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1. METHODS TO OVERCOME INCOMPATIBILITY : There several methods to overcome incompatibility. They are, Mixed population, Bud pollination, Stub pollination, and Intra-ovarian pollination.

2. MIXED POLLINATION : In this method, the stigma is disguised from recognizing the incompatible pollen by pollinating it with a mixture of live incompatible pollen, and killed(by chemical or radiation) compatible pollen(termed Mentor pollen or Recognition pollen). By employing recognisition pollens, self incompatibility has overcome in Cosmos (Howlett et al.,1975) and Petunia hybrida (Sastri and Shivanna.,1975) and interspecific incompability in genus Populous(Knox et al.,1972).

3. BUD-POLLINATION : In some plants, pollination at an early bud stage has proceed very effective in overcoming intraspecific incompatibility. At the bud stage (before anthesis), the stigma lacks the exudate to inhibit pollens and by chance pollination at that stage may effect fertilization.

4. STUB-POLLINATION : In some plants incompability may be restricted to the stigma or the style is too long and the pollen tube could not reach the ovary. In this case, removal of stigma and part of style before pollination may prove helpful in overcoming incompatibility.

5. INTRA-OVARIAN POLLINATION : In this technique, the ovary surface is sterilized with ethanol and two punctures are made in the wall- one for introducing the pollen suspension and the other to permit the escape of of air in the ovarian cavity( Kanta et al.,1962). Variable seeds following intra-ovarian pollination have obtained in several members of Papaveraceae such as Argemone mexicana, A. ochroleuca, Papaver somniferous and P. rhoeas.

6. 1. HEAT TREATMENT OF STYLE : Moderately high temperature (up to 50 C) are known to reduce the self-incompability reaction in certain plants. e.g. Lilium longiflorum (Hooper et al 1967). 2. IRRADICATION : Induce temporary breakdown of incompatibility reaction (Pandey, 1963), or alteration of the inhibitory substances in the style(Kumar and Hecht,1965). Irradication helpful in those systems where process are controlled gametophytically.

7. 3. CHEMICAL TREATMENT : Application of certain chemicals may prolonged the life of flowers (Choudhury 1965). Oenothera species by the application of p- chloromercuribenzoate . Hodgdon and Hetch(1975 ). 4. PARASEXUAL HYBRIDISATION : In 1969 a new approach was proposed to raised such hybrid which could not be produced through the conventional method of hybridization because of sexual incompatibility. This technique involves fusion of isolated protoplast of somatic cell and is described as parasexual hybridization. This involves the following step :- (a)Isolation of protoplasts. (b)Fusion of isolated protoplasts. (c)Cultured of hybrid protoplasts to regenerate whole plant.

8. TECHNIQUES FOR OVERCOMING POST-FERTILIZATION BARRIERS A range of in vitro methods have been developed to overcome post-fertilization barriers in a number of plant species. When abortion occurs in a very young stage and maternal tissue has no negative influence on the development of seeds, ovary culture can be applied: young fruits can be grown in vitro to a stage at which dissection of embryos is possible. In some crops, the ovary is large and slicing the ovary in small parts and influencing them, is a better option for rescuing theb young seedlings in vitro.

9. Cntd… This technique is referred to as ’ovary slice culture’. When the mismatch between embryo and endosperm development starts very early and ovary culture and/or ovary slice culture fails, ovules can be dissected out of the ovaries and be cultured in vitro. If young fruits7 can stay for a longer time on the mother plant, embryo rescue can be applied by different methods: in ovulo rescue and embryo rescue. Since Hännig (1904) employed embryo culture for the first time 90 years ago, these techniques are applied in numerous crops (Williams et al. 1987).