POLLINATION CONTROL (SELF-INCOMPATIBILITY) (define (1) the inability of…
1) the inability of the fertile pollen to fertilize in the same flower.
2) This prevents self-fertilization but promotes cross-pollinations.
SI is one of the most important means of preventing inbreeding and promoting the generation of new genotypes in plants, and it is considered as one of the causes for the spread and success of angiosperms on the earth
In plants with SI, when a pollen grain produced in a plant reaches a stigma of the same plant or another plant with a similar genotype, the process of pollen germination, pollen-tube growth, ovule fertilization and embryo development is halted at one of its stages and consequently no seeds are produced.
the classification of SI
the relevance of SI
1.In self - incompatible fruit trees, it is necessary to plant two cross-compatible
varieties to ensure fruitfulness.
Further, cross-pollination may be poor in adverse weather conditions reducing fruit set.
Therefore, it would be desirable to develop self-fertile forms in such cases
2.Some breeding schemes, e.g., development of hybrid varieties etc., initially
require some degree of inbreeding
Although sibmating leads to inbreeding,
but for the same degree of inbreeding it take twice as much time as selfing
Further, for the maintenance of inbred lines selfing would be necessary.
3.Self-incompatibility may be used in hybrid seed production.
For this purpose,(1 ) two self-incompatible, but cross-compatible, lines are interplanted; seed obtained from both the lines would be hybrid seed.
(2) Alternatively, a selfincompatible line may be interplanted with a self-compatible line, from this
scheme, seed from only the self-incompatible line would be hybrid
(3) Schemes for the production of double cross and triple cross hybrids have also been proposed and their feasibility has been demonstrated in the case