The correct option is A Heterosis is maintained for a longer duration
Heterosis, hybrid vigor, or outbreeding enhancement, is the improved or increased function of any biological quality in a hybrid offspring. An offspring exhibits heterosis if its traits are enhanced as a result of mixing the genetic contributions of its parents. These effects can be due to Mendelian or non - Mendelian inheritance. Heterosis, 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. Hence, it is more profitable in vegetatively propagated plants as they do not involve sexual reproduction and so hybrid vigor is not lost in subsequent generations. So, it is desirable in vegetatively propagated plants because heterosis can be maintained for longer duration so the correct answer is option a.