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WELCOME
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“ Seed Maturation in Mustard ”
Submitted to , Dr. G. U. Kulkarni.
Asst. professorDept. of Genetics and Plant Breeding
JAU, Junagadh.
Submitted by , Indu
( M.Sc. Agri.) Reg. no. J4-01148-2013
Dept. of Genetics and Plant BreedingJAU, Junagadh
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CONTENT :-1. Introduction.2. Floral biology.3. Pollination.4. Fertilization.5. Seed Maturation.6. Determination of seed
Maturity.
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1.INTRODUCTION
Family : Cruciferae
Botanical name : Brassica sp.
Chromosome no. : 2n = 16, 18, 20, 32, 36, 38
Origin : Central Asia, India, china
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Crop name Species Name Common name
Chr. No. (2n)
Use
Mustard Brassica nigra Black mustard
16 Condiment
Mustard Brassica oleracea Kale 18 Vegetable
Turnip rape Brassica compestris Yellow mustard
20 Vegetable
Rai Brassica juncea Indian mustard
36 Vegetable, oil seed
Table no. 1. Genus Brassica and their Ecotype
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India is the fourth largest oilseed economy in the world. Among the seven edible oilseeds cultivated in India, rapeseed-mustard contributes 28.6% in the total oilseeds production and ranks second after groundnut sharing 27.8% in the India’s oilseed economy.
Indian mustard (Brassica juncea (L.) Czernj. & Cosson) is predominantly cultivated in Rajasthan, UP, Haryana, Madhya Pradesh, and Gujarat.
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Fig. no.1 Morphological structure of Mustard crop plant
Leaf
stem
Flowerpods
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2. FLORAL BIOLOGY
Flower is regular , bisexual and hypogynous with four free sepals into whorls.
Typical flower formula :-
K2+2,C4,A2+4,G(2)
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Cont….
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Reproductive floral organs: female• Carpel or pistil – (female reproductive organs) contains:
• Stigma – is where pollen sticks .
• Style – is the long tube that connects stigma to ovary.
• Ovary – enlarged structure at the base of carpel/pistil where the ovules are located; it will become the fruit.
• Ovules – contains female gametophyte, becomes the seed.
Cont..
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Reproductive floral organs: male• Stamen – male floral organ, consists of:• Anther – part of the stamen that produces pollen• Filament – stalk-like structure that holds anther• Pollen – immature male gametophyte
Cont..
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3. POLLINATION
• Pollination : The transfer of pollen from the male anther to the female stigma
• The infloresence is racemose and flowering is inderminate, beginning a the lowest bud on the main raceme.
• The flower opens early in the morning and are fully opened by 8 to 9 a.m.
• The flowering period may last for 2 to 3 weeks.• The stigma receptive for 3 days after opening of
flower (Mohammad, 1935).• As soon as the flower opens , the anther become
extrose and dehisce when the petals completely shed.
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Cont..
• All the pollen shed on the day flowers open , provided the dry weather occurs.
• The flower forms a funnel shaped structure during evening.
• The pollen can stored for 4 to 5weeks without the loss of variability
• The pollen analysis of different Brassica sps. indicate that fertilization is affected within 24 hrs after pollination .
• The syncarpous ovary develops into pod ( Siliqua) with two carpel by a false septum.
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Cont…
4. FERTILISATION
DOUBLE FERTILIZATION :-
• A process in the flowering plant life cycle in which there are two fertilizations
• One results in formation of a zygote .
• Second results in formation of endosperm.
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5.SEED MATURATION
Delouche (1971) :
Seed maturation is a process that comprises a set of morphological, physical, physiological and biochemical events that occur from ovule fertilization to the moment in which seeds become physiologically independent of the parent plant. 16
• The maturation process takes place in the fruit on the parent plant.
•Endospermous seeds: Retain the endosperm tissue, which eventually dies but it is surrounded by a layer of living cells, the aleurone layer.
•Non-endospermous seeds: The endosperm tissue is absorbed by the cotyledons. These then become the food reserve for the seed.
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Cont..
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Cont…
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•The pollinations had, as a rule succeeded, though the number of fertilized ovules in the siliqua varied.
•The initial development of the seeds was normal. 1st day after pollination there could be two or four endosperm nuclei, and after 3rd days a proembryo was sometimes formed.
• In the endosperm 32 nuclei were counted, four of them near the chalaza . The siliqua, fixed 6th days after pollination, were unfortunately in a rather poor condition, only a few good ovules being found.
• An embryo globe counting 16 cells was observed.
•The endosperm was fairly normal, though the apical and basal endosperms were as a rule under-developed.
Cont…
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•A slow development was evident after 10 days. The young seeds were comparatively small with some starch in the inner layers of the inner integument.
•The embryo was always a globe of varying size, for instance, with 10-15 cells along the diameter; it never, however, had attained the heart stage. The endosperm was weak, a cytoplasm with nuclei being near the wall of the cavity in the ovule.
•The basal endosperm contained little cytoplasm and few nuclei; some nuclei could be large.
•Most ovules had no apical endosperm. However, a few siliqua had better ovules with an endosperm of more normal size and differentiation. After 14 days such vigorous seeds were larger and had more starch.
Cont…
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•After 21 days the better seeds had an embryo approaching the torpedo stage; the endosperm consisted of a sometimes considerable endosperm with free nuclei, a number of the latter being enlarged.
• After 28 days the best seeds also were very small, but an embryo may be present; this consisted of a larger globe or had small cotyledons.
• Endosperm is often absent.
Cont…
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• Term Explanation in detail
• Reticulate - Having a raised network of narrow and sharply angled line frequently presenting a geometric appearance, each area outlined by a reticulum being an interspace.
• Foveate - Pitted or having depressions marked with small pits.
• Reticulate-foveate - A type intermediate between reticulate and foveate types .
Seed Coat Microscuplturing Changes in Brassica
Cont…
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• Rugose - Wrinkled irregular elevations folding mostly running in one direction.
• Rugose-foveate - A type intermediate between rugose and foveate types.
• Ruminate - Penetrated by irregular channels giving an eroded appearance and running in different directions.
• Blister - Having a expansible convex and frequently presenting a 5-6 sided appearance, each area outlined by a line or curve being an Interspace
• Reticulate-blister - A type intermediate between reticulate and blister types
Cont…
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FIG. 2. Different types of seed coat microsculpturing in Brassica observed by scanning electron microscope at low magnification. Rugose in(A) B. oleracea (5 DAP), (B) B. nigra (10 DAP), and (C) B. nigra (15 DAP ). Blister in (D) B. napus 1256 (15 DAP), (E) B. nigra (20 DAP) and(F) B. carinata (20 DAP). Foveate in (G) B. nigra (mature dry seed), (H) B. juncea (20 DAP) and (I) B juncea (20 DAP). Reticulate in(J) B. juncea (mature dry seed), (K) B. rapa (mature dry seed) and (L) B. oleracea (35 DAP).
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• As brassica seed develops a rapid increase in fresh mass is observed concomitant with increase in dry mass.
• In rape seed reserve mainly occur in the form of Oil ( 75 % of total dry weight) and Protein ( 20 % of total dry weight).
• Protein is the major seed reserve utilize after radical emergence .
Cont…
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• Absicisic acid is require for normal seed development and apparently has a role in desiccation tolerance and stimulating storage reserve accumulation.
• ABA accumulates during the dry matter accumulate phase and decline as the water content of seed drops.
• The seed enters the post abscission phase during which time further physiological development.
Cont…
a) Seed maturity is identified by the maximum dry matter accumulation.
b) Seed physiological maturity is reached when there are no significant increases in seed dry weight.
c) Seed physical maturity occurs when seeds reaches maximum dry weight, particular change in colour of seed coat, and vigor.
6. DETERMINATION OF SEED MATURITY :-
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