Explanation

Both (a) and (b). In 1963 the increase in crop production was due to introduction of semi-dwarf varieties of wheat. Semi-dwarf wheat was developed by Norman E. Borlaug at International Centre for Wheat and Maize Improvement in Mexico. Semi-dwarf varieties of rice were developed from IR-8 (developed at International Research Institute Phillipines) and Taichung Native-1 (developed in Taiwan)