My ward is in 10th grade. He wants to go to US to do his UG.Our dilemma at this juncture is that, if he pursues his 11th and 12th from Karnataka Board of Education (Known as PUC or Pre-University Course), will that be recognised by US universities? Is 12 years of schooling mandatory to take admission in a US college?
FOA every University has its own eligibility criteria. Speaking in general, no, US Universities don't discriminate between state board or central board scores as long as the %age is good 'cause it's ultimately their own entrance exam scores that counts along with the TOEFL or IELTS scores.
And about the '12 years of schooling' query, if your ward wants to go for a UG course, he obviously will complete his 12 years of schooling first. So, don't worry about that. Just make sure he is meritorious in whatever he does academically.