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Vitis Species Plant Materials. Gerard Logan, Michel Meunier. Introduction. Ampelography Taxonomy Methods of grouping vines History Why identify vines Requirements for correct identification. Binomial taxonomy. Carolus Linnaeus (1707-1778) Swedish physician and botanist
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Vitis Species Plant Materials Gerard Logan, Michel Meunier
Introduction • Ampelography • Taxonomy • Methods of grouping vines • History • Why identify vines • Requirements for correct identification
Binomial taxonomy • Carolus Linnaeus (1707-1778) • Swedish physician and botanist • Developed the binomial system of naming organisms according to genus and species • Filed species into a hierarchy of increasingly general categories.
Grapevine taxonomy • Family Vitaceae Genus Vitis • Two unofficial Subgenera Vitis and Muscadiniae. • For breeding purposes the various species of Vitis are divided into geographic areas of origin • The taxonomy of the grapevine is problematic, as much confusion exists as to the number of genera present within Vitaceae, and the number and correct identification of species within the genera.
Botanical groups • Grape cultivars grouped into convar (proles) • Based on geographic origin & associated morphological characteristics • Convar orientalis • Subconvar antasiatica • Subconvar caucasica • Convar pontica • Subconvar georgica • Subconvar balcanica • Convar occidentalis
Fruit maturation • Proposed by Victor Pulliat (Frenchman) • Based on time of maturation relative to Chasselas blanc • Ripening groups or epochs divided by 10-15 day intervals
Ampelography • The science of description and identification of grapevine cultivars from the genus Vitis.
History • Initiated by introduction of American species to Europe • Initial ampelographies based on fruit characteristics • Hermann Goethe proposed using measurements of leaf vein angles • Idea developed by Louis Ravaz in 1902 • Krimbas used berry and seed length ratios • Pierre Galet developed Ravaz biometry of leaves • Based on leaf structure and indument (hairiness)
Other methods • Chemical/analytical • Genetic profiling • Chemical composition of berries • Electrophoresisanalysis • Molecular biology • DNA
Why identify vines? • So we can identify them! • Requirements of descriptors • Easily to record objectively • Constant between varieties and regions • Significantly different • Hard to satisfy all requirements • Characteristics least influenced by environment are preferred
Why identify cultivars? • Grape grower • Wine maker • Consumer • Industry
Important NZ cultivars Cultivar 1995 2003 • Muller Thurgau 885 256 • Chardonnay 1,385 3,515 • Sauvignon Blanc 936 4,516 • Chenin Blanc 145 108 • Gewurztraminer 124 197 • Riesling 289 653 • Muscat Varieties 204 134 • Semillon183 257 • Reichensteiner98 59 Cultivar 1995 2003 Pinot Gris 22 316 Cabernet Sauvignon 526 741 Pinot Noir 415 2,624 Pinotage66 82 Merlot 282 1,249 Cabernet Franc 80 180 Syrah 14 134 Malbec11 152 Other & Unknown 445 627
Classification Keys • Galet’s key is a classification key • Based on morphological characters • Key = a device for easily identifying an unknown specimen by a sequence of choice between two or more statements usually diagnostic • Dichotomous = two contrasting choices • Quantitative characters • Recorded visually or sensory • Quantitative characters • Measured or weighed • Timing is important
Ampelography Visual Classification of Grapevines
Overview • Various classification systems • Ampelography • Galets key • Distinguishing characteristics
Systematic approaches • Most systems use morphological characteristics of vegetative and reproductive organs • Both qualitative descriptions and quantitative measurements
OIV descriptor list for grapevine varieties and Vitis sp. • Listed characteristics have been standardised • Uses a common basis for conservation, description and evaluation of grapevines • Uses distinguishing and productivity characteristics
Qualitative characteristics • Each character is provided with an OIV # and described with words followed by a certain figure • These notes describe the characteristic
Examples • Code # 001 Young shoot: form of tip 3 = closed 5 = half opened 7 = opened Code # 065 Mature leaf: size 1 = very small 3 = small 5 = medium 7 = large 9 = very large
Alternative characteristics • Distinguish between absent (1) or present (9) • If it is necessary to distinguish between complete absence and different degrees of presence, the characteristics is split into another characteristic with 9 notes
Examples • Code # 045 Resistance to Plasmopara viticola 1 = absent 9 = present Code # 016 Tendrils: distribution on the shoot 1 = discontinuous on the shoot (2 or less) 9 = subcontinuous or continuous (3 or more)
Quantiative characteristics • Measurable on a one dimensional scale • Show continuous variation from one extreme to another • Divided into notes 1 to 9, where 1-3 are weak expression & 7-9 are strong • Which parts of the scale or notes are chosen for the definition of the single states, depends on the variation extent of the characteristic
Example • Code # 452 Degree of resistance to Plasmopara(leaf) 1 = very little 3 = little 5 = medium 7 = high 9 =very high
Observation of characteristics • Qualitative characters recorded visually • Quantitative characters are measured • Further details are listed • Times of some observations are specified • Resistance to disease is to be assessed under field trial (1-3 susceptibility / 7-9 resistance)
Classification keys • Key is an analytical device for easy identification of an unknown plant or cv by a sequence of choices between two or more statements • Normally diagnostic • Most dichotomous
Galet • Galet’s key is a classification key • Based on morphological characters • Key = a device for easily identifying an unknown specimen by a sequence of choice between two or more statements usually diagnostic • Dichotomous = two contrasting choices • Qualitative characters • Recorded visually or sensory • Quantitative characters • Measured or weighed • Timing is important
Other systems • Orffer (South African) produced a similar key for red and white grapes • Hillebrand (German) has developed a similar system • These two and that of Galet do not always concur in definitions of characteristics
Sampling • Awareness of sampling is important for some descriptors • Freshly collected samples are preferred • Collect a sample with cane, leaves, fruit or flowers where possible • Leaves should be from beyond the 6th node (Galet)
Summary • Three types of methods: • Classification keys • Precise descriptions • Using distinguishing features Important to define the method • Influences on method may be: • Objective • Subjective • For consistency definition & development are necessary for: • Definition of methods • Collection • Diagnostic characters • Biometrical methods
Practical Ampelography Grapevine Identification