income tax

yes you will be treated as non resident

With the business purpose, I mean it will be professional income of online margin trading in stocks, CFD, Commodities etc. In such case, if I become Registered Tax Resident in Thailand, should I be treated as non-resident in India for this financial year?

"It is generally said that if one move outside India and stays for more than 182 days, in a financial year, on a salaried job, he will be treated as non-resident for income tax purposes. Will the above rule applies to business persons?"

No. 

The condition do not apply to residents visiting foreign countries on business tours. So, if you stay at least 60 days in India in this financial year, you will be treated as Resident Indian for FY 2018-19.
 

You are considered as not ordinarily resident Indian....

I do not mean business tour. If I take residence in a country outside India, take registration in that country's Tax registration system, stay out of India for more than 182 days, what will be my tax status in India?

"...stay out of India for more than 182 days, what will be my tax status in India?" 

As additional condition is also to be satisfied for Residential Status, IF YOU STAY UPTO 30th OF MAY in this FY, in India, you will be treated as ROR (because anyone of the two conditions of RNOR do not satisfy in your case); but if you move out of India permanently, before 29th May, 2018....... your status will be NRI for this FY.

Even if I do not have a salaried job?

then your status is not ordinarily resident.....

Residence in India.

6. For the purposes of this Act,—

[1] An individual is said to be resident in India in any previous year, if he—

[a] is in India in that year for a period or periods amounting in all to one hundred and eighty-two days or more ; or

[b] [***]

[c] having within the four years preceding that year been in India for a period or periods amounting in all to three hundred and sixty-five days or more, is in India for a period or periods amounting in all to sixty days or more in that year.

Explanation. 1—In the case of an individual,—

[a] being a citizen of India, who leaves India in any previous year as a member of the crew of an Indian ship as defined in clause [18] of section 3 of the Merchant Shipping Act, 1958 [44 of 1958], or for the purposes of employment outside India, the provisions of sub-clause [c] shall apply in relation to that year as if for the words "sixty days", occurring therein, the words "one hundred and eighty-two days" had been substituted ;

[b] being a citizen of India, or a person of Indian origin within the meaning of Explanation to clause [e] ofsection 115C, who, being outside India, comes on a visit to India in any previous year, the provisions of sub-clause [c] shall apply in relation to that year as if for the words "sixty days", occurring therein, the words "one hundred and eighty-two days" had been substituted.

Explanation 2.—For the purposes of this clause, in the case of an individual, being a citizen of India and a member of the crew of a foreign bound ship leaving India, the period or periods of stay in India shall, in respect of such voyage, be determined in the manner and subject to such conditions as may be prescribed.20

[2] A Hindu undivided family, firm or other association of persons is said to be resident in India in any previous year in every case except where during that year the control and management of its affairs is situated wholly outside India.

21[[3] A company is said to be a resident in India in any previous year, if—

[i] it is an Indian company; or

[ii] its place of effective management, in that year, is in India.

Explanation.—For the purposes of this clause "place of effective management" means a place where key management and commercial decisions that are necessary for the conduct of business of an entity as a whole are, in substance made.]

[4] Every other person is said to be resident in India in any previous year in every case, except where during that year the control and management of his affairs is situated wholly outside India.

[5] If a person is resident in India in a previous year relevant to an assessment year in respect of any source of income, he shall be deemed to be resident in India in the previous year relevant to the assessment year in respect of each of his other sources of income.

[6] A person is said to be "not ordinarily resident" in India in any previous year if such person is—

[a] an individual who has been a non-resident in India in nine out of the ten previous years preceding that year, or has during the seven previous years preceding that year been in India for a period of, or periods amounting in all to, seven hundred and twenty-nine days or less; or

[b] a Hindu undivided family whose manager has been a non-resident in India in nine out of the ten previous years preceding that year, or has during the seven previous years preceding that year been in India for a period of, or periods amounting in all to, seven hundred and twenty-nine days or less.

20. See rule 126.

21. Substituted by the Finance Act, 2016, w.e.f. 1-4-2017.

Amendment to section 6[3] by the Finance Act, 2015, w.e.f. 1-4-2016 was omitted by the Finance Act, 2016, w.e.f. 1-4-2016.

as per section 6, you are resident unless otherwise you moved out of India for employment purposes (not business purposes)

Sec 6(3) is inserted for companies ....

but here the query is about residential status of individual who's moving abroad on business tour

No my query is not for Residence status of Individual who is moving abroad on business tour. But Residence status of an Individual who is moving to another country for business or profession, taking up residence in that country with a 5 year residence visa and staying in India for less than 182 days in this financial year

When you move out of India for business purpose & you stay in abroad for more than 182 days then your status is non- resident...

But as you stay in India for more than 730 days in past 7 years & more than 182 days in 2 years out of preceeding 10 years, your status is not ordinarily resident...

I differ with you Rashmi mam... if he stays more than 60days in a f.y and stays 365 days or more in last 4 f.y.s immediately preceding that f.y, then he is a resident. for the purpose of ordinary and not ordinarily resident purpose also he'll be a ordinary resident. he can avail relief under DTAA signed between the respective countries. pls correct me if I'm wrong in my interpretation