Which of the following steps in plant breeding is very tedious and time-consuming?

From which species was resistance against $Phytophthora$ in potato obtained?

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?

Which one of the following combinations would a sugarcane farmer look for in the sugarcane crop?

Which crop developed by mutation breeding shows resistance to yellow mosaic virus?

In which method are $Gamma$-rays used?