In India,$Jaya$ and $Ratna$ are varieties of which crop that were developed for the Green Revolution?

Consider the following four statements $(a-d)$ regarding the successful cultivation of chickpea in an area where bacterial blight is common:
$(a)$ Spraying of Bordeaux mixture.
$(b)$ Control of the disease vector.
$(c)$ Use of disease-free seeds.
$(d)$ Use of disease-resistant varieties.
Which of the above are the most effective strategies for managing this disease?

Crop rotation is carried out for

Disease resistance in crops is obtained by:

Norin-$10$ gene is

In which step of plant breeding for genetically variable crops is germplasm collection performed?