Reexamination Certificate
2002-03-05
2003-04-15
Carr, Deborah D. (Department: 1624)
C554S224000, C426S622000
Reexamination Certificate
active
06547711
ABSTRACT:
FIELD OF THE INVENTION
This application relates to improved oilseed Brassica plants and the seeds obtained from these plants, wherein such seeds have decreased fiber and increased oil and protein content. This invention also relates to methods for decreasing fiber content and increasing seed oil and protein levels in seeds from oilseed Brassica plants.
BACKGROUND OF THE INVENTION
The term rapeseed is used to refer to a number of oilseed crop plant species within the genus brassica, including
B. napus, B. rapa
(syn. campestris),
B. juncea
and B.
carinata
. Spring and winter lines have evolved for
B. napus
and
B. rapa
, while only spring varieties of
B. juncea
are known.
B. napus
winter varieties are grown predominantly in northern Europe, China, and the northwest United States, whereas spring varieties predominate in Canada, northwest China, Denmark, and parts of Sweden.
B. rapa
has a shorter growing season than
B. napus
and this trait makes the spring varieties of this species suitable for the more severe climates of Sweden, Finland and Western Canada.
B. juncea
is grown extensively on the Indian subcontinent, while
B. carinata
is grown primarily in Ethiopia.
The taxonomic structure among members of the Brassica genus is complicated, as many of these species are able to cross pollinate naturally. Thus, there is a large amount of genetic variation available to oilseed Brassica breeders. The oilseed brassica species,
B. napus, B. rapa
, and
B. juncea
are closely related to one another, as well as to
B. nigra, B. oleracea
, and
B. carinata
. Cytological evidence indicates these species all originate from an extinct common ancestor which had 5 or 6 chromosomes, and that the high chromosome number Brassica species (
B. napus, B. juncea
, and
B. carinata
) originated as amphidiploid hybrids from combinations of low chromosome number species (
B. nigra, B. rapa
, and
B. oleracea
). The knowledge of the . relationship between the various Brassica species creates possibilities for producing new synthetic oilseed Brassica material, as well as for transferring traits between the various related Brassica species.
Seedcoat color in rapeseed may be different depending on the particular species and variety of Brassica. Coat color is generally divided into two main classes, yellow or black (or dark brown), although varying shades of these colors, such as reddish brown and yellowish brown are also observed. Seeds with yellow coats have been found to have thinner hulls and thus less fiber and more oil and protein than varieties with dark color seed coats. Yellow-seeded rapeseed varieties are common in Asian countries, and in China, there is an abundance of yellow-seeded cultivars in production rapeseed, particularly in
B. juncea
and
B. rapa
varieties.
In order to improve the nutritional qualities of rapeseed oil, varieties have been developed which contain low erucic acid levels, as well as low glucosinolate levels. These varieties of
B. napus
and
B. rapa
have been termed “canola” by the Canadian breeders involved in their development, and the oils from these varieties are well accepted in the global vegetable oil markets. On the world markets, rapeseed oil does not derive from a particular species, and both high erucic acid and low erucic acid oils contribute to the edible oil supply. In 1996, about 14% of the global edible oil supply was from oilseed Brassica varieties.
The high protein content in its seed meal also makes rapeseed meal a valuable livestock feed, although the relatively high fiber content decreases its digestibility and decreases the value as an animal feed. Also, the presence of glucosinolates can decrease the value of the meal due to the deleterious effects of glucosinolates on growth and reproduction of livestock.
Improved oil and protein levels are primary objectives of rapeseed breeding programs. Thus, introduction of a yellow seed coat trait into canola varieties is desirable, in the interest of providing improvements in both the seed oil and protein levels. Integration of genes controlling seed pigmentation from related Brassica species into valuable oilseed Brassica varieties, such as canola varieties, is complicated by the fact that multiple recessive alleles are involved in the inheritance of yellow seed coats in presently available yellow coat lines.
Accordingly, there is a need in the art for yellow coat oilseed Brassica lines in which the trait for yellow seed coat can be easily transferred to other oilseed Brassica plants, and in particular to canola varieties, these lines can be used to accelerate the development of oilseed Brassica cultivars with improved oil, protein, and fiber contents.
SUMMARY OF THE INVENTION
Rapeseeds and oilseed Brassica plants producing rapeseeds, which have a yellow-seed coat are provided wherein the yellow-seed coat color is controlled by a single locus mutation. The rapeseed is characterized by having high levels of seed oil and protein and low levels of fiber and glucosinolate. The rape plants grown from the seed are also early maturing.
The plants and seed are useful for producing improved canola and rape varieties and for providing a source of valuable meal and oil products.
DETAILED DESCRIPTION OF THE INVENTION
The invention is drawn to rapeseeds which have a yellow-seed coat, as well as to the plants producing such rapeseeds. The yellow-seed coat color is controlled by a single locus mutation. Thus, the trait can be easily transferred to desired lines without the complications associated with multiple gene inheritance.
Yellow seeds have a considerably thinner seed coat than black and brown ones. The thinner seed coat results in a reduced fiber content in the meal and an associated increase in seed oil and protein content as compared with normal levels of oil and protein. In seeds of the invention, seed oil levels are increased at least about 3%, preferably at least about 5%, more preferably at least about 10%.
Yellow-seeded genotypes generally have higher oil and protein concentrations in their seeds. The yellow-coated seeds of the invention display an increase in protein concentration. Protein levels are increased at least about 10%, preferably about 20%, more preferably about 30%.
Yellow-seeded genotypes typically show a decrease in fiber content. The yellow-coated seeds of the invention have decreased fiber content of at least about 2%, preferably about 5%, more preferably about 8%.
The seeds of the invention also exhibit a decrease in glucosinolate levels. Glucosinolate levels are decreased at least about 10%, preferably about 15%, more preferably about 20%. This reduction is important for utilizing the seed mean as animal feed.
Plants from the rapeseeds of the invention mature earlier than the parent lines from which these plants were developed. Earlier maturing varieties are particularly useful. For example, they find use where a short growing season is needed to avoid an environmental stress such as cold or drought or alternatively where multiple crops are grown. Various multiple cropping sequences are needed, particularly in China and India. In Western Canada, B. campestris varieties maturing in less than 100 days are required to escape frost damage. Additionally, short-duration rapeseed varieties are needed in Southern Australian to avoid late-season drought stress. By early maturing is intended that the plants mature at least about 2 days, preferably at least about 5 days, more preferably at least about a week or more early as compared to the parent lines from which the earlier maturing plant lines were developed.
Methods are available in the art for the production of plants and rapeseed of the invention. Generally, plant cells can be mutagenized and selected for those exhibiting the desired trait. Alternatively, the trait can be crossed into desired varieties using standard genetic methods known in the art.
For purposes of the invention, for mutagenesis and selection, plant cells are selected that are capable of regeneration such as seeds, microspores, ovules, pollen, vegetative part
Calgene LLC
Carr Deborah D.
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