Varieties Cenicana Colombia
Stem
Some of its characteristics are:
Length: varies from less than 1 m (clones of Saccharum spontaneum) to more than 10 m (some clones of Saccharum robustum). Its length is measured from the ground to the
last visible neck.
Depending on their length, the stems can be:
- Short: less than 2.5 m
- Medium: 2.5 to 3.5 m
- Lengths: more than 3.5 m
Growth Habit: It is the direction that the stems take until they reach their
maturity, according to which they can be:
- Erect, when they grow vertically.
- Reclining, when they grow obliquely and touch or rest on the
neighboring strains. - Prostrate, when they touch the ground and their terminal part rises again.
Form: It refers to the arrangement that the stems follow in their development:
- Straight, when all the internodes are in the same direction.
- Curved, when they follow a simple curve.
- In zig-zag, when an internode changes its direction slightly or strongly
in relation to the following.
Diameter: It varies from 10 to 50 mm and can be:
- Very thin, less than 20 mm.
- Thin, 21 to 25 mm.
- Medium, 26 to 30 mm.
- Thick, 31 to 35 mm.
- Very thick, more than 36 mm.
Color: The most common colors are: yellow, red, purple, violet, and green. They can be of greater or lesser intensity and can be found alone or in mixtures. All colors lighten with the sun and their original color changes when the stem is mature, except for the color called sun red, which is located in a part of the stem.
knot where the protection of the sheath prevents the red color from showing.
Internode: It is the part of the stem between the leaf scar and the growth ring (Figure 1). From the scar down, the following are found:
- Waxy ring. In most varieties, it is formed by a thick layer of wax and can be well-defined or diffuse.
- Striae. Short, wide stripes.
- Bark or growth cracks. Longitudinal fissures that sometimes extend throughout the internode, are 5 to 10 mm deep, and are generally covered with a phellogen layer that protects them from infection or infestation. However, in areas with severe red glanders (Glomerella tucumanesis [Speg.] Arx and Müller) infection, the fungus can cause considerable damage. They can also be an entry point for the bacteria that produce dextrans.
- Bud canal. A depression behind the bud that extends to a greater or lesser extent along the internode and can be superficial or deep. In some varieties, it is barely visible and often disappears.
- Internode shapes. Internode shapes include: cylindrical, barrel-shaped, constricted, cone-shaped, oblong-cone-shaped, and curved (Figure 2).
Knot (Figure 1):
- The growth ring. This is the growth region of the internode and completely surrounds the node. It can be narrow, wide, prominent, or constricted.
- Root band. This is a more or less wide strip containing several rows of primordia root buds that feed the primary stem during its first month of life.
- Leaf scar. This is the residue of the yagua or leaf sheath.
Bud: Located in the root band, above the leaf scar. It may reach, touch, or extend beyond the growth ring. Its position on the stem is alternate and opposite. The most important part of the bud is the generative pore (Figure 3), which is the point where the shoot emerges upon germination.
It presents different forms (Figure 4).
The leaf and the yagua or sheath
Each internode has its corresponding leaf. Two parts are distinguished: the sheath or yagua and the leaf or leaf blade.
The sheet: It is the narrow, lanceolate blade attached to the yagua. It is distinguished by its length, width, arrangement, color, texture, and the serrations on its edges.
- Length: varies from 0.50 – 1.8 m.
- Width: varies from 5 – 10 cm.
- Arrangement: Erect, when they remain rigid, almost parallel to the stem. Erect, with a bent tip; open; bent, when they form a more or less wide arch; and drooping, when the arch is more or less closed.
- Color: The natural and common color is green. Some are reddish and others are striped.
- Texture: Some are thin, others thick; some are soft to the touch; others are leathery and succulent.
- Edges: The leaf has spines or teeth on its edges that point upwards and can be thin or thick.
- Midrib: can be white, yellow, reddish or dark purple.
The pod or yagua: The lower part of the leaf that hugs the stem, supports the lamina, and protects the young stem tissue. As it ages, it separates from the internode; in some varieties, it remains attached, while in others, it detaches, leaving a leaf scar. The color varies from light green to purple. It may be covered with a layer of mulberry.
with wax and often has a covering of hairs (fuzz) that can be sparse or dense. These hairs can be stiff or soft; short or long; yellow, white, or brown; and can be persistent or deciduous. The outer area where the yagua frond joins the leaf is called the neck, and the inner area is called the throat, where the ligule and auricles are located. The ligule, which is a very important organ in the throat, is the site where the sheath and leaf join (Figure 5). The auricles are two triangular globules that exist at the upper corners of the yagua fronds and their shape can vary (Figure 6).
In the agronomic characterization we have into account germination, production of tillering and flowering.
Germination
Sowing is done with seed from first- and second-cut seedbeds, between 8 and 9 months old. Germination is assessed 30-45 days after sowing at four points in the field and 10 m from the furrow, where the percentage of germinated buds relative to the total number of planted buds is calculated. Germination is graded as follows:
- Excellent: when it germinates between
60-70% of the yolks. - Acceptable: when it germinates between
40%-60% of the yolks. - Difficult: when less than 40% of the buds germinate.
Tillering
It refers to the plant's ability to produce stems. The average number of stems from five strains is calculated.
Flowering
The sugarcane inflorescence is a silky, spike-shaped panicle consisting of a main axis and joints where the spikelets are inserted, one in front of the other. The spikelets contain a hermaphrodite flower with three anthers (which produce pollen) and an ovary (with ovules awaiting fertilization) with two stigmas (which receive pollen during pollination).
Varieties are characterized by the percentage of stems with inflorescence. In the plot, at four randomly selected sites, the total number of stems per 10 meters and the number of flowering stems are counted. Thus, flowering can be:
- Null or scarce: between 0 – 10% of stems
bloomed. - Low: between 11 – 20%.
- Average: between 21 – 30%.
- High: between 31 – 49%.
- Very high: more than 50%
Diseases
The varieties are evaluated for their behavior against diseases that affect sugarcane in the Cauca River Valley:
- Ustilago scitaminea (Sydow) coal.
- Brown rust Puccinia melanocephala (H. Sydow and P. Sydow).
- Orange rust Puccinia kuehnii (Butl.).
- Sugarcane common mosquito virus, ScMV (Potyvirus).
- Yellow leaf virus, ScYLV (Polerovirus).
- Leaf scald Xanthomonas albilineans (Asby) (Dowson).
- Soca rickets Leifsonia xyli subsp. xyli (Davis et al., 1984) (Evtushenko et al., 2000).
Pest insects
The pests included in the assessments are:
- Stem borers Diatraea spp. (Lepidoptera: Crambidae).
- Yellow aphid Sipha flava (Homoptera: Aphididae).
- Spit of the cane Aeneolamia varies (Hemiptera: Cercopidae).
