Question

Hybrid vigour is due to

• A. Chiasma
• B. Linkage
• C. Crossing over
• D. Heterozygosity

Answer 1

The correct option is D Heterozygosity

Heterosis is also called as hybrid vigour. It is the increase in such characteristics as size, growth rate, fertility and yield of a hybrid organism over those of its parents. Plant and animal breeders exploit heterosis by mating two different pure-bred lines that have certain desirable traits. The first-generation offspring generally show, in greater measure, the desired characteristics of both parents. This vigour may decrease, however, if the hybrids are mated together. So the parental lines must be maintained and crossed for each new crop or group desired. The increase in heterozygosity is the underlying cause of hybrid vigour. The increase in heterozygosity gives a higher mean value, which is proportional to the increase in the production traits.

So, the correct answer is option D.