Multicellular living organisms and unmodified parts thereof and – Plant – seedling – plant seed – or plant part – per se – Higher plant – seedling – plant seed – or plant part
Reexamination Certificate
2001-08-06
2003-04-29
Fox, David T. (Department: 1638)
Multicellular living organisms and unmodified parts thereof and
Plant, seedling, plant seed, or plant part, per se
Higher plant, seedling, plant seed, or plant part
C435S410000, C435S421000, C435S430000, C435S430100, C800S260000, C800S278000, C800S279000, C800S298000, C800S300000, C800S301000, C800S302000
Reexamination Certificate
active
06555735
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a new and distinctive Romaine lettuce (
Lactuca sativa
) variety, designated HMX 7555. There are numerous steps in the development of any novel, desirable plant germplasm. Plant breeding begins with the analysis and definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possess the traits to meet the program goals. The goal is to combine in a single variety or hybrid an improved combination of desirable traits from the parental germplasm. These important traits may include increased head size and weight, higher seed yield, improved color, resistance to diseases and insects, tolerance to drought and heat, and better agronomic quality.
Practically speaking, all cultivated forms of lettuce belong to the highly polymorphic species
Lactuca sativa
that is grown for its edible head and leaves. As a crop, lettuces are grown commercially wherever environmental conditions permit the production of an economically viable yield. Lettuce is the world's most popular salad. In the United States, the principal growing regions are California and Arizona which produce approximately 287,000. acres out of a total annual acreage of more than 300,000 acres (USDA, 2001). Fresh lettuces are available in the United States year-round although the greatest supply is from May through October. For planting purposes, the lettuce season is typically divided into three categories, early, mid and late, with the coastal areas planting from January to August, and the desert regions from August to December. Fresh lettuces are consumed nearly exclusively as fresh, raw product, occasionally as a cooked vegetable.
Lactuca sativa
is in the Cichoreae tribe of the Asteraceae (Compositae family). Lettuce is related to chicory, sunflower, aster, dandelion, artichoke and chrysanthemum. Sativa is one of about 300 species in the genus Lactuca. There are seven different morphological types of lettuces: the Crisphead group includes the iceberg and batavian types. Iceberg lettuce has a large, firm head with a crisp texture and a white or creamy yellow interior. The Batavian lettuce predates the iceberg type and has a smaller and less firm head. The Butterhead group has a small, soft head with an almost oily texture. The Romaine, also known as cos lettuce, has elongated upright leaves forming a loose, loaf shaped head. The outer leaves are usually dark green. The Leaf lettuces comes in many varieties, none of which form a head. The next three types are seldom seen in the United States: Latin lettuce looks like a cross between romaine and butterhead; stem lettuce has long, narrow leaves and thick, edible stems. Oilseed lettuce, finally, is a primitive type grown for its large seeds that are pressed to obtain oil.
Lactuca sativa
is a simple diploid species with nine pairs of chromosomes (2n=2x=18). Lettuce is an obligate self-pollinating species. This means that the pollen is shed before stigma emergence, assuring 100% self-fertilization. Since each lettuce flower is an aggregate of about 10-20 individual florets (typical of the Compositae family), manual removal of the anther tubes containing the pollen is tedious. As such, a modified method of misting to wash the pollen off prior to fertilization is needed to assure crossing or hybridization. About 60-90 min past sunrise, flowers to be used for crossings are selected. The basis for selection are open flowers, with the stigma emerged and the pollen visibly attached to the single stigma (about 10-20 stigma). Using 3-4 pumps of water from a regular spray bottle, the pollen grains are washed off with enough pressure to dislodge the pollen grains, but not enough to damage the style. Excess water is dried off with clean paper towels. About 30 min later the styles should spring back up and the two lobes of the stigma are visibly open in a “V” shape. Pollens from another variety or donor parent are then introduced by gently rubbing the stigma and style of the donor parent to the maternal parent. Tags with the pertinent information on date and pedigree are then secured to the flowers
Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used commercially (e.g., F
1
hybrid cultivar, pureline cultivar, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants. Popular selection methods commonly include pedigree selection, modified pedigree selection, mass selection, and recurrent selection.
The complexity of inheritance influences choice of the breeding method. Backcross breeding is used to transfer one or a few favorable genes for a highly heritable trait into a desirable cultivar. This approach has been used extensively for breeding disease-resistant cultivars. Various recurrent selection techniques are used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross
Each breeding program should include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, but should include gain from selection per year based on comparisons to an appropriate standard, overall value of the advanced breeding lines, and number of successful cultivars produced per unit of input (e.g., per year, per dollar expended, etc.).
Promising advanced breeding lines are thoroughly tested and compared to appropriate standards in environments representative of the commercial target area(s) for three years at least. The best lines are candidates for new commercial cultivars; those still deficient in a few traits are used as parents to produce new populations for further selection.
These processes, which lead to the final step of marketing and distribution, usually take from eight to 12 years from the time the first cross is made. Therefore, development of new cultivars is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction.
A most difficult task is the identification of individuals that are genetically superior, because for most traits the true genotypic value is masked by other confounding plant traits or environmental factors. One method of identifying a superior plant is to observe its performance relative to other experimental plants and to a widely grown standard cultivar. If a single observation is inconclusive, replicated observations provide a better estimate of its genetic worth.
The goal of plant breeding is to develop new, unique and superior lettuce cultivars. The breeder initially selects and crosses two or more parental lines, followed by repeated selfing and selection, producing many new genetic combinations. The breeder can theoretically generate billions of different genetic combinations via crossing, selfing and mutations. The breeder has no direct control at the cellular level. Therefore, two breeders will never develop the same line, or even very similar lines, having the same lettuce traits.
Each year, the plant breeder selects the germplasm to advance to the next generation. This germplasm is grown under unique and different geographical, climatic and soil conditions, and further selections are then made, during and at the end of the growing season. The cultivars that are developed are unpredictable. This unpredictability is because the breeder's selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with mi
Fox David T.
Harris Moran Seed Company
Jondle & Associates PC
Kruse David H
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