Which of the following is considered as the root of any breeding program?

Which method is used to develop all the cultivated varieties of sugarcane?

Consider the following four measures $(1-4)$ that could be taken to successfully grow chickpea in an area where bacterial blight disease is common.
$(1)$ Spray with Bordeaux mixture
$(2)$ Control of the insect vector of the disease pathogen
$(3)$ Use of only disease-free seeds
$(4)$ Use of varieties resistant to the disease
Which two of the above measures can control the disease?

Dwarf wheats were developed by

Examples of high-yielding and disease-resistant wheat varieties were introduced in India in:

Mating between two individuals differing in genotype to produce genetic variation is called: