Phenology. Growth stages :

      Phenology is the study of events of lifecycle in plants and influenced of physical actors like season , climate , soi , topography , etc.

                The entire lifecycle of rice plant can be divided into three main phases as 

Germination to emergence : 1^st leaf appears 3 DAS.

a) Vegetative phase : seed germination to panicle initiation , 60-70 DAS.

b) Reproductive phase : panicle initiation to flowering , 35 DAS.

c) Ripening phase : Flowering to full maturity , 30 DAS.

a) Vegetative phase (seed germination topanicle initiation ) 60-70 DAS

I) seedling stage :

• Leaf develops at the rate one per 3-4 days.
• Upto 5 leaf stage , the seedling becomes autotrophic.

ii) Transplating phase :

• Found only in transplanted rice but not in DSR.
• 20-25 days old seedling are ready for transplanting
• Transplanting shock upto 5-10 days for developement of secondary roots.

iii) Tillering stage :

• 35-40 DAS
• First tiller to maximum tillering stage
• upto tertiary tillers
• Some tiller dies and only effective tillers remains.

b) Reproductive phase (panicle initiation to flowering ) 35 days :

I) Panicle initiation stage : Flower premodium initiation at the tip of growing shoot.

ii) Bolting stage :

• Also known as stem elongation or internode elongation stage.
• Production of auxin accelerates growth of internodes.
• Panicle cause bulging in the leaf sheath.

iii) Heading stage :

• Also known as panicle energence stage .
• Panicle tip energes out of the flag leaf sheath.
• Occurs 15 days after booting.

iv) Flowering stage :

• occurs 25 days after booting and 5 days after heading
• Lodicules becomes turgid pushing lemma and palea apart , thus opens the flower (anthesis) out for pollination
• After pollination, lemma and palea are closed.
• Pollination is followed by fertilization.

c) Ripening phase (flowering to full maturity) , 25-30 DAS :

I) Milky stage :

• The content of caryopsis are first watery but later turns into white milky fluid which can be squeezed out.

ii) Dough stage :

• 2-3 week duration
• soft dough : 5-7 days
• hard dough : 5-7 days
• Greenish tint

iii) Maturity stage :

• Physiological maturity : max. dry matter accumulation in the seed , 80n % grains in panicle are matured.
• Harvesting maturity : Moisture content of seed is reduced , 90 % grains in panicle are matured .