Timing| FINAL TOPDRESSING at Panicle Initiation| Via GREEN RING start of Reproductive Stage

What is the green ring stage in rice?
Rice enters its reproductive growth phase at the panicle initiation stage. The panicle is now appears just as a green ring. The green ring stage is another name for the panicle initiation stage of rice because of this very reason. Internodes emerge right above the top node as green rings and are only visible for a few days.
It is important to start checking for sheath blight, a rice disease of global significance, right from the panicle initiation growth stage.
If the index values deviate from the expected range for the current stage of rice growth and development, it may indicate potential issues in the paddy, including crop diseases.
The most common conditions for sheath blight growth are nitrogen over fertilization, temperatures of 82-90°F (28-32°C), and rice canopy relative humidity of 85-100%. During rainy periods, plants are more likely to suffer from the disease. Thus, it’s crucial to keep an eye on variables like air temperature and precipitation in addition to the field’s vegetation cover. At times when the growth disease is the most likely, farmers should designate a scout to do regular spot checks on rice crops.
Stem Elongation
At this growth stage, the rice plant starts growing in height thanks to the elongation of its main stem, comprised of nodes and internodes. The variety of rice determines the ultimate stem height. In particular, late-maturing varieties tend to be taller than early-maturing ones. The following processes occur during the stem elongation stage of rice growth.
Internode Elongation
Beginning approximately seven days before the anticipated panicle differentiation, the internode elongation stage or rice growth continues until the plant reaches its maximum height, and then heading occurs. Stem internodes, as opposed to root ones, have a green tint to their walls.
Panicle initiation and internode elongation stages of rice growth, when the crop canopy and the vast near-surface roots work together decreasing fertilizer volatilization and maximizing nutrient absorption, are optimal stages for midseason N-fertilization
In tall varieties, the internode length can range from 2 inches (5 cm) at the base to 15 inches (38 cm) at the top, whereas in semidwarf varieties, it can range from 1 inch (2.5 cm) to 10 inches (25 cm). These values may differ depending on planting date, soil condition, flood depth, plant density, weed competition, and other factors.
The majority of rice varieties currently being cultivated have a consistent number of internodes (5-6) above the main stem’s crown. Once stem internode elongation starts, the main shoot can only produce a maximum of six new full leaves (one per internode). The topmost leaf on a fully grown rice stem, known as the flag leaf, is the last to develop. The results of photosynthesis it provides are mostly responsible for the development of grains, which is why this leaf is highly esteemed.
When the growth of internodes above the crown starts, root extension reaches its climax. Now, the secondary root system has strongly branched out in every direction below the crown. It is also a period that indicates the beginning of the reproductive stages in rice.
Panicle Differentiation
The process of panicle differentiation in rice happens while the internode and panicle growth is ongoing. It’s now when the newly developed panicle becomes visible for the first time. The panicle has reached a length of around 0.12 inches (3 mm) and continues its growth within the stem.
In terms of management, the panicle length is the defining characteristic of this rice development stage. Fungicide labels often suggest applying the product “from a 2- to 4-inch panicle” (5- to 10-cm). When the panicle reaches around 4 inches (10 cm), you can discern individual florets on its most mature branches.
Apply herbicides, including 2,4-dichlorophenoxyacetic acid and propanil, to rice before the panicle differentiation stage to avoid harming the plant.
Booting
During the booting stage of rice growth, the many components of a panicle mature within the protective sheath of the flag leaf. This sheath represents the boot. Three distinct stages of rice booting are defined by how much of the flag leaf sheath is visible above the penultimate leaf’s collar:
Early boot. Starts from the moment a flag leaf’s collar is visible until it’s around 2 inches (5 cm) above the collar of the preceding leaf.
Middle boot. The flag leaf’s collar shows up 2-5 inches (5-13 cm) above the preceding leaf’s collar.
Late boot. The flag leaf’s collar shows up for a minimum of 5 inches (13 cm). As there’s an active growth of panicles by now, the boot swells, earning the name “swollen boot” for this growth stage. Environmental stresses on rice may now diminish grain yields.
✓ During the booting stage of rice growth, apply propiconazole or other triazole fungicides to protect the rice crop from kernel and false smut