Method for early detection of sex in papaya

The sex is revealed only after six to eight months when the plants start flowering which affects farmers who have to weed out excess of male plants as only five per cent male plants in a field are sufficient for pollination.

Scientists at the National Chemical Laboratory NCL here have developed a method based on quot;deoxyribonucleic acid DNA markersquot; by which sex of papaya plants can be determined at one or two-month seedling stage so that requisite number of male and female plants can be planted to maximise harvest.

By cultivating male and female plants in a desired ratio, use of planting space, fertilizer and water could be optimized, P K Ranjekar, head of division of biochemical sciences and plant molecular biology in NCL, told PTI.

The method has been developed by Ranjekar, Anjali Parasnis, a Phd student, and Vidya S Gupta.

DNA is isolated from the nucleus of papaya leaf cells and broken into pieces by using special kind of enzymes called quot;restriction enzymesquot; which digest DNA into fragments, Ranjekar said.

The DNA fragments are amplified using quot;polymerase chain reaction PCRquot; technique and then visualised by staining methods.

After amplification, a specific DNA fragment is seen in males which is absent in females that helps identify the sex of the plants.

The lab-scale method needed to be scaled up to be used by seed companies and papaya breeders, he said.

Earlier attempts to identify sex-specific differences in papaya by comparing biochemical constituents and external features had been unsuccessful.

Patents for the method have been filed in India and the united states, Ranjekar added.