A new and distinct corn plant, which is the product of a cross between gamagrass, Tripsacum laxum, and diploid perennial teosinte, Zea diploperennis. This plant is fertile, has proven to be cross compatible with Zea mays L. and offers an avenue to expand the gene pool for commercial corn varieties. The instant plant is perennial with well developed rhizomes, aerenchyma tissue in its roots, abundant seed and prolific vegetation production, traits that give it improved value as a forage crop.

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Patent
   PP17444
Priority
Mar 14 2005
Filed
Mar 14 2005
Issued
Feb 27 2007
Expiry
Apr 18 2025
Extension
35 days
Inventors
Eubanks, M…
Assg.orig
Assg.curr
Entity
unknown
Referenced by
0
References
2
Maint.:
n/a
BACKGROUND OF THE NE…
DESCRIPTION OF ILLUS…
COMPARISON TO ȁ…
1. A new and distinct variety of corn plant, substantially as herein shown and described, that is characterized by its profuse production of fruit, perennial habit, vigorous vegetative production of culms, roots with aerenchyma, asexual reproduction by rhizomes, stem cuttings, and anther culture, and its good combining ability with corn that permits movement of new genes and agronomic traits into corn using conventional plant breeding methods.

Botanical classification: Zea diploperennis×Tripsacum laxum.

Cultivar name: ‘Venus Express’.

BACKGROUND OF THE NEW PLANT

Two wild grasses, diploid perennial teosinte, Zea diploperennis Iltis, Doebley and Guzman, and gamagrass, Tripsacum laxum Nash, have been crossed to produce a fully fertile bridge species that may improve corn, Zea mays L., by conferring beneficial traits such as pest resistance and drought tolerance. Z. diploperennis (hereinafter referred to as diploperennis), was an unknown wild relative of corn until it was discovered, apparently on the threshold of extinction, in the mountains of Jalisco, Mexico in the late 1970's. It is in the same genus as corn, has the same chromosome number as corn (n=10), and hybridizes easily with it. Gamagrass is a more distant relative of corn with a different gametic chromosome number (n=18), and varying ploidy levels ranging from 2n=36 to 2n=108. Other species of gamagrass, namely T.dactyloides and T. floridanum, have been crossed with corn and hybrids are male sterile and essentially female sterile. Attempts to cross Tripsacum and annual teosinte, the closest relative of corn that most scientists believe is its wild progenitor, failed. Many plant breeders believe that gamagrass has significant potential for improving corn by expanding its genetic diversity.

In 1985, crosses were made by pollinating diploperennis with pollen from Eastern gamagrass, T. dactyloides, U.S. Plant Pat. No. 6,906 for ‘Sun Dance’, the hybrid from that cross, was issued Jul. 4, 1989. In April, 1985, the reciprocal cross to tetraploid Tripsacum was made using Z. diploperennis as pollen donor and T. dactyloides as pollen recipient, and U.S. Plant Pat. No. 7,977 for ‘Tripsacorn’, the hybrid from that cross, was issued Sep. 15, 1992. In January, 1988, Z. diploperennis was pollinated with pollen from a diploid (2n=36) T. dactyloides. U.S. Plant Pat. No. 9,640 for ‘Sun Star’, the hybrid from that cross, was issued Sep. 3, 1996.

On Jan. 26, 2002, Z. diploperennis was pollinated with pollen from Tripsacum laxum. The seed, planted May 27, 2002, germinated and grew into a normal, fully fertile plant named ‘Venus Express’ that is a perennial and produces viable fruits year-round in the greenhouse. The new plant has been propagated by rhizome divisions, cuttings, and anther culture. Various corn lines crossed with ‘Venus Express’ have produced fertile corn plants. This diploperennis-Tripsacum recombinant, like the recombinants ‘Sun Dance’, ‘Tripsacorn’, and ‘Sun Star’, provides a genetic bridge for moving genes from Tripsacum into corn using conventional plant breeding methods, and thereby establishing a link between these wild grasses and modern corn that may be beneficial in corn improvement breeding programs. Unique propagation of this plant through successive generations by means of rhizome divisions, cuttings, and anther culture have demonstrated that the new plant has not only retained the continuous and abundant production capability, but also that its distinguishing characteristics hold true from generation to generation and appear to be firmly fixed. Examination of the roots revealed that ‘Venus Express’ has well developed air passages referred to as aerenchyma. This property provides roots oxygen so they can tolerate flooded soils. It also allows the roots to grow deep below the hardpan, a characteristic that conveys good drought tolerance along with acid soil and aluminum tolerance, and gives the plant potential for use in bioremediation. Propagation has taken place in Durham, N.C. All activities including making the cross pollination between the two genera, growing the respective recombinant plant from a seed, and further reproducing the plant asexually from rhizomes, stem cuttings, and anther culture, took place in a greenhouse in Durham, N.C.

DESCRIPTION OF ILLUSTRATIONS

This new corn plant is illustrated by the accompanying full color photographs that include:

FIG. 1, a fully grown plant showing the characteristic habit of many culms growing from the base;

FIG. 2, a closeup of culms enwrapped by the red sheath;

FIG. 3, a closeup of the ciliate leaf margins;

FIG. 4, a rhizome;

FIG. 5, a distichously arranged pistillate spike with red styles, and

FIG. 6, mature seeds;

FIG. 7, rooted cuttings;

FIG. 8, a tassel branch showing a plantlet growing out of an anther, and

FIG. 9, a tassel with multiple plantlets growing out of anthers.

COMPARISON TO ‘SUN DANCE’, ‘TRIPSACORN’ AND ‘SUN STAR’

Although this plant is similar to ‘Sun Dance’, ‘Tripsacorn’, and ‘Sun Dance’, it is distinctive from these plants because it was derived from crossing Z. diploperennis with T. laxum (2n=72), section Fasciculata; whereas ‘Sun Dance’ and ‘Tripsacorn’ hybrids were derived from crossing Z. diploperennis with a tetraploid T. dactyloides (2n=72), section Tripsacum, and ‘Sun Star’ was derived from crossing Z. diploperennis with a diploid T. dactyloides (2n−36), section Tripsacum. In contrast to the sessile pair of staminate flowers characteristic of T. dactyloides and section Tripsacum in general, T. laxum has one sessile and one pedicillate staminate member of the pair of staminate flowers, which is characteristics of the Tripsacum members of section Fasciculata. Venus Express is distinguished from the three diploperennis-T. dactyloides recombinants by its smaller leaves, more numerous culms, and year-round flowering. T. laxum and diploperennis are used as forage plants. The greater number of culms and year-round flowering of Venus Express are traits not characteristic of either parent that give it added value as a forage crop in addition to its capacity to serve as a genetic bridge to move T. laxum genes into corn.

INVENTORS:

Eubanks, Mary W.

THIS PATENT IS REFERENCED BY THESE PATENTS:
Patent Priority Assignee Title
THIS PATENT REFERENCES THESE PATENTS:
Patent Priority Assignee Title
5750828, Nov 04 1987 Method and materials for conferring tripsacum genes in maize
PP9640, May 31 1995 Corn plant named `Sun Star`
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