Simplify the following text for a Grade 11 native English-speaking person.
Original: Nikolai Ivanovich Vavilov ( -- January 26 , 1943 ) was a prominent Russian and Soviet botanist and geneticist best known for having identified the centres of origin of cultivated plants .
Simplified: Nikolai Ivanovich Vavilov ( 25 November 1887 â `` 26 January 1943 ) was a Russian botanist and geneticist .