Breeding of Vegetable, Spice and Tuber crops (2+1)

Heterosis,Polyploid and Mutation Breeding

Heterosis breeding

• To exploit the hybrid vigour in cassava, work done at CTCRI, Thiruvananthapuram revealed that some hybrids are performing better than their parents and even existing varieties in terms of tuber yield, quality etc.

Polyploid breeding

• Induced tetraploids by colchicine treatment was attempted at CTCRI, Thiruvananthapuram and found that they were poor yielding and less adapted to the normal field conditions.
• However,one of the triploid strains evolved after crossing tetraploids and diploids out-yielded both the parents and the scientists were of the opinion that there is a possibility of improving cassava by producing new chromosomal races in which the chromosome underdoes not go beyond an optimum level.
• Evolution of triploids by crossing diploids and the artificially induced tetraploids has been done.
• Though a few of the selected triploids showed relatively high dry matter content and extractable starch, they did not prove to be superior in yield to the released varieties namely Sree Visakham and Sree Sahya.
• A spontaneous triploid was identified from a cross involving the two released diploid varieties H-165 and Sree Sahya.

Mutation Breeding

• Mutation with gamma irradiation has been employed successfully on single node cutting of cassava but no economic mutant has been isolated so far.