Theory question 106
Crop Improvement(a) State the laws of Mendel.
(b) Discuss three advantages and two disadvantages of (i) introduction (ii) selection in crop improvement.
Show the model answer
(a) First law (segregation): the two factors (alleles) for a character separate during gamete formation so each gamete carries only one
Second law (independent assortment): factors for different characters are passed on independently of each other
(b)(i) Introduction – advantages: quick way of getting improved varieties; widens genetic base for breeding; new crops/varieties with high yield or resistance; cheap. Disadvantages: may not adapt to local conditions; may bring in new pests/diseases
(ii) Selection – advantages: uses locally adapted plants; simple and cheap; improves yield, quality and resistance over time. Disadvantages: slow; cannot create new characters (only uses existing variation)
State both laws, then three advantages and two disadvantages for each method.