My father is a farmer, I am lone son, I want them as my dependent, how much is their present income from all source limit to show them as my dependent in india

Please clarify - are you trying to claim your father who lives in India as your dependent for purposes of US income tax filing? If so - any dependants you claim on your US taxes must be a US citizen, resident alien, US national, or resident of Canada or Mexico. So it seems your father does not qualify. Further, his income must be less than $3,650 and you must provide at least half his support.