One way of incorporating desired characters into crop varieties is hybridization. In this process, there is crossing between genetically dissimilar plants. Which one of the following crossings will not refer to hybridization?

Correct — D, Intragenic. The stem supplies the definition itself — hybridisation is a cross between genetically dissimilar plants — and the standard classification runs by how far apart the two parents stand. A cross between two varieties of the same crop, between two species of one genus, or between two different genera all qualify, and every one of those names begins with 'inter-', meaning between. 'Intra-' means within. An intragenic matter is one confined inside a single gene, so there are no two dissimilar parents and no cross at all, which is why this is the one option that cannot describe hybridisation.

• (a)Intervarietal — A cross between two varieties of the same crop. This is the commonest form of hybridisation in Indian plant breeding and clearly involves two dissimilar parents.
• (b)Interspecific — A cross between two species of the same genus. The parents are further apart than in an intervarietal cross, so it is more difficult, but it is hybridisation all the same.
• (c)Intergenic — Another 'inter-' term. It stands for the category of crossing between plants of two different genera — triticale, the wheat-rye hybrid, is the classic result — which is the hardest of the three but still a genuine cross.

Crop variety improvement works along a few routes, and hybridisation is one of them: two genetically dissimilar parents are crossed so that desirable characters from each — yield, disease resistance, drought tolerance, maturity time — come together in the progeny. The crosses are grouped by the distance between the parents, running from two varieties of a crop, through two species of a genus, to two different genera.

The item can be answered on a prefix alone, without any agriculture. Three options point outward to a second, different parent and one points inward to a single gene, so the odd one out is settled by 'inter-' against 'intra-'. One point about the printed paper is worth noting honestly: option (c) is printed as 'Intergenic', while the textbook name for a cross between two genera is 'intergeneric', and in genetics 'intergenic' has a separate meaning of its own, describing the stretches of DNA that lie between genes. The bank keeps the booklet's wording. Either way the option is an 'inter-' term and the answer is untouched. Remember too that hybridisation is not the only route to a better variety — selection from existing populations, mutation breeding, and the introduction of a single gene from another organism are the others, and the third of those is what produced GM crops.

• Hybridisation is crossing between genetically dissimilar plants, as the stem itself states.
• The three standard categories are intervarietal, interspecific and intergeneric — between varieties, between species of one genus, and between genera.
• The prefix decides the answer: 'inter-' means between two different things, 'intra-' means within one.
• Triticale, obtained from a wheat and rye cross, is the best-known intergeneric hybrid.
• Other routes to variety improvement are selection, mutation breeding and the introduction of a gene from another organism.

• Reading past the prefix and treating all four options as varieties of crossing.
• Assuming the hardest-sounding option must be the wrong one; an intergeneric cross is difficult but real.
• Confusing hybridisation with the transfer of a single gene, which is a different route to improvement.

Asked as a negative item — three genuine categories of crossing against one term that describes something inside a gene rather than a cross.

• practice — not a real PYQ

  Triticale, a crop obtained by crossing wheat and rye, is an example of which kind of hybridisation?

  • (a)Intervarietal
  • (b)Interspecific
  • (c)Intergeneric
  • (d)Intravarietal

  Answer(c) Intergeneric — wheat and rye belong to different genera.

• practice — not a real PYQ

  Which one of the following is not a method of crop variety improvement?

  • (a)Hybridisation
  • (b)Selection
  • (c)Mutation breeding
  • (d)Transpiration

  Answer(d) Transpiration — the loss of water vapour from a plant, a physiological process and not a breeding method.