Dihybrid cross (9:3:3:1)द्विसंकर संकरण (9:3:3:1)
NCERT Fig 4.7 · Class 12 Biology · Chapter 4 · interactive diagram
Parts and their functions
- Parent: round, yellow (RRYY) (जनक: गोल, पीले (RRYY)) — Homozygous dominant for both seed shape (R) and seed colour (Y); gametes all RY.
- Parent: wrinkled, green (rryy) (जनक: झुर्रीदार, हरे (rryy)) — Homozygous recessive for both traits; gametes all ry.
- F₁ hybrid (RrYy) (F₁ संकर (RrYy)) — All seeds round and yellow: R is dominant over r and Y over y.
- Four kinds of gametes (चार तरह के युग्मक) — Law of independent assortment: RY, Ry, rY, ry — each 1/4 — because the R/r pair separates independently of the Y/y pair.
- Round, yellow — 9/16 (गोल, पीले — 9/16) — At least one R and at least one Y: 9 of the 16 boxes.
- Wrinkled, yellow — 3/16 (झुर्रीदार, पीले — 3/16) — rr with at least one Y: 3 boxes.
- Round, green — 3/16 (गोल, हरे — 3/16) — At least one R with yy: 3 boxes.
- Wrinkled, green — 1/16 (झुर्रीदार, हरे — 1/16) — rryy: only 1 box.
Steps
- 1 · RRYY × rryy → F₁ RrYy (round, yellow).
- 2 · F₁ makes 4 gamete types: RY, Ry, rY, ry.
- 3 · F₂: 16 boxes → 9 : 3 : 3 : 1.
Original diagram drawn by Simple Learning Hub, based on NCERT Fig 4.7. Report a mistake