I am pursuing BSc. Bio general from CU. My combination is Botany, Zoology, Molecular Biology. Which books I should read?

Well it's never that a single book can satisfy you , No , you have to take two or three books of the subject by different writers then only you'll be able to cover all the topics of your syllabus . But these are some books which has the most of the matter that you'll need and they will be even helpful in upcoming years too.

Soil science- Dilip Kumar Das

Agronomy- Reddy and Reddy /S R Reddy (a little informative than the former but former is the best one)

Horticulture- Jitendra Singh (basics of horticulture)

Plant pathology- D P Tripathi

Genetics - Elements of genetics by phundan sing ( it is the best book short but informative matter is available and also the book is hard to find but I know it because it was available in our library) otherwise B D Singh book is also good and easily available in market

Economics - you should take 11 & 12 eco books they were helpful and the other book Agriculture Economics ( by Suba or sudha) also Managerial Economics by Jain , Khandelwal, Choudhary(really good one ,ask for this one from your commerce subject friends)

Forestry- introduction to forestry by SR Reddy and C Nagamani

Plant physiology(bio chemistry)- SN panday BK Sinha

Extention - OP Dhama and GL Ray (communication book)

And in 1 year 11 the and 12 th Biology NCERT book is your best helping hand.