WO2014209903A1

WO2014209903A1 - Method for controlled growth and harvesting of pollen

Info

Publication number: WO2014209903A1
Application number: PCT/US2014/043706
Authority: WO
Inventors: Jason Cope
Original assignee: Pioneer Hi Bred International Inc
Current assignee: Pioneer Hi Bred International Inc
Priority date: 2013-06-24
Filing date: 2014-06-23
Publication date: 2014-12-31
Anticipated expiration: 2015-12-24
Also published as: CN105338804A; BR112015031826A2; CA2913485A1

Abstract

Embodiments of a method and apparatus are provided for facilitating the controlled growth and harvesting of pollen. According to the method, tassels are cut from maize plants and placed in growth chambers to allow the tassels to continue to develop at a controlled rate. For example, environmental conditions such as temperature and humidity within the growth chambers may be monitored and regulated. Once the anthers on a tassel begin to release pollen, the growth chamber may be vibrated and/or air may be directed through the growth chamber to encourage further release and collection of pollen on demand. Furthermore, inert materials may be directed with the air to frictionally encourage dehiscence of undehisced anthers.

Description

METHOD FOR CONTROLLED GROWTH AND

HARVESTING OF POLLEN

FIELD OF THE INVENTION

[0001] The present invention relates generally to methods for controlling the growth and maturation of maize tassels and for harvesting pollen from the tassels.

BACKGROUND

[0002] For a variety of reasons, plant species may be intentionally bred. For example, in some applications plant species are intentionally bred to form hybrid plant species. In some applications, hybrid plants are bred to exhibit various desirable traits. Such traits may include, for example, resistance to heat and drought, resistance to disease and insect damage, improved yield characteristics, and improved agronomic quality. In general, plants may be capable of self-pollination, cross- pollination, or both. Self-pollination describes pollination using pollen from one flower that is transferred to the same or another flower of the same plant. Cross- pollination describes pollination using pollen delivered from a flower of a different plant from a different family or line.

[0003] Plants that have been self -pollinated and selected for many generations become homozygous at almost all gene loci and produce a uniform population of true breeding progeny. A cross between two different homozygous lines produces a uniform population of hybrid plants that may be heterozygous for many gene loci. A cross of two plants each heterozygous at a number of gene loci will produce a population of heterogeneous plants that differ genetically and will not be uniform.

[0004] Maize (Zea mays L), often referred to as corn in the United States, can be bred by both self-pollination and cross-pollination techniques. Maize has separate male and female flowers on the same plant. The male flowers are located on the tassel and the female flowers are located on the ear. Natural pollination occurs in maize when wind blows grains of pollen from the tassels to the silks that protrude from the tops of the ears.

[0005] The development of a hybrid maize variety in a maize seed production program may involve three steps: (1) the selection of plants from various germplasm pools for initial breeding crosses; (2) self-pollination of the selected plants from the breeding crosses for several generations to produce a series of inbred lines, which, individually breed true and are highly uniform; and (3) crossing a selected inbred line with an unrelated inbred line to produce the hybrid progeny. After a sufficient amount of inbreeding successive filial generations will merely serve to increase seed of the developed inbred.

[0006] During the maize inbreeding process, vigor of the line may decrease. Vigor may be restored when two different inbred lines are crossed to produce the hybrid progeny. An important consequence of the homozygosity and homogeneity of the inbred lines is that the hybrid between a defined pair of inbreds may be reproduced indefinitely as long as the homogeneity of the inbred parents is maintained. Once the inbreds that create a superior hybrid have been identified, a continual supply of the hybrid seed can be produced using these inbred parents and the hybrid corn plants can then be generated from this hybrid seed supply.

[0007] Pollen may be collected for several reasons, such as for testing, treatment, and pollination. However, gathering pollen from anthers of plants growing in the field subjects the harvesting operation to many variables, such as changes and inconsistencies in the weather, pests, interference from humans and other animals, and so on. Moreover, the maturation of the anthers may not be readily ascertainable or uniform across a large number of plants.

[0008] Accordingly, there is a need in the art for a method for growing anthers that allows high-quality pollen to be harvested in a controlled, efficient, reproducible, and less costly manner.

BRIEF SUMMARY OF VARIOUS EMBODIMENTS

[0009] The present invention addresses the above needs and achieves other advantages by providing an apparatus and method for the controlled growth and harvesting of pollen, such as pollen released from anthers of maize tassels. In general, the method includes separating a tassel from a maize plant prior to tassel maturation, continuing to grow the separated tassel in a growth chamber, and directing pollen from dehisced anthers of the separated tassel to a collection point, where the pollen is collected at the collection point for further processing.

[0010] Continuing to grow the separated tassel may comprise disposing the tassel in a liquid reservoir within the growth chamber. In some embodiments, an environmental condition within the growth chamber may be controlled. For example, the environmental condition may be temperature, humidity, lighting, and/or nutrient provision. Moreover, directing the pollen from the dehisced anthers may comprise vibrating the growth chamber. Alternatively or additionally, directing the pollen from the dehisced anthers may comprise directing air through the growth chamber, and, in some embodiments, directing the pollen from the dehisced anthers may further comprise vibrating the growth chamber as the air is directed through the growth chamber. In some cases, an inert material may be added to the air directed through the growth chamber to frictionally encourage dehiscence of undehisced anthers.

[0011] In still other embodiments, an apparatus for controlled harvesting of pollen may be provided that includes a growth chamber configured to receive a tassel separated from a maize plant prior to tassel maturation to allow continued growth of the separated tassel, and at least one outlet configured to direct pollen from dehisced anthers of the separated tassel to a collection point, where the pollen is collected at the collection point for further processing. The apparatus may include a liquid reservoir within the growth chamber that is configured to hold an amount of liquid, wherein the separated tassel is disposed in the liquid reservoir. The apparatus may further include at least one of a temperature regulating system or a humidity regulating system configured to control a respective one of a temperature or a humidity of the growth chamber. A light source may also be provided that is configured to provide light to the growth chamber, and the light source may include at least one of a fluorescent light, a halogen light, or an LED.

[0012] In some embodiments, the apparatus may include a nutrient source configured to provide at least one nutrient to the separated tassel within the growth chamber. Additionally or alternatively, the apparatus may include a vibration source configured to vibrate the growth chamber to encourage release of pollen from dehisced anthers. In some cases, the apparatus may include at least one inlet configured to direct air into the growth chamber, where the air directs the pollen from the dehisced anthers to the at least one outlet, and the apparatus may additionally include the vibration source configured to vibrate the growth chamber to encourage release of pollen from dehisced anthers. At least one inlet may be configured to direct an inert material with the air through the growth chamber to frictionally encourage dehiscence of undehisced anthers. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0014] FIG. 1 shows a schematic representation of a tassel in a liquid reservoir in accordance with an exemplary embodiment of the present invention;

[0015] FIG. 2 illustrates an apparatus for controlled harvesting of pollen in accordance with an exemplary embodiment of the present invention;

[0016] FIG. 3 illustrates an apparatus for controlled harvesting of pollen in accordance with another exemplary embodiment of the present invention;

[0017] FIG. 4 shows a schematic view of an apparatus for controlled harvesting of pollen in accordance with another exemplary embodiment of the present invention;

[0018] FIG. 5 illustrates a flowchart of a method of controlled harvesting of pollen in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

[0019] Some embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. Indeed, various embodiments of the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Some components of the apparatus for controlled harvesting of pollen and other related systems are not shown in one or more of the figures for clarity and to facilitate explanation of embodiments of the present invention.

[0020] With reference to Fig. 1, a tassel 10 of a maize plant is shown. The tassel 10 is the male part of the maize plant that includes anthers 15 that release pollen when the tassels and their anthers are mature. The pollen that is released can self-pollinate or pollinate other maize plants via the silk or style of the maize ears (not shown), which form the female part of the plants. Each pollinated silk becomes an individual kernel of maize that may grow to contain an ovule that can be used to reproduce the maize plant itself. [0021] Agricultural companies are often interested in harvesting pollen from plants, such as maize plants, for various purposes, such as for the pollination of maize plants in a planned manner. In the field, maize plants grow at various rates, depending on the environmental conditions, the particular plant, and other factors. For example, a maize plant growing in a hot and humid climate may not exhibit the same rate of growth and maturation of the tassels bearing pollen-releasing anthers as the same maize plant growing in a cooler and less humid environment. Thus it may be difficult to accurately gauge the appropriate time to collect pollen from maize plants to ensure that high-quality pollen (e.g., pollen that is "ready" to pollinate another maize plant) is harvested, and the timing may be different even as between two different plants growing in the same field.

[0022] Moreover, the collection process itself may be tedious and time

consuming. For example, conventional methods of harvesting pollen from maize plants involve using tassel bags in the field or greenhouse where the plants are growing and waiting up to 24 hours to allow the pollen to shed and drop into the tassel bags. In this time, not all the pollen may be shed from the tassel about which the tassel bag is disposed, and thus some of the pollen may be left behind on the maize plant in the process of collecting the already shed pollen. The harvesting of pollen in such a manner may, in some cases, also inadvertently collect other environmental debris, such as dust, bugs, non-pollen plant particles, and so on.

[0023] Accordingly, embodiments of a method and apparatus are provided for facilitating the controlled growth and harvesting of pollen. The inventors have discovered that tassels cut from maize plants and placed in growth chambers in accordance with the embodiments described below allow the tassels to continue to develop at a controlled rate. Thus, once the anthers on the tassel begin to release pollen, the growth chamber may be used to encourage further release and collection of pollen on demand.

[0024] Turning now to Fig. 2, an apparatus 100 for controlled harvesting of pollen is shown. The apparatus 100 may include a growth chamber 110 configured to receive a tassel (such as the tassel 10 of Fig. 1) therein. The growth chamber 110 may have a tubular configuration in some embodiments (as shown) and may be made of a plastic material, such as polyvinyl chloride (PVC). In this regard, the tassel may be separated from a maize plant (e.g., cut from the maize plant) prior to tassel maturation and placed in the growth chamber 110, where it continues to grow in a controlled manner, as described in greater detail below. The apparatus 100 may further include at least one outlet 120 defined by the growth chamber 110. The outlet 120 may be configured to direct pollen from dehisced anthers of the separated tassel to a collection point. In the embodiment of Fig. 2, for example, the collection point is a collection tube 130 (e.g., a 50 ml collection tube), as shown. In some embodiments, the pollen may be collected at the collection point 130 for further processing, such as for pollination of maize plants.

[0025] The apparatus 100 may, in some embodiments, include a sealable lid 140 that is configured to engage and disengage the growth chamber 110. For example, the sealable lid 140 may include internal threads (not shown) that are configured to mate with corresponding external threads (not shown) of the growth chamber 110, such that a user may open or close the growth chamber. In this way, the growth chamber 110 may be opened (e.g., by unscrewing the sealable lid 140) to allow a cut tassel to be placed within the growth chamber and may then be closed (e.g., by screwing on the sealable lid 140) to allow the tassel within to grow in an undisturbed and controlled manner. The sealable lid 140 may, for example, include knurls 145 or other features on its exterior surface to facilitate a user' s grip and handling of the lid to open and close the growth chamber 110. At the same time, the lid 140 may be configured such that, when closed, the interior of the growth chamber 110 is sufficiently isolated from the external environment so as to prevent external debris and other external environmental conditions from entering into and affecting the growth of the tassel within the growth chamber, as well as preventing the pollen released within the growth chamber from escaping to the external environment.

[0026] In some cases, the apparatus 100 may also include a liquid reservoir 150 (shown in Fig. 1) within the growth chamber 110 that is configured to hold an amount of liquid, where the separated tassel 10 is disposed in the liquid reservoir, as shown in Fig. 1. The liquid reservoir 150 may, for example, be configured to hold a liquid 152 such as water, a glucose- water solution, or other solutions so as to provide hydration and, in some cases, nutrients to the separated tassel 10. The liquid reservoir 150 may, for example, be made out of a material such as plastic or glass and may include an opening 155 through which the tassel peduncle 20 is received. In this regard, the opening 155 may include one or more flaps 160 or membranes configured to allow the tassel peduncle 20 to be received within the reservoir 150, but at the same time maintain the liquid within the reservoir (e.g., to reduce spillage of the liquid). Moreover, in some embodiments, the liquid reservoir 150 may include a port 165 configured to allow additional liquid 152 (e.g., the water and/or nutrient solution) to be passed into the liquid reservoir, such as to re-fill the liquid reservoir as the tassel 10 consumes the liquid. Thus, the port 165 may be connected (e.g., via tubing 170) to a nutrient source that is configured to provide at least one nutrient to the separated tassel within the growth chamber via the liquid 152 in the liquid reservoir 150.

[0027] Referring again to Fig. 2, the pollen from dehisced anthers of the separated tassel may be directed to the collection point 130 in various ways. In one

embodiment, for example, the growth chamber 110 may be vibrated (e.g., via a vibration source that is connected to the growth chamber), and the vibrations may shake the pollen out of the anthers and allow them to fall (e.g., under the influence of the force of gravity) toward the outlet 120 and into the collection point 130.

[0028] In other embodiments, the apparatus 100 may be configured such that pollen is directed from the dehisced anthers by directing air through the growth chamber, such as depicted in Fig. 3. In Fig. 3, the apparatus 100 includes a growth chamber 110 with an outlet 120 disposed in an upper location on the growth chamber, rather than at the bottom as shown in Fig. 2. In addition, the apparatus 100 may include at least one inlet 180 that is configured to direct air into the growth chamber 110, wherein the air directs the pollen from the dehisced anthers to the at least one outlet 120. The air flow via the one or more inlets 180 may be minimal, such that a positive pressure may be established within the growth chamber 110 as compared to the outside environment. In other cases, however, air at greater flow rates may be introduced within the growth chamber 110, such that pollen released from the anthers is pushed (via the flowing air) to the outlet 120 and the collection point. In this regard, air flow through the growth chamber 110 may be established by generating an air pressure at the inlets 180 that is greater than the pressure at the outlet 120 and/or the collection point (e.g., "pushing" air through the growth chamber), or, conversely, by generating an air pressure at the outlet 120 that is lower than the pressure at the inlets 180 (e.g., via "suction" at the outlet).

[0029] Moreover, the flow of air through the growth chamber 110 via the inlet 180 may be combined with vibration of the growth chamber (e.g., provided by the vibration source) to further encourage released (or almost released) pollen to be shed from the anthers and directed to the outlet 120 and, ultimately, to the collection point. As shown in Fig. 3, for example, the growth chamber 110 may be disposed on a vibration stand 190 that is configured to hold the growth chamber and transmit vibrations to the growth chamber.

[0030] For example, in cases where at least some of the tassels that are placed in growth chambers (such as the growth chambers 110 shown in Figs. 2 and 3) are characterized as poor pollen shedders, physical forces may be used to cause collisions of the anthers on the tassel with one another so as to encourage the release of pollen. The physical forces may be provided through vibration of the growth chamber 110, as described above. In other cases, however, at least one of the one or more inlets 180 may be configured to direct an inert material with the air through the growth chamber 110 to frictionally encourage dehiscence of undehisced anthers. Such inert materials may include, for example, ball bearings, frictional garnet, and other substances that can abrade and/or fracture undehisced anthers through collision with the anthers and cause pollen to be released. In such embodiments, the released pollen may be collected via a filter, such as a mesh disposed at the outlet 120, through which only pollen may pass. In this way, debris (e.g., pieces of abraded anther and the inert materials themselves) may remain within the growth chamber while the released pollen may be harvested at the collection point. In the embodiment of Fig. 2, for example, the filter 195 may be disposed at the bottom of the growth chamber 110, whereas in the embodiment of Fig. 3, the filter 195 may be disposed in or near the connection of the outlet 120 to the growth chamber 110.

[0031] In still other embodiments, the apparatus 100 may configured such that at least one environmental condition within the growth chamber is controlled, such as temperature, humidity, lighting, or nutrient provision. Turning to Fig. 4, for example, the growth chamber 110 may be connected to at least one of a temperature regulating system 200 or a humidity regulating system 210 configured to control a respective one of a temperature or a humidity of the growth chamber. The temperature regulating system 200 may, for example, include a heater, a thermostat, a cooler, a fan, and/or a controller (e.g., circuitry for controlling and coordinating the actuation of these elements) and may be in fluid communication with the interior of the growth chamber 110 (e.g., via one or more of the inlets 180) to regulate the temperature of the interior for the tassel disposed therein. Similarly, the humidity regulating system 210 may include a heater, a vapor source, a cooler, a fan and/or a controller (e.g., circuitry for controlling and coordinating the actuation of these elements) and may be in fluid communication with the interior of the growth chamber 110 (e.g., via one or more of the inlets 180) to regulate the humidity of the interior for the tassel disposed therein. Moreover, one or more sensors (not shown) may be provided within the growth chamber 110 to detect the temperature and/or humidity of the interior of the growth chamber and may be configured to relay the temperature and/or humidity readings to the respective controllers, which in turn may be configured to actuate the appropriate system components to adjust the temperature and/or humidity

accordingly.

[0032] In still other embodiments, the apparatus 100 may further comprise a light source 220 configured to provide light to the interior of the growth chamber 110. The light source 220 may include at least one of a fluorescent light, a halogen light, or a light emitting diode (LED), or a combination thereof. The light source 220 may, for example, simulate light from the sun, thereby encouraging growth and maturation of the tassel. Moreover, as described above, the apparatus 100 may further comprise a nutrient source 230 configured to provide at least one nutrient to the separated tassel within the growth chamber 110, such as via an inlet 180 (shown in Fig. 3) to the growth chamber and/or the port 165 of the liquid reservoir 150 (shown in Fig. 1).

[0033] Turning now to Fig. 5, embodiments of a method for controlled harvesting of pollen as described above is shown. The method may include separating a tassel from a maize plant prior to tassel maturation at Block 250 and continuing to grow the separated tassel in a growth chamber at Block 260. Pollen from dehisced anthers of the separated tassel may be directed to a collection point at Block 270. In some cases, continuing to grow the separated tassel may comprise disposing the tassel in a liquid reservoir within the growth chamber at Block 280.

[0034] In some embodiments, the environmental condition within the growth chamber may be controlled at Block 290. Such environmental conditions may include temperature, humidity, lighting, or nutrient provision.

[0035] Pollen may be directed from the dehisced anthers by vibrating the growth chamber in some cases. In other cases, pollen may be directed from the dehisced anthers by directing air through the growth chamber. In still other cases, the pollen from the dehisced anthers may be directed by vibrating the growth chamber as the air is directed through the growth chamber. Furthermore, an inert material may be added to the air directed through the growth chamber to frictionally encourage dehiscence of undehisced anthers. [0036] Exemplary embodiments of the present invention have been described above with reference to block diagrams and flowchart illustrations of methods and apparatuses (e.g., systems), such as those shown in Figs. 4 and 5. In some

embodiments, certain ones of the operations shown in Fig. 5 above may be modified or further amplified as described above. Furthermore, in some embodiments, additional optional operations may be included, some examples of which are shown in dashed lines in Fig. 5. Modifications, additions, or amplifications to the operations above may be performed in any order and in any combination.

[0037] Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. For example, although the example of a maize plant is described above, embodiments of the invention may be applicable to other types of plants for controlled growth and harvesting of their respective pollen grains. In addition, although some components of the apparatus and systems described above are depicted in Figs. 1-4, other components that were not shown in the drawings for sake of clarity may be used in conjunction with the described components. Moreover, systems in communication with the growth chamber shown in Fig. 4, for example, although shown as being separate and distinct from each other, may, in some cases, be embodied by the same system or may share components with other systems that are also in communication with the growth chamber. Furthermore, in some cases, such systems may be external to the growth chamber, whereas in other cases the systems may at least partially be embodied by the growth chamber, for example, being located at least partially within the interior of the growth chamber.

[0038] Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

WHAT IS CLAIMED IS:

1. A method for controlled harvesting of pollen comprising:

separating a tassel from a maize plant prior to tassel maturation;

continuing to grow the separated tassel in a growth chamber; and

directing pollen from dehisced anthers of the separated tassel to a collection point,

wherein the pollen is collected at the collection point for further processing.

2. The method of Claim 1, wherein continuing to grow the separated tassel comprises disposing the tassel in a liquid reservoir within the growth chamber.

3. The method of Claim 1 further comprising controlling an

environmental condition within the growth chamber.

4. The method of Claim 3, wherein the environmental condition is one of temperature, humidity, lighting, or nutrient provision.

5. The method of Claim 1, wherein directing the pollen from the dehisced anthers comprises vibrating the growth chamber.

6. The method of Claim 1, wherein directing the pollen from the dehisced anthers comprises directing air through the growth chamber.

7. The method of Claim 6, wherein directing the pollen from the dehisced anthers further comprises vibrating the growth chamber as the air is directed through the growth chamber.

8. The method of Claim 6 further comprising adding an inert material to the air directed through the growth chamber to frictionally encourage dehiscence of undehisced anthers.

9. An apparatus for controlled harvesting of pollen comprising: a growth chamber configured to receive a tassel separated from a maize plant prior to tassel maturation to allow continued growth of the separated tassel; and

at least one outlet configured to direct pollen from dehisced anthers of the separated tassel to a collection point,

wherein the pollen is collected at the collection point for further processing.

10. The apparatus of Claim 9 further comprising a liquid reservoir within the growth chamber configured to hold an amount of liquid, wherein the separated tassel is disposed in the liquid reservoir.

11. The apparatus of Claim 9 further comprising at least one of a temperature regulating system or a humidity regulating system configured to control a respective one of a temperature or a humidity of the growth chamber.

12. The apparatus of Claim 9 further comprising a light source configured to provide light to the growth chamber.

13. The apparatus of Claim 12, wherein the light source comprises at least one of a fluorescent light, a halogen light, or an LED.

14. The apparatus of Claim 9 further comprising a nutrient source configured to provide at least one nutrient to the separated tassel within the growth chamber.

15. The apparatus of Claim 9 further comprising a vibration source configured to vibrate the growth chamber to encourage release of pollen from dehisced anthers.

16. The apparatus of Claim 9 further comprising at least one inlet configured to direct air into the growth chamber, wherein the air directs the pollen from the dehisced anthers to the at least one outlet.

17. The apparatus of Claim 16 further comprising a vibration source configured to vibrate the growth chamber to encourage release of pollen from dehisced anthers.

18. The apparatus of Claim 16, wherein the at least one inlet is configured to direct an inert material with the air through the growth chamber to frictionally encourage dehiscence of undehisced anthers.