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
1999-05-28
2001-11-20
Benzion, Gary (Department: 1649)
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
C800S260000
Reexamination Certificate
active
06320104
ABSTRACT:
The present invention relates to a new head form characteristic in lettuce, to use of the new characteristic in the development of new types of lettuce plant which differ morphologically from the lettuce plants known heretofore, and to heads of lettuce which contain this characteristic and thereby differ morphologically from known heads of lettuce.
A great diversity of lettuce varieties exists nowadays. At present more than a thousand cultivars are known which can be divided roughly into the groups butterhead lettuce, iceberg lettuce, batavia lettuce, cos lettuce or romaine lettuce, oakleaf lettuce and lollo lettuce. This classification is based on the morphology of the leaf and the degree of head forming. However, other classifications are used in addition to this one. The UPOV list of descriptions of lettuce varieties thus refers for instance to the following six groups: butterhead lettuce, crisp lettuce, cos lettuce, “Grasse” lettuce, cutting lettuce and stem lettuce.
The known head lettuce, also known as butterhead lettuce, and the iceberg lettuce have the drawback that in these types of lettuce the outer leaves of a head of lettuce are clearly much larger than the inner leaves. For applications wherein cut or peeled whole leaves are used, such as in sandwiches, on hamburgers and the like, leaves of the most uniform possible size are preferred. In the case of heads of lettuce with a clear heterogeneity in leaf size, such as the head-forming lettuce types butterhead lettuce or head lettuce, iceberg lettuce, batavia lettuce, cos lettuce or romaine lettuce, and “Grasse” lettuce, the outer large leaves will either be unusable or will always have to be reduced in size before use by means of cutting or tearing. Browning occurs quite quickly on the cut or torn edges whereby the lettuce loses its attractive appearance and rotting can also occur more rapidly. Similar problems occur in automatic processing into cut lettuce.
It is the object of the invention to provide a new type of lettuce with which the above described problems can be avoided.
According to the invention a type of lettuce is now provided which, in comparison with the known types of lettuce, comprises significantly more leaves of substantially equal dimensions at the ready-to-harvest stage. “Of substantially equal dimensions” is understood to mean that the leaves of this so-called multileaf type have on average a shorter length and lower weight relative to a normal lettuce plant with a comparable leaf morphology and comparable plant weight.
In the case of butterhead lettuce of the new type, due to the significantly higher number of leaves and the average shorter leaf length, a large number in absolute sense, and a large part in relative sense, of the harvestable leaves falls within the size of 4 to 12 cm leaf length (see Table 1).
Lamb's lettuce of the new type (
Valerianella locusta L
.) likewise has more leaves which have a smaller leaf size than lamb's lettuce plants not having the characteristic according to the invention (see Table 4).
“Significantly more leaves” is understood to mean in this case at least 1½ times as many as a type with a comparable leaf morphology at equal (or comparable) plant weight, preferably at least twice as many, more preferably at least 2½ times as many, most preferably at least 200 leaves of substantially equal dimensions.
The lettuce provided according to the invention is per se a new type but can have different leaf morphologies which in turn originate from other types of lettuce. The type of lettuce according to the invention is however always “multileaf” lettuce.
The characteristic “significantly more leaves of substantially equal dimensions” is a new head form characteristic and will be further designated “multileaf” characteristic and likewise form part of the invention. The presence of the multileaf characteristic in a lettuce plant can be determined simply by comparing the total number of leaves of a ready-to-harvest lettuce plant suspected of possessing the multileaf characteristic with the total number of leaves of a ready-to-harvest lettuce plant which is comparable in respect of leaf morphology and plant weight but which certainly does not possess the multileaf characteristic (control plant). When the suspected multileaf lettuce plant has at least 1½ times as many leaves as the control plant, it can be stated that the multileaf characteristic is present. In such plants use is in that case made of the characteristic according to the invention. Use has also been made of the characteristic in the manufacture of such plants. These types of use also form part of the invention.
The multileaf characteristic means in fact that plants have a genetic constitution which enhances the occurrence of fasciation at a determined stage of the vegetative growth. Fasciation in butterhead lettuce occurs at a relatively early stage of the vegetative growth, while in lamb's lettuce the characteristic is expressed only at a later stage of growth.
Fasciation, also referred to as band formation, is a per se undesired phenomenon which can occur in many types of vascular plants. It was already described in 1948 by White in “Fasciation”, Bot. Rev. 14, 319-358 (1948). Fasciation in lettuce is characterized by the apex of a stem becoming increasingly wide when it begins to lengthen. A cone-shaped apex normally results. In the case of fasciation however, a flat, wide and comb-like (grooved) band of meristematic tissue is formed. It is known that fasciation in lettuce has a genetic basis and is inherited recessively (Haque & Godward, Genetica-Iberica 38, 139-155 (1986)) or additively (Eenink & Garretsen, Euphytica 29, 653-660 (1980)). In addition, influences of environmental conditions on the expression of fasciation have also been described (Eenink & Garretsen, supra).
Fasciation in lettuce is a phenomenon which has been known for some time and which was long considered mainly as disadvantageous, because lines submitted for registration under the UPOV Treaty often did not react uniformly to fasciation and because fasciation hinders seed production. Fasciation does however also have a positive side, since fasciated plants are slow-bolting, which is a particular advantage for greenhouse varieties in the summer period.
According to the invention the phenomenon of fasciation has now been used to arrive at an entirely new type of lettuce. By specific selection it has been possible to increase, respectively advance the degree and the time of fasciation, whereby a fasciated apex is already formed, for instance in butterhead lettuce, at a very early stage of the vegetative growth. The final lettuce plant hereby acquires a rosette-like head which is built up of a very large number of leaves of substantially equal size on a greatly enlarged stem base.
In lamb's lettuce the characteristic occurs later, but at the harvestable stage the differences from lamb's lettuce plants not displaying the characteristic is very clearly visible.
The advantage of the new lettuce plants according to the invention is that a very large number of leaves of substantially equal dimensions can be cut from one head of lettuce. Moreover, owing to the greatly increased circumference of the stem, the leaves can be cut from the stem at the location of their petiole more easily than in lettuce types with a comparable leaf morphology. Only a limited cut surface hereby results and the leaves them-selves remain intact.
Owing to their substantially equal dimensions, the leaves are particularly suitable for use on for instance sandwiches or hamburgers, or in pre-cut salads.
In lamb's lettuce the multileaf characteristic results in a different manner of growth. In lamb's lettuce not displaying the multileaf characteristic (further referred to as “normal” lamb's lettuce) the leaves are crossed in pairs. In the multileaf lamb's lettuce the leaves are placed in groups as rosettes. The head consists of large numbers of such rosettes.
Described and shown in the accompanying examples and f
Berg Jurjen Johannes
Moor Cornelis Marinus
Benzion Gary
Kimball Melissa L.
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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