the last three to five years, doubled haploid dh lines have increasingly been used in maizezea mays l. The production of doubled haploid lines consists of three main steps.
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. In vivo haploid induction has become a routine tool for rapid line development in maize. 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. Melchinger,2 institute of plant breeding, seed science, and population genetics, university of hohenheim, 70593 stuttgart. We used two mapping populations including 186 and 263 f2. The implementation of the doubled haploid method in maize requires the use of. Consequently, in vivo hi has become the preferred mean of producing maize haploids 15, 16. Haploid induction requires taking pollen from a haploidinducer plant. 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. Gametophytic and zygotic selection leads to segregation distortion through in vivo induction of a maternal haploid in maize. Management of the ig gene for haploid induction in maize management of the ig gene for haploid induction in maize.
To investigate the genetic basis of hi, we developed a. Haploid induction rate hir is influenced by both pollen parent inducing haploidy and the maternal source germplasm used in induction crosses. Melchinger,2 institute of plant breeding, seed science, and population genetics, university of hohenheim, 70593 stuttgart, germany. In vivo haploid induction hi triggered by pollination with special intraspecific genotypes, called inducers, is unique to zea mays l. Three experiments were conducted employing inducers as male parents to pollinate 120 source germplasm in three environments in mexico. Genetic dissection of haploid male fertility in maize zea. Better results were obtained when the authors used manual pollination than. Fertilization and uniparental chromosome elimination. Fine mapping of qhir8 affecting in vivo haploid induction. Identification of in vivoinduced haploid seeds in maize based on oil content. In a recent quantitative trait locus qtl mapping study on the in vivo haploid induction rate hir in maize prigge et al. Morphological, cellular and molecular evidences of chromosome. The most efficient way to produce doubled haploids in corn is through haploid induction, he adds.
Mapping of qtl for kernel abortion caused by in vivo. Producing haploid plants in vivo has become a routine process and has been. Doubled haploid breeding technology has been one of the most important techniques for accelerating crop breeding. 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. The mechanism of maternal in vivo haploid induction is not fully understood.
Rapid and accurate identification of in vivo induced. After pollinating the source germplasm with pollen of current inducers, a fraction of 8 to 10% of the developing. Haploid embryos are produced in vivo by nonoccurrence of the fusion of male and female gametes. Identification of in vivoinduced haploid seeds in maize. Improving the e chromosomal doubling of maize haploids. Gametophytic and zygotic selection leads to segregation. Introduction in hybrid maize breeding, new genetic variation is generally generated by crossing two or more elite inbred lines within each heterotic group bernardo 2002. It can be done cheaply in the field and is broadly applicable across all genetic starting material.
Two types of in vivo haploid induction can be differentiated in maize, and will lead to maternal and paternal haploids, respectively. In vivo haploid induction in maize, tag theoretical and. Large scale haploid induction in maize for doubled haploid dh line production is based on an in vivo method 3,4, which. 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. However, distinguishing haploid h from diploid crossing c seeds is problematic for many. The subsequent development of maize haploid inducer lines with a higher haploid induction rate hir allowed breeders to generate haploids efficiently. Also we can say that haploid induction is a rather complex phenomenon which requires further studies. The production of maize haploids primarily depends on the use of stock6derived haploid inducer lines. A diallel analysis of a maize donor population response to. 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. Extension of the in vivo haploid induction system from. A scientific explanation of the doubled haploid dh technique, including a step by step guide for the creation of a dh line.
Identification of haploid seeds by their oil content. The doubledhaploid dh technology has become an important tool for line development in modern maize breeding. The in vivo haploid induction technique allows breed ers to develop homozygous inbred lines. Maizehybridsarewidelyusedtoday,andgainofeliteinbredlines is a crucial step for hybrid breeding. We developed two new inducer lines, cau b and cau yfp, which contained b chromosomes and cenh3yfp, respectively, to pollinate elite hybrid zd958. The maternal genotype had a significant influence on the frequency of haploids obtained. 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. Derivation of doubled haploid lines in maize through in vivo induction is. These pure inbred lines allow breeders to quickly evaluate new cross combinations.
Morphological, cellular and molecular evidences of chromosome random elimination in vivo upon haploid induction in maize. However, distinguishing haploid h from diploid crossing c seeds is problematic for many germplasm due to poor expression or suppression of the. 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. 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. The genetic basis of haploid induction in maize identified. Dissection of the genetic architecture of stalk mechanical. Pdf in vivo haploid induction has become a routine tool for rapid line development in maize zea mays l. For maize, the widely used induction technique is in vivo induction of maternal haploids mureseanu et al 20. 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. In maize, dh lines are commonly produced by in vivo maternal haploid induction 5,6. This study was aimed at analyzing the influence of source germplasm on.
Doublehaploid induction speeds up plantbreeding process. Identification of in vivo induced maternal haploids in maize using seedling traits. In vivo haploid induction and efficiency of two chromosome. Naturally occurring in vivo hi in maize is a rare phenomenon first reported in 1959, i. For in vivo production of doubled haploid dh lines in maize, the rate of haploid induction is of crucial importance. Morphological, cellular and molecular evidences reveal that complete or partial chromosome elimination from inducer hzi1 controls the maize in vivo haploid induction. 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. 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. Dear editor, doubled haploid dh technology substantially accelerates crop breeding process. In vivo haploid induction hi in maize has been widely used and demonstrated to be independent of genetic background and to produce haploids efficiently. Dissection of a major qtl qhir1 conferring maternal.
In vivo haploid induction has become a routine tool for rapid line development in maize zea mays l. 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. New insights into the genetics ofin vivo induction of maternal haploids, the backbone of doubled haploid technology in maize. However, the number of currently available maize haploid inducers is far smaller in comparison. Two haploidinducing lines, mhi and m741h, were used for the production of maternal haploids.
1431 1416 1448 726 498 169 1530 1053 1437 410 1308 716 1095 1192 965 1482 911 1389 258 956 1345 947 1180 222 1305 1328 685 28 1251 657 662 604 282 718 1314 324 1453 555 1494 1468