US 20060218679A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2006/0218679 A1 Bernuetz (43) Pub. Date: Sep. 28, 2006 (54) METHOD OF PRODUCING EUPHORBIA (30) Foreign Application Priority Data INTERSPECIFIC HYBRIO PLANTS BY CUTTING AND THEN CULTURING THE Oct. 9, 2003 (AU)...................................... 20O3905549 HYBRIDEMIBRYOS Publication Classification (75) Inventor: Andrew Bernuetz, Silverdale (AU) (51) Int. Cl. AOIH II/00 (2006.01) Siko S. viiserieAU, P.A. (52) U.S. Cl. ........................................ 800/295; 47/58.1 R 900 SECOND AVENUE SOUTH (57) ABSTRACT SUTE 82O MINNEAPOLIS, MN 55402 (US) A method for producing an interspecific hybrid Euphorbia plant. The method comprises: (a) providing a first plant (73) Assignee: Bonza Botanicals Pty Limited, Winma- which is a Euphorbia pulcherrima plant and a second plant lee (AU) which is a species of Euphorbia selected from the group consisting of Euphorbia Cornastra, Euphorbia radians, (21) Appl. No.: 11/402,370 Euphorbia colorata and Euphorbia fulgens, (b) pollinating a flower of the second plant with pollen from the first plant (22) Filed: Apr. 7, 2006 or a flower of the first plant with pollen from the second plant in a manner which permits formation of an embryo in Related U.S. Application Data at least one ovule of the pollinated plant; (c) cutting the embryo, and (d) culturing the cut embryo by placing the cut (63) Continuation of application No. PCT/AU04/00257, embryo in contact with culture medium to permit growth of filed on Feb. 27, 2003. the embryo to thereby produce a primary plant. Patent Application Publication Sep. 28, 2006 US 2006/0218679 A1 Figure 1 US 2006/0218679 A1 Sep. 28, 2006 METHOD OF PRODUCING EUPHORBA SUMMARY OF THE INVENTION INTERSPECIFIC HYBRIO PLANTS BY CUTTING AND THEN CULTURING THE HYBRIDEMIBRYOS 0006 The inventor has found that by using a method in which the embryo is cut and the cut portions placed in FIELD OF THE INVENTION culture, the efficiency of viable plants generated from an 0001. The present invention relates to Euphorbia inter interspecific hybrid embryo developed by hybridising specific hybrid plants and methods for making the same. In Euphorbia pulcherrima with other Euphorbia species can be particular, the invention relates to interspecific hybrid plants improved. derived from the cross between Euphorbia pulcherrima and 0007. In a first aspect, the invention provides a method species of Euphorbia other than Euphorbia pulcherrima, for producing an interspecific hybrid Euphorbia plant com and methods for the generation of interspecific variants with prising: altered characteristics to Euphorbia pulcherrima and other plants. 0008 (a) providing a first plant which is a Euphorbia pulcherrima plant and a second plant which is a species of BACKGROUND OF THE INVENTION Euphorbia selected from the group consisting of Euphorbia 0002. A characteristic of some plants is the ability to cornastra, Euphorbia radians, Euphorbia colorata and cross with different species, called interspecific hybridisa Euphorbia fulgens, tion. This results in the transfer of genetic material between 0009 (b) pollinating a flower of the second plant with the species, leading to the production of an entirely new pollen from the first plant or a flower of the first plant with species of plant. Through the transfer of desirable genetic pollen from the second plant in a manner which permits traits, it is possible to obtain improved species of plants formation of an embryo in at least one ovule of the polli which combine the desirable features of each of the parent nated plant; plants. Interspecific hybridisation thus represents a method for producing new species of plants in which the desirable 0010 (c) cutting the embryo; and features of different species are combined. 0011 (d) culturing the cut embryo by placing the cut 0003. However, not all species of plants are capable of embryo in contact with culture medium to permit growth of undergoing interspecific hybridisation, and the ability of a the embryo to thereby produce an interspecific hybrid plant to be hybridised with a different species can vary Euphorbia plant (a primary plant). widely, depending on the species, the chromosome number 0012 Preferably, a flower of the first plant is pollinated of the plant, and the level of homology between the plant with pollen from the second plant. In other words, preferably species to be crossed. a flower of a Euphorbia pulcherrima plant is pollinated with 0004 Interspecific hybridisation would be desirable pollen from a plant selected from the group consisting of between species within the genus Euphorbia. Euphorbia Euphorbia cornastra, Euphorbia radians, Euphorbia colo comprises a vast number of species. Among these, Euphor rata and Euphorbia filgens. bia pulcherrima, also known as poinsettia, is among the 0013 The cutting step may comprise slicing the embryo most popular of ornamental potted plants. It would be into at least two portions. The term “cutting includes desirable to be able to cross other species of Euphorbia with slicing, splitting, breaking, or any other act that separates the Euphorbia pulcherrima to retain the desirable characteris embryo into at least two portions. Preferably, the portions tics of E. pulcherrima while also inheriting the desirable are roughly equal portions. characteristics of other Euphorbia species. Features such as flowering period, flower colour, branch length, plant height, 0014. In one embodiment, the embryo is cut while con branch internode length etcetera may then be improved in tained in the ovule. In a preferred embodiment, the ovule is the new species to provide a more desirable ornamental at least 3 millimetres in length. The ovule may be sliced plant. transverse to the longitudinal axis, or along the longitudinal axis. Preferably, the ovule is sliced along the longitudinal 0005 Methods for generating interspecific hybrids axis of the ovule. between Euphorbia species have met with limited success. For example, interspecific hybridisation has been possible to 0015 Typically, the sliced ovule containing the sliced a limited extent between the poinsettia Euphorbia pulcher embryo is placed in contact with the culture medium. rima and Euphorbia cornastra as described in WO 0016 Preferably, the culturing step employs ovule slice 02/32217. This document discloses an interspecific hybrid culture. Euphorbia plant that was obtained using embryo rescue following pollination of Euphorbia pulcherrima with 0017. In another embodiment, the embryo is cut follow Euphorbia cornastra. Embryo rescue involves growing the ing excision from the ovule. For example, the embryo may embryo to a globular shaped stage of development following be cut following embryo rescue. Preferably, the embryo is pollination, completely excising the embryo (and Suspensor excised from an ovule that is at least 3 millimetres in length. cells) from the ovary, and Subsequently culturing the embryo 0018. In one embodiment, the method comprises the in vitro. However, many of the embryos that are excised further steps of: during embryo rescue do not survive, and/or do not grow into plants in culture. Further, generally it is not possible to 0019 (a) obtaining a cutting from the primary plant; produce more than one plant from a single embryo using embryo rescue. As a consequence, embryo rescue is often 0020 (b) incubating the cutting under conditions suffi inefficient and/or unsuccessful for use in crosses between cient to propagate the primary plant. Euphorbia species. 0021 Preferably, the cutting is a shoot. US 2006/0218679 A1 Sep. 28, 2006 0022. The cutting may be treated to induce root forma 0036) The mutated plant, or a portion of the mutated tion. For example, root formation may be induced by plant, may be propagated by: treating the cutting with a composition containing a hor mone capable of inducing root formation. Preferably, the 0037 (a) obtaining a bract from the mutated plant; hormone is an auxin. Examples of Suitable auxins include 0038 (b) placing the bract in a solution capable of indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and disinfesting the bract; C.-napthalene acetic acid (NAA). 0039 (c) washing the bract; and 0023. A free-branching agent may be transmitted to the 0040 (d) cultivating the bract to thereby produce a propa primary plant to provide the primary plant with a free gated mutated plant. branching phenotype. Thus, in one embodiment, the method 0041) Preferably, the solution capable of disinfesting the of the invention comprises the further step of transmitting a bract is bleach. The bleach (NaOCl) is preferably used at a free-branching agent to the primary plant. The free-branch concentration of between 1% and 3. ing agent may be transmitted to the primary plant by any means. For example, the free branching agent may be 0042. The primary plant, or a portion of the primary transmitted to the primary plant by a dodder (a parasitic plant, may be propagated by: plant), by a leafhopper insect or by a graft. 0043 (a) obtaining a bract from the primary plant; 0024 Preferably, the free-branching agent is transmitted 0044 (b) placing the bract in a solution capable of to the primary plant by: disinfesting the bract; 0.025 (a) providing a free-branching plant having a free 0045 (c) washing the bract; and branching agent; 0046 (d) cultivating the bract to thereby propagate the 0026 (b) cutting the primary plant and the free-branching primary plant. plant to expose tissue of the plant; 0047 Preferably, the solution capable of disinfesting the 0027 (c) making a graft union between the tissue of the bract is bleach. The bleach (NaOCl) is preferably used at a free-branching plant and the primary plant, whereby at least concentration of between 1% and 3%. one characteristic of a vegetative shoot arising from said 0048. In a second aspect, the invention provides a plant graft is different from the free-branching plant and the produced according to the method of the first aspect of the primary plant; and invention.