SUNFLOWER (Helianthus
annus)
Ø Land Requirements
Select field in which sunflower was
not grown in the previous year unless they were of
same variety. In addition the
selected field should be well drained and the soil deep, fertile
and with neutral pH.
Ø Isolation Requirements
Sunflower is a cross pollinated
plant crop. The extent of cross pollination varies from 17-
62%, according to insect activity.
The seed field must be isolated at least by 400 m for
foundation seed and 200 m for certified seed
class from fields of other variety.
ü Cultural Practices
1. Preparation of land:- Usually
one deep ploughing, two to three harrowings followed by leveling are adequate
to prepare the field to the desired tilth.
2.
Time
of sowing:-Sunflower, unlike most other crops, are
not season bound. Sowing should be so adjusted that the maturity of the crop
does not coincide with the rains, since rains during maturity period adversely
affects the seed quality.
3.
Source
of seed:-Obtain nucleus / breeder’s / foundation seed from
the source approved by the seed certification agency.
4. Method of sowing:-The
crop should be sown in rows .The depth of seeding should be 2 to 4 cm.
5. Spacing:- Row to row 60cm.
Plant to plant 20cm.
6.
Seed
rate:-8 to 10 kg per hectare.
7.
Fertilization:-
The
fertilizer required for raising a good sunflower crop is 80kg nitrogen, 40kg
phosphorous and 40kg potash per hectare. At the time of
planting 50kg nitrogen and the full amounts of phosphorus and potash should be
applied as a basal dose and the
remaining 30kg nitrogen at the time of earthing
i.e., after 40 to 45 days of crop growth.
8.
Irrigation:-
Presowing
irrigation is necessary in the spring to summer season, and desirable for rabi
sowing for uniform germination and better stand. Sunflower is comparatively
drought tolerant and yields higher under moisture stress conditions.
In
rabi and zaid planting 2-4 irrigations respectively, are necessary for higher
yields. In Kharif, if rainfall distribution is favorable, no irrigation may be required.
One irrigation between the flowering and grain filling stages must be applied.
9.
Weeding
and Interculture:- One to two weedings during the first six
weeks after germination are necessary
10.
Earthling:-
The
sunflower plants may root lodge because of large heavy heads. Earthing,
preferably before and if needed, around 48 days after sowing is highly
desirable. 10 to 15 cm high earthing is sufficient.
Ø Supplementary Pollination:- Placing of bee-hives on the field periphery or on the
blank strips approximately at 200 m intervals has been found beneficial for
cross-pollination and seed set.
Ø Plant Protection:- Alternaria
blight may assume serious proportions in the rainy season and may reduce yield
drastically. The dark brown and black colored spots, if seen on any plant part,
should be immediately sprayed with 0.25% spray of dithane M-45 at one to two
weeks intervals. Other disease of
minor importance is: Sclerotium wilt in July and august plantings. The affected
plant should be uprooted and burnt.
Ø Roguing:- Generally
two roguings are needed. The first should be done at the preflowering stage and
the second at crop maturity. Precautions
in Roguing:-Sunflower head continues to develop and shed viable pollen even
after removal from stalk. It is therefore, important that the heads after
removal from stalks are turned down (face down on the soil) while throwing them
on ground.
Ø Harvesting and Threshing:-The
crop is ready for harvest when the top leaves are dry and flowers are
shriveled. Heads may be removed with knife. Heads after cutting are sun dried
on the threshing floor. Hand threshing can also be done by rubbing seed heads
on a metal sheet or beating with sticks. Threshed seed must be dried to 8-10%
moisture before storage.
Ø Seed Yield:-
A good crop may give an average yield of 15 qtl (1 qtl =100kg) per hectare.
PRODUCTION
OF HYBRID SUNFLOWER SEED
Hybrid sunflower
is produced by using cytoplasmic male sterility and genetic fertility
restoration system. The male sterile line (A line) contains sterile cytoplasm
and recessive genes for fertility restoration. This is maintained by a male fertile
counterpart (line B) which also contains recessive genes, but has fertile
cytoplasm.
For production of hybrid seed male
sterile line (A-line) is crossed with a fertility restoring line (R-line) which
has the dominant genes for fertility restoration.
Planting Ratio:-
The proportion of female line (A-line) and male line (R-line) should be 3:1.
However the first two border rows on either side may be sown with the male line
(R-line) seed to ensure enough pollen supply.
Seed
Rate:- A-line 7.5kg/ha
B-line 2.5Kh/ha
R-line 2.5Kg/ha
R-line 2.5Kg/ha
Roguing:-
The male fertile plants in the female parent lines should be removed each day
during the entire flowering period. This is the best done in morning hours
before the bees have removed the pollen
Supplementary
Pollination:- For supplementary pollination (hand
pollination) the palm is first gently rubbed on the male parent flowers and
then on the stigmas of the female line to transfer the pollen.
Harvesting:-
The male parent rows should be harvested prior to harvest of female rows to
avoid contamination. No male parent heads should be left intermingled with the
female parent rows.
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