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1. DEEP WATER RICE
2019031027

2. Rice eco-system
Irrigated rainfed coastal saline cold/hills
Upland lowland
Shallow water semi-deep water deep water
(0<50 cms) (50-100cms) (>100cms)

3. Introduction
Common rice (Oryza sativa L.) cultivars are
generally planted in dry or irrigated areas, and are
comparatively tolerant to water compared to other
crop plants, such as
maize and wheat.
However, rice does not have complete tolerance
to flooding, and if it is completely submerged or
flooded for long periods,
Plants die due to oxygen starvation and energy
depletion development in roots.

4. • The Indica cultivar is the main type of
deepwater rice, although varieties of Japonica
have been found in Burma, Bangladesh and
India
• But deep water rice can able to withstand
water almost 50-100cm or even higher.
• The duration of the crops varies fro 150 to 240
days depend on the varieties.

5. Sowing season
• Deepwater rice is usually seeded dry in the
field during March-April following the first
monsoon shower.
• In some areas farmers establish deepwater rice
by transplanting of seedlings following dry
season rice. Until the onset of flooding in
June/July, the crop depends on rain.

6. Inter cultural operation
• Very little fertiliser is used and weeds are
controlled by harrowing and hand weeding,
twice before flood.

7. • Depending upon the cultivars, the plant
population usually reaches to the highest level
of 200-400 stems per sq m at the maximum
tillering stage in the pre-flood period.
• During flooding period, some stems may be
damaged by submergence and pest attack.

8. Yield
• Average grain yields are 2.3 mtons/ha and
some cultivars have the potential of producing
yields more than 3.0 m tons/ha

9. Maturity
• Crop matures between mid-October and mid-
December, depending on the degree of
photoperiod sensitivity of the cultivar.

10. • Deepwater rice grows under rainfed dry land
conditions for 2-4 months before the onset of
flood, when plant produces basal tillers.
• With inundation, the plant becomes an
emergent macrophyte and grows in an aquatic
environment for the remaining 3-5 months of
its life.
• Nodal roots absorb nitrogen, phosphorous
and possibly other nutrients from floodwater.

11. Areas
• In South Asia, the main area deepwater rice is
grown in is the Ganges Brahmaputra basin in
India and Bangladesh.
• In Southeast Asia, the main areas of
cultivation are in Burma in the Irrawaddy
Delta, in Thailand in the Chao Phraya and
Mekong in Vietnam and Cambodia.

12. Flooding conditions vary from submergence
of 1 to 10 days to stagnant water of varying
depth for up to 6 months.

13. contributions
• Rainfed lowland and flood-prone areas
constitute 35% of the total rice area, covering
47 million ha in Asia but providing only 25% of
global rice production because of various
abiotic challenges associated with rainfed
ecosystems (International Rice Research
Institute, 1997)

14. adaptation

15. • Deepwater (floating) rice has three special
adaptations: (i) ability to elongate with the
rise of water levels;
• (ii) develop nodal tillers and roots from the
upper nodes in the water; and
• (iii) the upward bending of the terminal part
of the plant called ‘kneeing’ that keeps the
reproductive parts above the water as the
flood subsides.

16. varieties
• Vast rice-growing regions in India, Bangladesh, and
other countries, which are submerged during rainy
season and rendered useless for rice production,
have been made productive since the SUB1 gene
that makes rice flood-tolerant was discovered and
bred into popular existing rice varieties.
• This variety has been very popular, with 1.7 million
hectares of land in India having Swarna Sub1 and
other flood-resistant varieties used instead of
conventional rice crops(International Rice Research
Institute, 2013c). Jalmgna, jalanidhi, jalapriya and
Hangeswarivarities are suitable for deepwater rice
areas

17. Sudha
• Sudha, the popular name given TCA72
(IET8977), has been released for rice areas
with up to 100 cm water depth in Bihar.
• It can be direct seeded in deepwater areas in
Mar or transplanted or direct seeded in May-
Jun in rainfed lowland waterlogged areas (25-
50 cm).

19. • Sudha was selected for its non-shattering
grain type and resistance to tungro and sheath
rot. It has drought tolerance at vegetative and
reproductive stages..
• It is 150-200 cm tall, depending on water
depth

20. Swarna
• A recent cultivar named Swarna Sub1 was
developed via marker-assisted selection, with
the ability to withstand prolonged periods of
around 14 days beneath a flooded plain.
• The submergence tolerance ability of this
variety is conferred by the presence of the
Sub1A gene, introgressed from the Indian
cultivar FR13A into the flood-vulnerable (but
high yielding) cultivar Swarna.

22. how to overcome problem
• To contain the water stagnation problem
under this ecology, varieties should have some
suitable features, such as height of 115-
130cm, stiff culm, erect leaves, drought
tolerance at seedling stage, submergence with
less elongation and without culm elongation
and strong seed dormancy

23. Rice growth adopting to deepwater :
1. The ‘escape strategy’ for deepwater
flooding.
• Rice plants tolerant to deepwaterflooding, where
water depth is from 50 cm to around 4 m, show
significant stem elongation as water levels rise.
• ‘escape strategy’ allows rice plants to access the
atmosphere, exchange gases in respiration, and
restart photosynthesis; however, this strategy
needs massive amounts of energy

24. ‘quiescent strategy’
• This involves stunted growth under complete
submergence and saves energy, allowing
regrowth after flooding; however, if flooding is
prolonged, the plants will die from
carbohydrate and energy deficiency.
• Rice independently adapted and evolved
these two contrasting strategies in response
to local environmental conditions

25. Advantages
• Deepwater rice emits the least methane, a
greenhouse gas, of the wetland rice ecologies,
producing approximately three times less than
paddy field rice.

26. • Deepwater rice is one of the world’s most
interesting and challenging crops.
• Rice is the only crop plant adapted to aquatic
environments because of its well-developed
aerenchyma tissues that facilitate oxygen
diffusion through continuous air spaces from
shoot to root and avoid anoxia

27. Dis advantages
Sudden flash flood may cause
moderate to complete damage of
rice plant population at onset of
rain.

28.  Flood prone rice faces severe weed growth. In
early stage, annual and perennial and at later
stage, perennial and floating type wild rice
weeds cause high yield reduction especially in
fields having low rice plant population

29.  Varietal improvement has very meagre scope in
flood prone rice. Only tall or elongating type varieties
are bred which have low yield potential. Unfortunately,
due to harsh ecology having low return, high yielding
variety (HYV) has not been evolved for flood prone rice
ecosystem.

30. Due to poor yield there is little economic
feasibility of scientific weeding, plant protection,
fertilizer use and harvesting, moreover, under
highly submerged conditions
(>100 cm) there is also problems in agricultural
operations.

31.  Deepwater rice does not normally survive at
water depths greater than 4 m

32. References
• Principles and practices of agronomy
by P. Balasubramaniyan and
P.Palamiappam.
www.reesarchgate.com
https://icar.org.in
https://agris.fao.org.

33. •Thank you