Plant Breeding Methods (CS, HS 541)

Exercise 1 – Crop Germplasm and Reproduction Systems

Give complete answers, but be brief and specific. Show your work.

20 points total

1. You have been hired by an “underdeveloped country” to put together a collection of dry bean (Phaseolus) cultigens for use in local breeding programs. What 3 major sources of germplasm besides native cultivars from that country (they have already been placed in the collection) should be used first in forming the collection? List them in priority order, and give the reason they should be considered an important source (and why you gave it the priority shown).


2. Describe 3 hypotheses that Harlan presented in his book, Crops & Man, for the domestication of crops by man (how did the hunting-gathering tribes become agricultural)? Which hypothesis do you prefer?


3. What advantage is there to producing a hybrid by apomixis for commercial seed production over the standard method (crossing 2 inbred lines to produce commercial seed)? What disadvantage is there?


4. Describe 2 methods in which 2n gametophytes can become 2n sporophytes in an apomictic species.