Seed development and maturation

1. Seed Development &
Maturation
Department of Seed Science & Technology
TAMIL NADU AGRICULTURAL UNVIVERSITY
Coimbatore – 641 003
Department of Seed Science & Technology, TNAU, Coimbatore

2. Department of Seed Science & Technology, TNAU, Coimbatore

3. Stages of Seed Development
 Formation of stamens and pistils
 Megasporogenesis & Megagametogenesis
 Microsporogenisis & Microgemetogenesis
 Pollination
 Fertilization
 Embryogenesis
Department of Seed Science & Technology, TNAU, Coimbatore

4. Megasporogenesis Megagametogenesis
Step 1. Formation
of megaspore
Step 2. Development
of embryo sac
Department of Seed Science & Technology, TNAU, Coimbatore

5. Microsporogenesis Microgametogenesis
Step 1. Formation
of microspores
(or) pollen
mother cell
Step 2. Development
of pollen grain
Department of Seed Science & Technology, TNAU, Coimbatore

6. Structure of a flower
Megagametogenesis
Microgametogenesis
Department of Seed Science & Technology, TNAU, Coimbatore

7. Pollination
Department of Seed Science & Technology, TNAU, Coimbatore

8. Types of Pollination
• Rice, black gram, green gram,
• Closer Isolation DistanceSelf
• Maize, Bajra, Bhendi
• Wider Isolation DistanceCross
• Cotton, Red gram
• Wider Isolation DistanceOCS

9. POLLEN MANAGEMENT through foliar spray
 Boron spray
@ 345 g ha-1
(i) Better pollen viability
(ii)Higher pollen germination
iii) Proper growth of pollen tube

10. Fertilization
Department of Seed Science & Technology, TNAU, Coimbatore

11. Embryogeny and storage tissue formation
Department of Seed Science & Technology, TNAU, Coimbatore

12. Effect of foreign pollen on seed production
 Maize
 Effect of foreign pollen
on endosperm of seeds
 Sometimes Ridge Gourd
may taste bitter due to
pollination from bitter
gourd.

13. Deposition of reserves in storage tissues
a.Starch synthesis
b.Fat synthesis
c.Protein synthesis
d.Hormones in developing seed
Department of Seed Science & Technology, TNAU, Coimbatore

14. STARCH SYNTHESIS
 SUCROSE, the sugar
translocated mother plant to
the seed,
 It is converted into AMYLOSE
and AMYLOPECTIN
 Stored in AMYLOPLAST
Department of Seed Science & Technology, TNAU, Coimbatore

15. FAT SYNTHESIS
 SUCROSE translocated to
developing seed
 It is converted into
TRIBLYCERIDE (Fat)
 Stored in LIPID BODIES
Department of Seed Science & Technology, TNAU, Coimbatore

16. PROTEIN SYNTHESIS
 The code for protein synthesis
is present in DNA.
 r RNA, t RNA and m RNA are
involved in synthesis of
proteins in rough ER.
 It is stored in protein bodies.
Department of Seed Science & Technology, TNAU, Coimbatore

17. HORMONE SYNTHESIS
 Auxins, GA, cytokinin and ABA
 All hormones – except ABA- levels
are high during developing stage
 ABA level increases at maturity.
Department of Seed Science & Technology, TNAU, Coimbatore

19. • Supply of nutrition to mother plants
• It is important to supply the nutrients
required for all the above morphological &
synthetic processes
• It helps to increase number of flowers,
number of seeds, 100 seed weight of seeds
& crop yield

20. Benefits
• Two foliar sprays before and
after flowering
• Higher 100 seed weight
• Higher seed yield
• Better resultant seed quality
• Effective across all crops

21. Study in
Black gram

27.  Seeds do not imbibe water due to hard seed coat
 Do not germinate
 Seeds maturing during high temperature or drought express more hard seeds
Development of Hard seeds

28.  ….defined as the point of MAXIMUM DRY WEIGHT of
seed.
 ...at this stage, the VIABILITY AND VIGOUR of seeds are
also higher.
 Physiological maturity
 Harvestable maturity
Seed maturity
Department of Seed Science & Technology, TNAU, Coimbatore

29. Crop species Physiological maturity
(Days after anthesis)
Rice 30-35 days
Maize 30-35 days
Black gram 30 days
Red gram 35 days
Ground nut 50 days
Cotton 40 days
Bhendi 30-35 days
Physiological & Harvestable Maturity
Department of Seed Science & Technology, TNAU, Coimbatore

30. Crop Symptoms of maturity
Paddy Change of green colour to straw yellow colour panicle
Sorghum Formation of dunken layer (Black), change of earhead colour to pale yellow
(depending upon the variety)
Cumbu Formation of dunken layer (Black), Earhead colour changes to Ivary
Maize Husk dries and become straw yellow. Drying of silk
Cotton Hairline crack in Bolls
Sunflower Back side of thalamus turning lemon yellow in colour
Groundnut i) Black colouration in inner side of the shells
ii) Rattling sound of kernel
iii) Yellowing of older leaves
Pulses Turning of pod colour to Brown / Black
Soybean Withering of leaves. Pod colour change to brown
Gingelly Browning / yellowing of pods. Bottom 1 or 2 pods may have dehisced. Seeds become
chocolate brown in colour

31. Problems with early / late harvest
• Immature seeds
• Poor storageEarly
• Seed deterioration
• Preharvest sproutingLate

32.  Proper nutrition & irrigation in critical stages
 Harvest the seeds in maturity stage.
 Retain highest viability and vigour
 Records better storage potential
Points to remember…..
Department of Seed Science & Technology, TNAU, Coimbatore

33. Department of Seed Science & Technology, TNAU, Coimbatore