This disclosure concerns methods for estimating the breeding value of plants for the purpose of producing doubled haploid, for example, to identify selection candidates having high breeding values.

This disclosure concerns methods for estimating the breeding value of plants for the purpose of producing doubled haploid, for example, to identify selection candidates having high breeding values.

The present disclosure provides a method for obtaining adventitious tetraploid buds of Blumea balsamifera, comprising the following steps: selecting a root segment of diploid B. balsamifera as an explant, culturing the root segment in a chromosome doubling inducing medium supplemented with 0.025-0.1 mg/L 1-naphthaleneacetic acid (NAA), 1.0-2.0 mg/L 6-benzylaminopurine (6-BA), and 90-150 mg/L colchicine, inducing explant cells, and simultaneously doubling chromosomes and differentiating the adventitious buds. The present disclosure fills the blank of using a root of B. balsamifera as the explant and increases effective explant sources during the propagation, proliferation and biotechnological breeding of B. balsamifera. More importantly, root cells of the B. balsamifera are directly differentiated into adventitious buds while chromosomes are doubled, and a callus formation process is not needed, so that the technical links are simplified and the variation of regeneration buds and the generation of chimeras are reduced.

The present disclosure provides a method for obtaining adventitious tetraploid buds of Blumea balsamifera, comprising the following steps: selecting a root segment of diploid B. balsamifera as an explant, culturing the root segment in a chromosome doubling inducing medium supplemented with 0.025-0.1 mg/L 1-naphthaleneacetic acid (NAA), 1.0-2.0 mg/L 6-benzylaminopurine (6-BA), and 90-150 mg/L colchicine, inducing explant cells, and simultaneously doubling chromosomes and differentiating the adventitious buds. The present disclosure fills the blank of using a root of B. balsamifera as the explant and increases effective explant sources during the propagation, proliferation and biotechnological breeding of B. balsamifera. More importantly, root cells of the B. balsamifera are directly differentiated into adventitious buds while chromosomes are doubled, and a callus formation process is not needed, so that the technical links are simplified and the variation of regeneration buds and the generation of chimeras are reduced.

Non-transgenic and transgenic plants, preferably crop plants, comprising at least one mutation of the KINTEOCHORE NULL2 (KNL2) protein, especially a mutation causing a substitution of an amino acid within the KNL2 protein, preferably within the C-terminal region of the KNL2 protein, which preferably have the biological activity of a haploid inducer. Further are methods of generating plants and haploid and double haploid plants obtainable by crossing non-transgenic and transgenic plants with wildtype plants as well as methods of facilitating cytoplasm exchange.

Non-transgenic and transgenic plants, preferably crop plants, comprising at least one mutation of the KINTEOCHORE NULL2 (KNL2) protein, especially a mutation causing a substitution of an amino acid within the KNL2 protein, preferably within the C-terminal region of the KNL2 protein, which preferably have the biological activity of a haploid inducer. Further are methods of generating plants and haploid and double haploid plants obtainable by crossing non-transgenic and transgenic plants with wildtype plants as well as methods of facilitating cytoplasm exchange.

The present invention concerns an isolated polynucleotide responsible of haploid induction in maize plants and related processes. Additionally, the invention relates to plants that have been genetically transformed with the polynucleotide of the invention. The invention also relates to a process for screening a mutant plant population for enhanced haploid induction by using said isolated polynucleotide. The invention further relates to molecular markers associated with haploid induction in maize plants and their use in quality control for inducer lines.

Plant cell fate and development is altered by treating cells with cellular reprogramming factors. Embryogenesis inducing morphogenic developmental genes are used as cellular reprogramming factors, specifically comprising polypeptides or polynucleotides encoding gene products for generating doubled haploids or haploid plants from gametes. Maize microspores treated by contacting the isolated cells with an exogenous purified, recombinant embryogenesis inducing morphogenic developmental gene polypeptide results in embryogenesis. The gametes of a maize plant develop into embryoids when transformed with a genetic construct including regulatory elements and structural genes capable of acting in a cascading fashion to alter cellular fate of plant cells. Developmental morphogenic proteins expressed from a genetic construct are used for ex situ treatment methods and for in planta cellular reprogramming.

Plant cell fate and development is altered by treating cells with cellular reprogramming factors. Embryogenesis inducing morphogenic developmental genes are used as cellular reprogramming factors, specifically comprising polypeptides or polynucleotides encoding gene products for generating doubled haploids or haploid plants from gametes. Maize microspores treated by contacting the isolated cells with an exogenous purified, recombinant embryogenesis inducing morphogenic developmental gene polypeptide results in embryogenesis. The gametes of a maize plant develop into embryoids when transformed with a genetic construct including regulatory elements and structural genes capable of acting in a cascading fashion to alter cellular fate of plant cells. Developmental morphogenic proteins expressed from a genetic construct are used for ex situ treatment methods and for in planta cellular reprogramming.

Methods and compositions for improved plant breeding using gene editing and haploid induction are provided.