Question

Autotriploids are obtained by
A.Crossing diploid with haploid
B.Meiosis of an autohexaploid
C.Having one extra chromosome
D.Crossing tetraploid and diploid

Answer 1

Hint: When organisms having a double number of chromosomes produce gametes that fuse to form organisms with three homologs of a chromosome. Then they are termed as autotriploids.

Complete step by step answer:
An autotriploid has three sets of chromosomes in its karyotype. It has three homologs of each chromosome. Chromosomes are trisomic. An autotriploid is produced when a normal haploid gamete n fuses with a gamete that has not undergone meiosis i.e. it is diploid \[\;\left( {2n} \right).\] Therefore, the zygote form is triploid \[\;\left( {3n} \right).\]Triploids are also produced when gametes of a diploid n is fused with gametes of tetraploid \[\;\left( {2n} \right).\].organism. When triploid organism mates then gametes are produced with unequal ploidy and most of the organisms are sterile because of the presence of an additional chromosome in the set.

Hence, the correct option is D Crossing tetraploid and diploid.

Additional information: Autotriploids have large fruits and flowers and have a great commercial advantage over their diploid counterparts. Common triploid plants are watermelon, banana, potatoes, and Winesap apples.

Note:
An autotriploid is produced by non-disjunction during meiosis that leads to the production of diploid gametes which then fuses with a haploid gamete to form a triploid zygote.