self incompatibility and male sterility

crop improvement

1. Presentation on:- SELF INCOMPATIBILITY & MALE STERILITY -Its classification and use in crop improvement. Submitted to:- Dr. K. P. Singh (Course Teacher) HPB-311 Breeding of Vegetables, Tubers and Spices SUBMITTED TO:- Ms. Ishita Dey B.Sc (Hort) 3 rd Year/ 1 st Sem CHRS, Jagdalpur

2. SELF INCOMPATIBILITY Term coined by “Stout” in 1917. “It refers to the inability of a plant with functional pollen to set seeds when self pollinated.” First reported by “ Koelreuter ” in Verbascum phoenicum plants in 18 th century. It maintains high degree of heterozygosity and can take place at any stage between pollination and fertilization.

3. Continued.. It prevents autogamy and promotes allogamy . Self incompatible species do not produce seed on self pollination but lead to normal seed set on cross pollination. It results due to morphological, genetic, physiological and biochemical causes.

4. Classification:- On the basis of flower morphology Heteromorphic : Self Incompatibility is associated with difference in flower morphology. Distyly Tristyly Styles and stamens Styles and stamens are of 2 types i.e. have 3 positions i.e. Short and long. Short, medium and long.

5. Distyly example:-

6. Tristyly example:-

7. Classification contd.. (B) Homomorphic : The flowers do not differ in morphology. Gametophytic Sporophytic Self incomatibility Self incompatabilty is governed by geno - is governed by the -type of pollen genetic constitution producing plants. of gametes. Ex: Potato, Tomato Ex: Cabbage, Radish

8. Classification contd.. On the basis of genes involved Monoallelic Diallelic Polyallelic Governed by Governed by Governed by one gene. two genes . several genes.

9. Classification contd.. On the basis of site of expression Stigmatic Ovarian Stylar Genes express Genes express Genes express on stigma. in ovary. in style.

10. Classification contd.. On the basis of pollen cytology Binucleate Trinucleate Pollen grains have Pollen grains have two nuclei. three nuclei.

11. Use in crop improvement: Hybrid seed production without emasculation and without resorting to genetic or cytoplasmic male sterility. Ex- Cabbage and Brussels sprout. For commercial seed production in some cruciferous crops. Ex- Cauliflower. Permits combining of desirable genes in a single genotype from two or more different sources through natural cross pollination which is not possible in self compatible species.

12. Male sterility:- First reported in flowering plants by Koelreuter in 1763. “It refers to a condition in which pollen is either absent or non-functional in flowering plants.” It prevents autogamy and promotes allogamy . Male sterile plants produce seeds only on cross pollination with functional pollen of other plants.

13. Continued:- It results from the actions of nuclear genes or cytoplasmic genes or both. It is caused due to pollen or anther abortion. It occurs in nature through spontaneous mutation as well as can be induced artificially by chemical or physical mutagens.

14. CLASSIFICATION:- Genetic Male Sterility (GMS) Pollen sterility caused by nuclear genes. Reported in tomato, cucurbits and sugarbeet . Male sterility genes are usually recessive and rarely dominant. In most cases, sterility is caused by single gene, but in some two or more genes control male sterility.

15. CLASSIFICATION CONTD. Consists of two types of lines: 1) A line- male sterile line(mm), used as female parent in hybrid seed production. 2) B line- heterozygous fertile line(Mm), used to maintain sterile line.

16. Merits & demerits: Used for production of hybrid seed in both seed and vegetative propagated species. Requires less area and labour . Less stable as it becomes fertile at low temperature. 50% plants are fertile which have to be removed every year which increases the cost of hybrid seed.

17. Classification contd. Cytoplasmic Male Sterility (CMS) Pollen sterility controlled by cytoplasmic genes or plasmages . Reported in potato, forage crops etc. Plants carrying particular types of cytoplasm are male sterile but will produce seeds if pollinators are present. The F 1 seeds produce only male sterile plants, because their cytoplasm is derived entirely from the female gamete.

18. Classification contd. This system consists of A line and B line, which are male sterile and male fertile respectively. The cytoplasmic male sterile line is maintained by crossing of A line with B line. Used for development of hybrids in vegetatively propagated plants due to absence of restorer line.

19. Merits & demerits: Highly stable and is not influenced by environmental conditions like temperature and day length. Requires less area. Cannot be used for development of hybrids in those crops where seed is the economic product. Used only in asexually propagated species.

20. Classification contd. Cytoplasmic Genetic Male Sterility (CGMS) Pollen sterility is controlled by both cytoplasmic and nuclear genes. First discovered by Jones and Davis in 1944 in onion. It includes A, B, and R line, which are male sterile, male fertile and restorer line respectively. R line restores fertility in the F 1 hybrid.

21. Classification contd. Cytoplasmic male sterile line is maintained by crossing the male sterile cytoplasmic line with male fertile cytoplasmic line.

22. Merits & demerits: Widely used for hybrid seed production in both seed and vegetatively propagated species. Highly stable and reliable. Not affected by environmental factors. It requires more area and labour . Sometimes CGMS line have inferior agronomic performance.

23. OTHER TYPES: Chemically Induced Male Sterility Chemicals are used for induction of male sterility which are called Male gametocides . Ex- NAA, MH, Gibberellins . Transgenic Male Sterility Foreign genes from micro-organisms by the technique of genetic engineering is used for the induction of male sterility. Ex- B acillus amyloliquefaciens in tobacco and rapeseed.

24. Use in crop improvement:- Genetic male sterility can be used for the development of commercial hybrids in both seed and vegetatively propagated species. Ex-Tomato, Watermelon etc. Cytoplasmic male sterility is useful for the development of hybrids of ornamental plants. Ex- Rose, Marigold. Cytoplasmic genetic male sterility has been effectively used for the commercial production of hybrids in Onion, Sugarbeet , Tomato, Sunflower.

25. Thank you for your kind attention.