EP-4736634-A1 - CONTROL OF HEADING IN CEREALS BY MOWING

EP4736634A1EP 4736634 A1EP4736634 A1EP 4736634A1EP-4736634-A1

Abstract

The present invention relates to a method for field cultivation comprising one or more areas with designated male cereal plants (male areas) and one or more areas with designated male-sterile female cereal plants (female areas), said method comprising the step of passing, during the stem elongation stage of the designated male plants, a cutting tool over at least part of each of said one or more male areas, but not over one or more female areas, to cut designated male cereal plants in said part of each of said one or more male areas. The present invention further relates to a field comprising one or more areas with designated male cereal plants and one or more areas with designated male-sterile female cereal plants, wherein the designated male plants in at least part of each male area were cut with a cutting tool during the stem elongation stage and wherein the designated female plants were not cut during the stem elongation stage. Moreover, the present invention relates to the use of a cutting tool for selectively cutting designated male cereal plants.

Inventors

Moreau, Julien
Delemme, Romain

Assignees

BASF SE

Dates

Publication Date: 20260506
Application Date: 20241031

Claims (15)

A method for cultivating a field comprising one or more areas with designated fertile male cereal plants (male areas) and one or more areas with designated male-sterile female cereal plants (female areas), said method comprising the step of passing, during the stem elongation stage of the designated male plants, a cutting tool over at least a part of each of said one or more male areas, but not over one or more female areas, to cut the designated male cereal plants in said part of each of said one or more male areas.
The method of claim 1, wherein said cereal is wheat, barley, triticale or rye, such as winter wheat.
The method of any one of claims 1 or 2, wherein the designated male cereal plants are in the one-node stage (Zadoks stage 31), two-node stage (Zadoks stage 32) or three-node stage (Zadoks stage 33), in particular the designated male cereal plants are in the one-node stage (Zadoks stage 31) or two-node stage (Zadoks stage 32).
The method of any one of claims 1 to 3, wherein the cutting step delays the heading of the cut designated male plants as compared to uncut control plants by about two to six days, such as by about two to four days.
The method of any one of claims 1 to 4, wherein the cutting step removes the developing spike of the main tiller from at least a portion of the plants over which the cutting tool is passed.
The method of any one of claim 1 to 5, wherein the cutting is at a height which is equal to or slightly below the average aboveground height of the developing spikes of the main tillers.
The method of claim 6, wherein the cutting height is below the average aboveground height of the developing spikes of the main tillers, but above the height of the developing spikes of the secondary tillers, so that most secondary spikes are not cut.
The method of any one of claims 1 to 7, wherein the cutting tool removes most of the developing spikes on the main tillers of the plants over which the tool is passed, but does not remove most of the developing spikes of the secondary tillers.
The method of any one of the preceding claims, wherein the average aboveground height of the developing spikes of the main tillers of the designated male cereal plants is at least 4 cm.
The method of any one of the preceding claims, wherein the method comprises prior to the cutting step a step of determining the average aboveground height of the developing spikes of the main tillers of the designated male cereal plants to set the cutting height at which the cutting tool cuts the designated male cereal plants, and said determination of the average aboveground height comprises: i)measuring the distance from the a) lower end of the crown to b) the upper end of the developing spike in a transversal cut through the main stem of at least five male plants, in particular at least ten male plants, and ii)determining the average aboveground height by calculating the average of the distances measured in step i).
The method of any one of the preceding claims, wherein : i) the cutting tool is passed only over a part of each of said male areas, and wherein said part is the part adjacent to a female area, or ii) the cutting tool is a mechanical mowing machine, such as a lawn mower or a mechanical reaping machine, or iii) the debris that results from the cutting step is not removed, and wherein optionally the debris is mulched, or iv) the designated male plants are removed or destroyed before they set seed, or v) the cutting height is set at 5-7 cm when the measured aboveground height of the spike on the main tiller is 5-7 cm.
The method of any one of the preceding claims, wherein : • the heading of the designated male cereal plants is delayed as compared to corresponding control plants that were not subjected to the cutting step, • the flowering window of the designated male cereal plants is enlarged, • the heading of the designated male cereal plants and the designated male cereal plants is synchronized, and/or • the seed yield of said field is increased as compared to a corresponding control field that was not subjected to the cutting step.
The method of any one the preceding claims, wherein the designated male cereal plants are responsive to gibberellic acid and are treated with gibberellic acid that increases the height of said plants, particularly the cut male plants.
A field comprising one or more areas with designated male cereal plants and one or more areas with designated male-sterile female cereal plants, wherein the designated male plants in at least part of each male area were cut with a cutting tool during the stem elongation stage and wherein the designated female plants were not cut during the stem elongation stage.
Use of a cutting tool for selectively cutting designated male cereal plants during the stem elongation stage that are grown on a field, said field comprising one or more areas with designated male cereal plants and one or more areas with designated male-sterile female cereal plants.

Description

Technical Field The present invention relates to a method for field cultivation comprising one or more areas with designated male cereal plants (male areas) and one or more areas with designated female cereal plants (female areas), said method comprising the step of passing, during the stem elongation stage of the designated male plants, a cutting tool over at least a part of each of said one or more male areas, but not over one or more female areas, to cut designated male cereal plants in said part of each of said one or more male areas.. The present invention further relates to a field comprising one or more areas with designated male cereal plants and one or more areas with designated female cereal plants, wherein the designated male plants in at least part of each male area were cut with a cutting tool during the stem elongation stage and wherein the designated female plants were not cut during the stem elongation stage. Moreover, the present invention relates to the use of a cutting tool for selectively cutting designated male cereal plants. Background art Hybrid cultivars with improved agronomic traits are widely used for the production of plants with increased yield. For wheat, the most widely grown crop in the world, a large scale adoption of the hybrid technology has yet to come. Wheat is a strict self-pollinating crop, with a very low probability of cross-pollination. The self-pollinating nature of wheat makes hybrid production difficult and labor-intensive, as it requires an efficient cross-pollination that overcomes the self-pollination. The same applies to other cereal plants, such as barley, rye, or triticale. Usually, the cross-pollination is achieved by using male-sterile maternal plants that are planted in close proximity to paternal plants. Then, the male plants are allowed to cross-pollinate the male sterile female plants and the female plants will produce hybrid seed. Male sterile plants can be generated, e.g., by using cytoplasmic or genic male sterility systems or by chemical agents that selectively interfere with pollen development (using a CHA or chemical hybridization agent). Hybrid seed production based on cytoplasmic male sterility (CMS) frequently uses a system of three different lines. The first line (line A) is the (cytoplasmic) male-sterile female parent. The second line (line B) is isogenic to line A, except that line B has fertile cytoplasm. Line B is frequently also referred to as "maintainer line" as the cross between line A and line B plants allows for maintaining the A line. The third line (line R, restorer line) provides the male parent for hybrid seed production. It carries one or more fertility-restoring (Rf) genes which are able to restore male fertility. For hybrid seed production, plants of line R are crossed with plants of line A to produce hybrid seed. Genic male sterility (GMS), frequently also referred to as nuclear male sterility (NMS), can result from mutations in genes controlling pollen and/or stamen development. GMS is caused by nuclear genes alone, mostly by recessive alleles (ms). For wheat, the MS1, MS5, MS9, MS22, MS26, and MS45 have been described as male sterility genes. Male fertility restorer genes are capable of restoring the male sterility. Nevertheless, cross-pollination of some cereal plants, such as of wheat or of barley, is still challenging. One way to achieve cross-pollination is by interplanting male and female plants in a mixed stand within centimeters of each other in the same rows (WO 2012/038350 A1, WO2015/135940 A1). However, in such a system it is not possible to harvest only the seeds from female parents. The male parent will produce inbred seed due to self-pollination. Thus, the harvested seeds contain a mixture of hybrid seed and inbred seed. If cross-pollination is not good, then high amounts of selfed male seed will be present in the harvested hybrid seed. Since this may not comply with regulatory requirements and reduces product quality/purity, wheat hybrid seed is typically produced by sowing the male and female plants in separate areas (sometimes referred to as strip planting or "bay-planting system"). The male areas contain the male pollinator plants and are in separate rows from the female areas which contain the male sterile female plants. The areas are separated to such a distance that still allows the pollination of the male sterile female plants by the pollen of the male plants and that seeds from the female plants can be harvested separately. Accordingly, the harvested seeds consist essentially of hybrid seeds (with only a low proportion of inbred seeds). Moreover, cross-pollination is challenging because wheat flowers for a short time only. Therefore, it is advantageous to have synchrony between the pollen shedding of the male parent and the flowering of the female parent. In crop species planted in the spring, synchronization, i.e. alignment of flower timing between two parents, can be achieved by seeding male and fe