lllustrated OUTLINE FOR USE IN TAXONOMIC DESCRIPTION OF SUGARCANE VARIETIES

Transcription

1 PAPER lllustrated OUTLINE FOR USE IN TAXONOMIC DESCRIPTION OF SUGARCANE VARIETIES Pathologist, Division of Sugar Plant Investigations Bureau of Plant Industry, United States Department of Agriculture Washington, D. C. The outline recommended is an adaptation of the variety questionnaire by the International Society of Sugar Cane Technologists. Its scope has been broadened and details have been added to facilita~e the comparative study of character variations within a certain group or collection. Of assistance is the incorporation of illustrations of type characters such as ligule, dewlaps and auricles. These illustrations not only simplify the taking of notes but often serve to refresh one's memory in the salient points of sugarcane morphology. If possible, all characters should be studied and illustrations prepared from fresh material. In noting the color of the stalk, mature and exposed internodes which have not yet become faded should be used. The color of the flesh in a freshly-made cross section soon changes and should be recorded immediately. Only fully developed eyes should be chosen for comparison, preferably those coming from beneath matured leaves which are still attached to the plant. The dewlap pattern characteristic of the variety shows most clearly in mature or almost fully grown leaves; because of a general tendency in cane leaves toward asymmetry, only the dewlaps on related sides should be compared. ~uricies attain their full size early but they also deteriorate soon; for this reason, descriptions should be made from relatively young material. Hair groups on leaf blade, leaf sheath, and prophyllum should be studied on both young and old organs because there occur varieties in which certain hairs are deciduous while others attain greater prominence in the mature organ. The epidermis should be stripped by heating parts of leaves or stalk in concentrated nitric acid. The blade epidermis strips rather readily and care should be taken not to prolong the treatment; the epidermis of the stem Stalk Structures. is more resistant and often requires prolonged

2

3 Sheath: Shedding: retained... shed when dry... partly shed... Clas$ing: tightly... loosely... Color:.... Waxiness:.... Length:.... Base: straight... saccate... oblique... Overlying margin: decurrent.... apperidaged... SHEATH SCAR: Prominence: prominent... inconspicuous... Shape: straight... oblique..... BLADE JOINT: (inner surface-throat; outer surface-collar composed of the 2 dewlaps). Dewlaps: color... waxiness... shape... size... Ligule: shape... symmetry... slope... height... Auricles: Inner auricle: shape.... size... outer auricle: shape... size... EPIDERMIS: Stem: pattern... stomates... hairs... Upper blade surface: bulliform bands... spines... velvety hairs.... Lower blade surface: spines... velvety hairs... Outer sheath surface:... COLOR:... SIZE: length.... diameter.... location of max. diameter..:... ALIGNMENT: aligned.... zigzag... crooked.... SHAPE: a) cylindrical... b) tymescent... c) bobbin-shaped... d) conoidal... e) obconoidal... f) concave on bud side.... g) tumescent on bud side.... h) shouldered at base opp. bud... SURFACE: smooth... blotched... growth cracks... corky cracks.... GENERAL BLOOM (wax): amount... 'distribution... color... WAX BAND: Shape: a) cylindrical... b) obconoidal... c) recessed under bud... d) constricted... Base line: distinct.... merging with general bloom.... I Width: broad... medium... narrow... Amount of wax: heavy light, I 18

4 BUD FURROW: Prominence: inconspicuous width in mm. prominent length INTERNAL TISSUE: Color: periphery center Texture: solid pithy in center with a cavity Anatomical structure: Rind: vascular bundles per mm. sheath development Central tissue: density of bundles lignification of parenchyma EPIDERMAL STRUCTURE: Short-cell groups (cork and silica cells) : numerous sparse Cork cells: Shape: a) squarish. b) reniform c) trapezoidal d) short-pointed e) long-pointed f) elongated rectangular Occurrence: solitary in groups or two or more % of solitary cork cells Long cells: straight bent width in p Stomates: absent sparse abundant EPIDERMAL PATTERN: 1) Cork and silica cells in pairs; cork cells reniform or squarish 2) Silica cells wanting or very sparse 3) About 50% of silica cells wanting, otherwise like pattern No. 1 4) A preponderance of long- and short-pointed cork cells 5) A preponderance of very narrow elongated-rectangular cork cells 6) Cork and silica cells in multiple pairs NODE GROWTH RING: Color: Long cells: straight bent width in p Shape: straight arched on bud side irregular Contour: flush swollen constricted ROOT BAND: Color:... Width: at bud side... at side opposite bud... Shape: a) cylindrical... b) tumescent... c) constricted... d) conoidal.... e) obconoidal..... f) tumescent on bud side... g) depressed... ROOT PRIMORDIA: Number of rowd: Uniformity of rows: uniform irregular Density in row: crowded semi-crowded sparse 119

5 INDIVIDUAL ROOT BUDS: Color: center surrounding border.... Shape: round... oval.. Contour: flush..... swollen.. depressed.... Size: large... small.... Dormancy: dormant. tendency to sprout in the field... BUD membranaceous margin- of win& COLOR: Scale: young bud... old bud... Wing: young bud... old bud... POSITION RELATIVE TO STALK: flush.... depressed..... protruding.... INSERTION: above leaf scar... at scar... extending sac-like below scar..... HEIGHT: reaching growth ring... not reaching growth ring... extending beyond growth ring... SIZE: large... intermediate... small... FORM: General shape: short... long... broad.... narrow... i.....: plump.... flat....:... Form pattern: a) oval... b) ovate... c) obovate... d) rhomboid... e) pentagonal... f) round... g) elongate triangular..... MEMBRANACEOUS MARGIN: Width: uniformly narrow.... wider at base.... wider at apex.... Basal appendange: Prominence: inconspicuous... prominent... absent... Insertion: low... medium... high... Lateral appendages: number.... location... prominence.... WING: Insertion: below middle of bud at middle above middle

6

7 ' Surface: smooth..... wrinkled.... Size and shape: wide... medium... narrow... wider at base... narrower at base... lobed... Edges: entire..... notched at base...:..... emarginate throughout... Tip: Form: a) broadly triangular... b) crescent-shaped.... c) truncate... d) mucronate... e) round-pointed...::... f) sharp-pointed... Margin: entire... notched... cleft... dentoid... VENATION: straight and parallel.... converging at apex.... semi-radial... radial... GERM PORE: apical.... subapical.... central.... LEAF BLADE TEXTURE: smooth... rough...: leathery...'.. THICKNESS: thick..... thin.....:. VEINS: ~ ~CO~S~~CUOUS... prominent... MIDRIB: Color: upper surface Cross section: massive lower surface flat STRUCTURE OF LOWER EPIDERMIS: Intercostal area: Width: total number of cell rows rows of stomates Hairs: 2-celled hairs spines velvety pubescence (gr. 67)... Vein area: Width: rows of cells... cell pattern... Spines: absent...:... scarce... abundant... in rows... Stomata1 grooves: absent... incompletely developed... prominent..... STRUCTURE OF UPPER EPIDERMIS: (a) Bulliform band: width in number of cell rows cell type... (b) Marginal band: Width: nu'mber of cell rows cell pattern Hairs: 2-celled hairs spines

8 1 (c) Stomate zone: number of rows 1 (d) Central zone: Width: number of cell rows cell pattern c Hairs: velvety pubescence (gr. 67) Strand of short cells in middle of central zone: Width of strand: number of cell rows Spines: small medium large. PUBESCENCE OF LEAF EDGE (gr. 53) : LEAF SHEATH LENGTH: average length in cm I OVERLYING decurrent appendaged not decurrent SHEATH JOINT (base of sheath) : Form: horizontal Color: outer surface SHEATH SCAR: Form: straight. oblique protuding under bud spreading under bud sagging under bud PUBESCENCE: Distribution of hairs: covering entire sheath hairs in groups sheath glabrous Dorsal patch (Jeswiet gr. 57) : Shape: lenticular linear irregular Extent: group begins cm. above node; group ends cm. below blade joint Density within group: dense medium sparse Hair type: long short hard soft appressed =k erect Lateral patch (gr. 60) : on overlying margin on underlying maron both margins Size: short long narrow broad,extent: group begins cm. above node; group ends cm. below dewlap Density wzthin group: dense medium sparse Hair type: long short hard soft appressed + erect Marginal fringe (gr. 56) : on overlying, underlying, or both margins Extent: group short group long hairs dense hairs sparse Hairs on surface of appendage (gr. 62) : Lashes on decurrent margin (gr. 64) : Cilia in axil of basal appendage: Peripheral fringe (gr. 59) : Dorsal tuft opposite bud (gr. 69) : Small black hairs extending into upper region of wax ring: L v

9

10 STRUCTURE OF EPIDERMIS: Intercostal area: Cell pattern:... Hairs: 2-celled hairs.... short spines..... large spines... Stomates: number of rows... Vein area: Cell pattern:... Spines: Location: marginal... central...:... scattered... Amount: absent... sparse... & abundant squarish SYMMETRY: both sides & alike... sides asymmetrical... COLOR: surface... margin... SIZE: large... medium... small... WAXY COVERING:... LOWER MARGIN: Slope: +horizontal somewhat sloping... steeply sloping... Outline: &straight... arched... --shaped... UPPER MARGIN: & straight... concave... convex... PUBESCENCE: Outer surface (gr. 58) : dense... medium... sparse... Inner surface: Short hairs (gr. 52) : Distribution: uniform & in bands Density: dense... medium... sparse... Extension of gr. 52 into midrib... Long hairs (gr. 51) I : / absent... limited to marginal tuft Distribution: covering about 1/3 of dewlap covering -+ entire dewlap extending into midrib

11 Amount: dense Arrangement: uniform LIGULE in bands Common patterns GENERAL SHAPE AND PATTERNO.: WIDTH: a) remains + uniform b) decreases gradually creases rapidly SLOPE: a) steep b) moderate c) ) horizontal FREE EDGE: a) entire b) notched and wavy c) flanges notched SYMMETRY: a) symmetrical b) asymmetrical MIDDLE PART OF LIGULE: Free edge: a) straight b) broadly curved c) round-pointed PUBESCENCE: Marginal fringe: (gr. 61) long sparse Dorsal hairs: (gr. 66) free sparse Hairs back of ligule on midrib: Deltoid or linear patch of short hairs: (gr. 63) Group of long hairs at base: (gr. 55) Single row of hairs at base of ligule: (gr. 65)

12 Common pattarns a) auricle inserted high b) auricle inserted low ) transitional types of auricles; 4) deltoid... 5) dentoid... 6) unciform... 7) calcariform...:... 8) lanceolate... 9) falcate... OCCURRENCE: Auricles wanting: Auricles of transitional type: Inner auricle pattern Auricles well developed: Inner auricle pattern LEVEL OF INSERTION: Symmetry: Both auricles inserted at same level Auricles inserted at different levels Height: Auricles inserted at level of dewlaps Auricles inserted below level of dewlaps outer auricle pattern outer auricle pattern PUBESCENCE: Marginal fringe (gr. 54) : absent partly developed extending over entire margin Surface covering: Hairs'are continuous with pubescence of sheath... Hairs limited to apical zone of auricle: Present on outer auricle (gr. 70) Present on inner auricle (gr. 71) Dr. Artschwager stated that for the past two years he had had occasion to study New Guinea importations and had made descriptions of 100 varieties. In a discussion brought up by Mr. Rosenfeld regarding the proper term to use in describing certain discolorations or mottled areas that occur regularly on

13 the rind of some cane varieties, Dr. Brandes said the condition is not a pathological one and that the discolorations appear as if the waxy surface had not developed. The rind has a roughened velvety surface instead of a smooth glossy feeling. He said he had never seen it until it appeared in a group of native canes from New Guinea, and there, in a half-dozen or more in a collection of 1000, the entire internode seemed to be involved, and the stalk, though healthy and full of juice, looked on the surface like an old, dead cane. Mr. Bregger mentioned that the blotching is one way of recognizing B.H. 10 (12). Dr. Artschwager stated that some people have not paid much attention to Jeswiet's hair groups but he found them intriguing. Hair groups are not helpful unless the quantity is great enough to be outstanding. For classification the upper epidermis of the leaf is more valuable than the lower. Dr. McIntosh asked if it is the intention of this paper to standardize descriptions and to use the given numbers throughout. Dr. Artschwager replied that he attempted to standardize it for people to use who are making descriptions, so each would know what the other means. Whether it is desirable to use Jeswiet's numbers is a question. For some varieties they are very useful but in other cases not so important. In the structure of the epidermis of the stem they are useful. These descriptions are not for a practical field man to use but for the technically trained person who makes crosses and who wants to compare varieties and trace relationships. ASSEMBLING AND EVALUATING WILD FORMS OF SUGARCANE AND CLOSELY RELATED PLANTS E. W. BRANDES, Principal Pa2hologist in Charge G. B. SARTORIS, Senior Pathologist and C. 0. GRASSL, Assistant Botanist Division of Sugar Plant Investigations, Bureau of Plant Industry, United States Department of Agriculture Washington, D. C. INTRODUCTION The process of improving sugarcane varieties by crossing wild cane, usually small and of unprepossessing appearance, with the larger, better-looking cultivated canes has come to be known as nobilization of the wild cane. The successful efforts to increase yields of sugar by this means is a relatively recent achievement of workers in the Netherlands East Indies and British India. The success of these attempts has focused attention upon this method and similar attempts are being made in other parts of the world. It is obvious that improvement of wild plants by selection is almost as old as mankind and essentially there is no novelty in the idea of nobilization except that it is a pause to reach back and