US 5,763,755 AGrant
Inbred Corn Line ZSO1172
Issue Date:1998-06-09
•11 Claims
Abstract
Broadly this invention provides inbred corn line ZSO1172. The methods for producing a corn plant by crossing the inbred line ZSO1172 are encompassed by the invention. Additionally, the invention relates to the various parts of inbred ZSO1172 including culturable cells. This invention relates to hybrid corn seeds and plants produced by crossing the inbred line ZSO1172 with at least one other corn line.
Metadata
Assignee
- Garst Seed Company
Inventor
- Mario Carlone
Application Information
Application Number:US 6268005
Filing Date:1996-04-03
Priority Date:1996-04-03
Art Unit:183
Classifications
IPC:
A01H 500A01H 400A01H 100C12N 504
Field of Search:
80047435200;205;250;DIG. 5658;DIG. 7172.3;172.1;240.4;240.45;240.47;240.49;240.5;412;424;430;430.1
Patent Drawings
This patent does not have any drawings.
Description
Field of the Invention
This invention is in the field of corn breeding, specifically relating to an inbred corn line designated ZSO1172.
Background of the Invention
The original maize plant was indigenous to the Western Hemisphere. The plants were weedlike and only through the efforts of early breeders was a cultivated crop species developed. The physical traits of maize are such that self pollination or cross pollination can occur. Each plant has a separate male and female flower, the tassel and ear, respectively. Natural pollination occurs when wind transfers pollen from tassel to the silks on the corn ears. This type of pollination contributed to the wide variation of maize varieties present in the Western Hemisphere.
The development of a planned breeding program for maize only occurred in the last century. Originally, maize was an open pollinated variety having heterogeneous genotypes. The maize farmer selected uniform ears from the yield of these genotypes and reserved them for planting the next season. The result was a field of maize plants that were segregating for a variety of traits. This type of maize selection lead to at most incremental increases in seed yield.
Large increases in seed yield were the result of the development of hybrid corn varieties in planned breeding programs. Hybrids were developed by selecting corn lines and selfing these lines for several generations to develop homozygous pure inbred lines and crossing selected inbred lines with unrelated inbred lines to produce hybrid progeny (F1). Inbred lines can be difficult to produce since the inbreeding process in corn decreases the vigor. However, when two inbred lines are crossed, the hybrid plant evidences greatly increased vigor compared to open pollinated segregating maize plants. An important factor of the homozygosity and the homogeneity of the inbred lines is that the hybrid from any cross will always be the same, and can be reproduced.
The ultimate objective of the commercial maize seed companies is to produce high yielding, agronomically sound plants which perform well in certain regions or areas of the Corn Belt. To produce these types of hybrids, the companies must develop inbreds which carry needed traits into the hybrid combination. Hybrids are not uniformly adapted for the Corn Belt, but are specifically adapted for regions of the Corn Belt. Northern regions of the Corn Belt require shorter season hybrids than do southern regions of the Corn Belt. Hybrids that grow well in Colorado and Nebraska soils may not flourish in rich Illinois soil. Thus, a variety of major agronomic traits are important in hybrid combination for the various Corn Belt regions, and have an impact on hybrid performance.
Inbred line development and hybrid testing have been emphasized in the past half century in commercial maize production as a means to increase hybrid performance. Inbred development is usually done by pedigree selection. Pedigree selection can be selection in an F.sub.2 population produced from a planned cross of two genotypes (often elite inbred lines), or selection of progeny of synthetic varieties, open pollinated, composite, or backcross populations. This type of selection is effective for highly inheritable traits, but other traits, for example, yield requires replicated test crosses at a variety of stages for accurate selection.
Maize breeders select for a variety of traits in inbreds that impact hybrid performance along with selecting for acceptable parental traits. Such traits include yield potential in hybrid combination; dry down; maturity; grain moisture at harvest; greensnap; resistance to root lodging; resistance to stalk lodging; grain quality; disease and insect resistance; ear and plant height; performance in different soil types such as: low level of organic matter, clay, sand, black, high pH, low pH; performance in: wet environments, drought environments, and no tillage conditions. These traits appear to be governed by a complex genetic system that makes selection and breeding of an inbred line extremely difficult. Even if an inbred in hybrid combination has excellent yield (a desired characteristic), it may not be useful because it fails to have acceptable parental traits such as seed yield, seed size, pollen production, good silks, plant height, etc.
To illustrate the difficulty of breeding and developing inbred lines, the following example is given. Two inbreds compared for similarity of 29 traits differed significantly for 18 traits between the two lines. If 18 simply inherited single gene traits were polymorphic with gene frequencies of 0.5 in the parental lines, and assuming independent segregation (as would essentially be the case if each trait resided on a different chromosome arm), then the specific combination of these traits as embodied in an inbred would only be expected to become fixed at a rate of one in 262,144 possible homozygous genetic combinations. Selection of the specific inbred combination is also influenced by the specific selection environment on many of these 18 traits which makes the probability of obtaining this one inbred even more remote. Thus, the general procedure of producing a non segregating F.sub.1 generation and self pollinating to produce a F.sub.2 generation that segregates for traits does not easily lead to a useful inbred. Great care and breeder expertise must be used in selection of breeding material to continue to increase yield and agronomics of inbreds and resultant commercial hybrids.
Summary of the Invention
The present invention relates to an inbred corn line ZSO1172. Specifically, this invention relates to plants and seeds of this line. Additionally, this relates to a method of producing hybrid seed corn from this inbred. More particularly, this invention relates to the unique combination of traits that combine in corn line ZSO1172.
Generally then, broadly the present invention includes an inbred corn seed designated ZSO1172. This seed produces a corn plant.
The invention also includes the tissue culture of regenerable cells of ZSO1172 wherein the tissue regenerates plants having the genotype of ZSO1172. The tissue culture is selected from the group consisting of leaves, pollen, embryos, roots, root tips, anthers, silk, flowers, kernels, ears, cobs, husks and stalks, and cells and protoplasts thereof. The corn plant regenerated from ZSO1172 having ZSO1172's genotype.
The invention extends to hybrid seed produced by planting, in pollinating proximity, seeds of corn inbred lines ZSO1172 and another inbred line; cultivating corn plants resulting from said planting; preventing pollen production by the plants of one of the inbred lines; allowing natural cross pollinating to occur between said inbred lines; and harvesting seeds produced on plants of the inbred. The hybrid seed produced by hybrid combination of plants of inbred corn seed designated ZSO1172 and plants of another inbred line. Hybrid plants grown from this hybrid seed.
The invention further includes a method of hybrid F1 production. A first generation (F1) hybrid corn plant produced by the process of planting, in pollinating proximity, seeds of corn inbred lines ZSO1172 and another inbred line; cultivating corn plants resulting from said planting; preventing pollen production by the plants of one of the inbred lines; allowing natural cross pollinating to occur between said inbred lines; harvesting seeds produced on plants of the inbred; and growing a harvested seed.
A tissue culture of the regenerable cells of hybrid plants produced with use of ZSO1172 genetic material. A tissue culture of the regenerable cells of the corn plant produced by the method described above.
Definitions
In the description and examples which follow, a number of terms are used. In order to provide a clear and consistent understanding of the specifications and claims, including the scope to be given such terms, the following definitions are provided.
BL MOIST
The moisture percentage of the grain at black layer, i.e., when 50% of the plants per plot have reached physiological maturity.
COLD GERM
Cold Germ is a measurement of seed germination under cold soil conditions. Data is reported as percent of seed germinating.
ECB
European corn borer a maize eating insect. ECBI is the first brood generation of European corn borers. ECBII is the second generation of European corn borers.
EMERGE
The number of emerged plants per plot (planted at the same seedling rate) collected when plants have two fully developed leaves.
GI
This is a selection index which provides a single quantitative measure of the worth of a hybrid based on four traits. Yield is the primary trait contributing to index values. The GI value is calculated by combining stalk lodging, root lodging, yield and dropped ears according to the attached mathematical formula:
GLS
Gray Leaf Spot (Cercospora Zeae) disease rating. This is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*
GW
Goss' Wilt (Corynebacterium nebraskense). This is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*
HEATP10
The number of Growing Degree Units (GDU's) or heat units required for an inbred line or hybrid to have approximately 10 percent of the plants shedding pollen. This trait is measured from the time of planting. Growing Degree Units are calculated by the Barger Method where the GDU's for a 24 hour period are: ##EQU1##
The highest maximum temperature used is 86.degree. F. and the lowest minimum temperature used is 50.degree. F. For each inbred or hybrid it takes a certain number of GDU's to reach various stages of plant development.
HEATBL
The number of GDU's after planting when approximately 50 percent of the inbred or hybrid plants in a plot have grain which has reached physiological maturity (black layer).
HEATPEEK
The number of GDU's after planting of an inbred when approximately 50 percent of the plants show visible tassel extension.
HEATP50 or HTP50
The number of GDU's required for an inbred or hybrid to have approximately 50 percent of the plants shedding pollen. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.
HEATP90
The number of GDU's accumulated from planting when the last 100 percent of plants in an inbred or hybrid are still shedding enough viable pollen for pollination to occur. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.
HEATS10
The number of GDU's required for an inbred or hybrid to have approximately 10 percent of the plants with silk emergence of at least 0.5 inches. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.
HEATS50 or HTS50
The number of GDU's required for an inbred or hybrid to have approximately 50 percent of the plants with silk emergence of at least 0.5 inches. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.
HEATS90
The number of GDU's required for an inbred or hybrid to have approximately 90 percent of the plants with silk emergence of at least 0.5 inches. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.
MDMV.sub.A
Maize Dwarf Mosaic Virus strain A. The corn is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*
MDMV.sub.B
Maize Dwarf Mosaic Virus strain B. This is rated on a 1-9 scale with a "1" being very susceptible and a "9" being very resistant.*
MOISTURE
The average percentage grain moisture of an inbred or hybrid at harvest time.
NLB
Northern Leaf Blight (Exserohilum turcicum) disease rating. This is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*
PCT TILLER
The total number of tillers per plot divided by the total number of plants per plot.
PLANT
This term includes plant cells, plant protoplasts, plant cell tissue cultures from which corn plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants or parts of plants, such as embryos, pollen, flowers, kernels, ears, cobs, leaves, husks, stalks, roots, root tips, anthers, silk and the like.
PLANT HEIGHT
The distance in centimeters from ground level to the base of the tassel peduncle.
RM
Predicted relative maturity based on the moisture percentage of the grain at harvest. This rating is based on known set of checks and utilizes standard linear regression analyses and is referred to as the Minnesota Relative Maturity Rating System.
SHED
The volume of pollen shed by the male flower rated on a 1-9 scale where a "1" is a very light pollen shedder, a "4.5" is a moderate shedder, and a "9" is a very heavy shedder. If the Table(s) 3 have reduced the 1-9 shed scale to a 1-3 shed scale then any shed on Table 3 can be multiplied by 3 to reach the 1-9 shed scale.
SLB
Southern Leaf Blight (Bipolaris maydis) disease rating. This is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*
TWT
The measure of the weight of grain in pounds for a one bushel volume adjusted for percent grain moisture.
VIGOR
Visual rating of 1 to 9 made 2-3 weeks post-emergence where a "1" indicates very poor early plant development, and a "9" indicates superior plant development.
WARM GERM
A measurement of seed germination under ideal (warm, moist) conditions. Data is reported as percent of seeds germinating.
YIELD (YLD)
Actual yield of grain at harvest adjusted to 15.5% moisture. Measurements are reported in bushels per acre.
% DROPPED EARS (DE)
The number of plants per plot which dropped their primary ear divided by the total number of plants per plot.
% LRG FLAT
Percentage by weight of shelled corn that passes through a 26/64 inch round screen and a 14/64 inch slot screen, but does not pass through a screen with 20.5/64 inch round openings.
% LRG ROUND
Percentage by weight of shelled corn that passes through a 26/64 inch round screen, but does not pass through a 14/64 inch slot screen or a screen with 20.5/64 inch round openings.
% MED FLAT
Percentage by weight of shelled corn that passes through a 20.5/64 inch round screen and a 13/64 inch slotted screen, but does not pass through a screen with 17/64 inch round openings.
% MED ROUND
Percentage by weight of shelled corn that passes through a 20.5/64 inch round screen, but does not pass through a 13/64 inch slot screen or a screen with 17/64 inch round openings.
%SML FLAT
Percentage by weight of shelled corn that passes through a 17/64 inch round screen and a 12/64 inch slotted screen, but does not pass through a screen with 15/64 inch round openings.
% SML ROUND
Percentage by weight of shelled corn that passes through a 17/64 inch round screen, but does not pass through a 12/64 inch slotted screen or a screen with 15/64 inch round openings.
% ROOT LODGE (RL)
Percentage of plants per plot leaning more that 30 degrees from vertical divided by total plants per plot.
% STALK LODGE (SL)
Percentage of plants per plot with the stalk broken below the primary ear node divided by the total plants per plot.
* Resistant--on a scale of 1-9 with 9 evidencing the trait most strongly: 1-2.9 ratings are susceptible, 3-5.9 ratings are intermediate, and 6-9 ratings are resistant.
Detailed Description of the Invention
ZSO1172 can be used as a male line due to its pollen shed and seed production abilities. This ZSO1172 line evidences good specific combining ability with certain stiff stalk females.
The inbred has shown uniformity and stability within the limits of environmental influence for all the traits as described in the Variety Description Information (Table 1) that follows. Most of the data in the Variety Description information was collected at Slater, Iowa.
The inbred has been self-pollinated for a sufficient number of generations to give inbred uniformity. During plant selection in each generation, the uniformity of plant type was selected to ensure homozygosity and phenotypic stability. The line has been increased in isolated farmland environments with data on uniformity and agronomic traits being observed to assure uniformity and stability. No variant traits have been observed or are expected in ZSO1172.
The best method of producing the invention, ZSO1172 which is substantially homozygous, is by planting the seed of ZSO1172 which is substantially homozygous and self-pollinating or sib pollinating the resultant plant in an isolated environment, and harvesting the resultant seed or the resultant pollen.
The Munsell code is a reference book of color which is known and used in the industry and by persons with ordinary skill in the art of plant breeding.
The purity and homozygosity of inbred ZSO1172 is constantly being tracked using isozyme genotypes as shown in Table 2.
Isozyme Genotypes for ZSO1172
Isozyme data were generated for inbred corn line ZSO1172 according to procedures known and published in the art. The data in Table 2 gives the electrophoresis data on ZSO1172.
Inbred and Hybrid Performance of ZSO1172
The traits and characteristics of inbred corn line ZSO1172 are listed to compare with other inbreds and/or in hybrid combination. ZSO1172 data shows the characteristics and traits of importance, giving a snapshot of ZSO1172.
Table 3A shows a comparison between ZSO1172 and PVP#8500037 . ZSO1172 has significantly greater plant and ear height, less seedling emergence but greater vigor than PVP#8500037 . It is later flowering, as evidenced by the greater number of GDU's to HEATP and HEATS ratings, but dries down faster than PVP#8500037 as evidenced by the lower grain moisture at harvest. Seed size of ZSO1172 is generally larger and it produces significantly more percent large round, large flat and medium round kernels.
Table 3B compares ZSO1172 with PVP#9200249. ZSO1172 is significantly taller than PVP#9200249 but has comparable ear height. Seedling vigor is significantly greater and pollen shed is less. ZSO1172 is a later maturity line as denoted by the greater GDU's to HEATPEEK, HEATP, HEATS, HEATBL and grain moisture at harvest. Warm and cold germination are significantly better than PVP#9200249. There are significantly less large kernel sizes for ZSO1172 and more medium and small sizes.
Table 3C is an inbred comparison between ZSO1172 and ZSO1101. ZSO1172 has significantly lower plant and ear height and less seedling emergence with less pollen shed. ZSO1172 has earlier tassel emergence, earlier pollen shed and similar silk dates as ZSO1101. ZSO1172 produces more large round, large flat and medium round kernel sizes than ZSO1101.
Table 4 shows the GCA (general combining ability) estimates of ZSO1172 compared with the GCA estimates of the other inbreds. The estimates show the general combining ability is weighted by the number of experimentlocation combinations in which the specific hybrid combination occurs. The interpretation of the data for all traits is that a positive comparison is a practical advantage. A negative comparison is a practical disadvantage. The general combining ability of an inbred is clearly evidenced by the results of the general combining ability estimates. This data compares the inbred parent in a number of hybrid combinations to a group of "checks". The check data is from other companies' hybrids, particularly the leader in the industry and ICI Seeds' commercial products and pre-commercial hybrids which were grown in the same sets and locations.
Table 4A shows ZSO1172 crossed in 514 hybrid combinations. ZSO1172 shows a positive advantage for moisture, stalk and root lodging, dropped ears and test weight.
Table 4B compares ZSO1172 in random hybrid combinations with PVP#850007, PVP#9200249, and ZSO1101 in random combinations. Although ZSO1172 shows less yield advantage, it shows a strong moisture advantage over all three inbreds. Stalks and roots are comparable, but ZSO1172 shows less of a tendency to drop ears and has better advantage for test weight.
Table 5A shows the advantage the ZSO1172 hybrid has over two commercially available ICI Seeds' hybrids. Compared to 8550, the ZSO1172 hybrid is later maturing but has comparable yield, slightly better stalks, slightly poorer roots, and much improved test weight. Compared to 8539IT, which is of the same maturity, the ZSO1172 hybrid has the advantage in yield, stalk and root lodging, and test weight.
Table 6A shows the entomology strengths and weaknesses of the inbred.
The inbred ZSO1172 can be employed as the male plant in a hybrid production field. This inbred is a medium height line with moderate ear height.
The foregoing is set forth by way of example and is not intended to limit the scope of the invention.
This invention also is directed to methods for producing a corn plant by crossing a first parent corn plant with a second parent corn plant wherein the first or second parent corn plant is an inbred corn plant from the line ZSO1172. Further, both first and second parent corn plants can come from the inbred corn line ZSO1172. A variety of breeding methods can be selected depending on the mode of reproduction, the trait, the condition of the germplasm. Thus, any such methods using the inbred corn line ZSO1172 are part of this invention: selfing, backcrosses, hybrid production, crosses to populations, haploid and anther culturing and the like.
Various culturing techniques known to those skilled in the art, such as haploid, transformation, and a host of other conventional and unconventional methods are within the scope of the invention. All plants and plant cells produced using inbred corn line ZSO1172 are within the scope of this invention. The invention encompasses the inbred corn line used in crosses with other, different, corn inbreds to produce (F1) corn hybrid seeds and plants with the characteristics that make good hybrids. This invention includes cells which upon growth and differentiation produce corn plants having the physiological and morphological characteristics of the inbred line ZSO1172.
Duncan, from at least 1985-1988 produced literature on plant regeneration from callus. Both inbred and hybrid callus have resulted in regenerated plants at excellent efficiency rates. Somatic embryogenesis has been performed on various maize tissue such as glume which before the 1980's was considered unusable for this purpose. The prior art clearly teaches the regeneration of plants from various maize tissues.
European Patent Application, publication 160,390, describes tissue culture of corn which can be used by those skilled in the art. Corn tissue culture procedures are also described in the literature as early as 1982.
A deposit of at least 2500 seeds of the inbred seed of this invention is maintained by ICI Seeds, 2369 330th Street, Slater, Iowa 50244. Access to this deposit will be available during the pendency of this application to the Commissioner of Patents and Trademarks and persons determined by the Commissioner to be entitled thereto upon request. The Applicant made a deposit on Jun. 11, 1997, of at least 2500 seeds of inbred corn Line ZS01172 with the American Type Culture Collection (ATCC), located at 12301 Parklawn Drive, Rockville, Md. 20852. The ATCC accession number is 209106. Additionally the Applicant has satisfied all of the requirements of C.F.R. .sctn.1.801-809, including providing an indication of the viability of the sample. The ATCC deposit will be maintained in that depository, which is a public depository, for a period of 30 years, or 5 years after the last request, or for the effective life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period.
Inbreds designated MBS are available from Mike Brayton Seed in Iowa. Inbreds designated SGI are available from Seed Genetic Inc. in New Jersey. Information on some ZS designations may be available from the PVP office.
Accordingly, the present invention has been described with some degree of particularity directed to the preferred embodiment of the present invention. It should be appreciated, though, that the present invention is defined by the following claims construed in light of the prior art so that modifications or changes may be made to the preferred embodiment of the present invention without departing from the inventive concepts contained herein.
Claims
We claim:
1. Inbred corn seed designated ZSO1172, some of said seed deposited in the ATCC and carry accession number 209106.
2. A corn plant produced by the seed of claim 1.
3. A tissue culture of regenerable cells of ZSO1172 of claim 1 wherein the cells of the tissue culture regenerates plants comprising the genetype phenotype of ZSO1172.
4. A tissue culture according to claim 3, the tissue culture selected from the group consisting of leaves, pollen, embryos, roots, root tips, anthers, silk, flowers, kernels, ears, cobs, husks and stalks, and cells and protoplasts thereof.
5. A corn plant comprising the phenotype of ZSO1172 regenerated from the cells of the tissue culture of claim 3.
6. Hybrid seed produced by: (a) planting, in pollinating proximity, seeds according to claim 1 of corn inbred lines ZSO1172 and another inbred line, one of said inbred lines not releasing pollen; (b) cultivating corn plants resulting from said planting; (c) allowing natural cross pollinating to occur between said inbred lines; and (d) harvesting seeds produced on the non pollen releasing inbred.
7. Hybrid seed produced by hybrid combination of plants of inbred corn seed designated ZSO1172 in claim 1 and plants of another inbred line.
8. Hybrid plants grown from seed of claim 7.
9. A first generation (F1) hybrid corn plant produced by using ZSO1172 according to claim 1 the process of: (a) planting, in pollinating proximity, seeds of corn inbred lines ZSO1172 and another inbred line; (b) cultivating corn plants resulting from said planting; (c) preventing pollen production by the plants of one of the inbred lines; (d) allowing natural cross pollinating to occur between said inbred lines; (e) harvesting seeds produced on plants of the inbred line of step (c); and (f) growing a harvested seed of step (e).
10. A tissue culture of the regenerable cells of the corn plant of claim 8.
11. A tissue culture of the regenerable cells of the corn plant of claim 9.
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