(a) (i) State the objective of adopting artificial hybridisation programme in plants. (ii) Describe the steps followed in this technique.

To combine desirable characters from two different varieties , so as to

obtain improved/ superior variety

If the female parent plant bears bisexual flowers, it is necessary to

remove the anthers from the flower before its dehiscence. which is called emasculation , such flowers are then bagged , (with butter paper bags of suitable size) to prevent contamination of its stigma. which is called bagging

, When the stigma of bagged flower attains receptivity, mature pollen collected from anthers of the male parent are dusted on the stigma , and flower is rebagged and fruit is allowed to develop.

After implantation, finger-like projections appear on the trophoblast

called chorionic villi , which are surrounded by uterine tissue and maternal blood , The chorionic villi and uterine tissue become interdigitated with each other , and jointly form a structural and functional unit between developing embryo and maternal body called placenta.

Placenta facilitates supply of O2 and nutrition to the embryo , and

removal of CO2 and waste from foetus , Placenta also acts as endocrine tissue and produces several hormones hCG hPL estrogen progesterogen essential for maintaining pregnancy.