Question

a) Name the tropical sugarcane variety grown in south india. How has it helped in improving the sugarcane quality grown in north india ?
b) Identify ‘a’, ‘b’ and ‘c’ in the following table:

No.	Crop	Variety	Insect pests
1.	Brassica	Pusa gaurav	(a)
2.	Flat bean	Pusa sem 2 Pusa sem 3	(b)
3.	( c)	Pusa sawani Pusa A-4	Shoot and fruit borer

Answer 1

The tropical sugarcane variety grown in south India is Saccharum barberi(new variety made after breeding north and south indian varieties). It is successfully grown in south india as it is high yielding and disease resistant variety.

Complete answer:
The sugarcane variety of north india is Saccharum barberi which has poor sugar content and is poor yielding variety but it is disease resistant variety.Where as the sugarcane variety of south india is Saccharum officinarum which has high sugar content, thick stem and high yielding but it was not disease resistant.

These two varieties were successfully crossed to get a sugarcane variety combining the desirable characters. New variety Saccharum Barberi produced having thick stem, high sugar content and grew well in north india. The table given below provides information regarding insect /pest resistant varieties of different crops.

crop	variety	Insect pests
Brassica(rapeseed mustard)	Pusa gaurav	Aphids
Flat bean	Pusa sem 2	Jassids, aphids, and fruit borer
Okra (bhindi)	Pusa SawaniPusa A-4	Shoot and fruit borer

Note: All disease and pest resistant varieties can be made by doing plant breeding.
Plant breeding: is the purposeful manipulation of the plant species in order to create desired plant types that are better suited for the cultivation, giving better yield and disease resistance.
Plant breeding techniques are responsible for the success of the green revolution in the country.
It started about 9000-12000 years ago.
Purpose of plant breeding is :

To increase crop yield
Improve quality
Increase tolerance
Resistance to pathogens
Produce crops having short maturity duration.