Apomixis by sudha

Cyto genetics and plant breeding apomixis types advantages and disadvantages

1. Sudha's KSM 95

2. Dr . Balasaheb Konkan Krishi
Vidhyapeeth
COLLEGE OF AGRICULTURE
ACADEMIC YEAR 2017-18

COURSE INSTUCTOR:
Dr .Mrs. S.S. Desai

Sudha's KSM 95

3. Apomixis, Evolutionary and Apomixis, Evolutionary and
genetic problems in crop genetic problems in crop
with apomixiswith apomixis
By:
SUDHA MANI.K
ADPM/17/2555
Sudha's KSM 95

4. Actual process of sexual reproduction:
Sudha's KSM 95

5. Need for apomixis:
•To overcome some of the difficulties that plant face during
sexual reproduction. (sterility)
•Fixing of heterosis in F1 hybrid plants.
•Rapid production of Homozygous plants.
APOMIXIS IN CROPS:
•Identified in over 3000 species belonging to 30 families.
•Most frequently found in families like Compositae , Rosaceae
, Graminae , Asteraceae.
•Thus it is not rare but relatively uncommon.
Sudha's KSM 95

6. Sudha's KSM 95

7. Sudha's KSM 95

8. CLASSIFICATION OF
APOMIXIS
MODES OF REPRODUCTION
SEXUAL
ASEXUAL







adventitious embrony
apospory parthenogenesis
androgenesis apogamy

VEGETATIVE APOMIXIS
Gametophytic Sporophytic
Diplospory
PSEUDOGAMY
Sudha's KSM 95

9. Sudha's KSM 95

10. Sudha's KSM 95

11. Sudha's KSM 95

12. Sudha's KSM 95

13. DETECTION OF APOMIXIS:
•Failure to obtain F1 plants from a cross( female – apomictic).
Production of uniform progeny in F2 population.
•Uniform progeny from a heterozygous plant or from an open
pollinated sps. ( graminaceae )
•Production of maternal phenotype in the progeny from crosses
without selfing.
•Prod. Of maternal progeny with recessive gene even though it is
crossed with a male pollinator carrying dominant marker.
Sudha's KSM 95

14. •High seed rate or uniform progeny in plants with irregular
chromosomal number or meiotic behaviour.
•Multiple seedlings per seed, flowers with two or more fused
ovaries, multiple stigmas and multiple ovules per floret.
•In selfed generation, presence of plants showing no
inbreeding depression is indicative of apomixis.
•Embryological studies of young ovules confirm apomixis.
Sudha's KSM 95

15. GENETICS OF APOMIXIS:
•Failure of meiosis during megasporogenesis.
•Initiation of mitosis in the unfertilized (2n) egg cell or some other (2n)
cell of embryo sac.
Sudha's KSM 95

16. The ideal apomictic system:
1.All the progeny of plants should be apomictic.
2.Apomictic genotype should be fully male fertile and self
incompatible.
3.Chromosomes should not pair in first meiotic division in
case of diplospory.
4.Apomixis should be dominant over sexual reproduction.
5.Expression of apomixis should be little effected by the
environment.
Sudha's KSM 95

17. Development of Apomictic lines:
•Genes transfer from wild species.
•Induced mutations.
•Isolation of apomictic recombinants from Interspecific
crosses.
Sudha's KSM 95

18. ADVANTAGES OF APOMIXIS:
•Fixation of heterosis in the hybrids.
•Easy maintenance of purelines.
•Synchronous flowering and maturity of the crop.
•Nucleus seed of hybrid varieties is conveniently maintained
as the hybrid varieties.
•Minimal isolation distance in hybrid seed production.
•Pollen dispersal is not relevant during hybrid seed
production.
Sudha's KSM 95

19. PROBLEMS IN UTILIZATION OF
APOMIXIS:
•Apomixis is very complicated phenomenon.
•Estimation of the level of facultative apomixis is tedious and
time consuming.
•Facultative apomicts are affected by environmental factors
like daylength and temperature.
•In absence of morphological markers linked with apomictic
development, maintenance of apomictic stock becomes
difficult.
•The genetic basis of apomixis is not clear in most cases.
Sudha's KSM 95

20. FOR YOUR PRECIOUS TIME
Sudha's KSM 95