These fast-growing markets could become the key to Cummins' future growth. Cummins is expanding capacities and setting up new facilities in these markets, as well as launching new products that meet the respective country's emission targets. It has strong tie-ins with some of the best-known names in the industry -- the 50:50 joint venture with leading Indian automaker Tata Motors ( NYS: TTM ) had a big role to play in pushing up Cummins' fourth-quarter joint venture income by 12%. Some months back, Cummins also joined hands with China-based construction equipment maker LiuGong. With production expected to begin next year, the partnership will help Cummins increase its presence in one of the largest truck markets in the world. The Westport edge For me, of all the tie-ins Cummins has, the one with Westport Innovations ( NAS: WPRT ) stands out. Westport's innovative technology enables gasoline engines to run on natural gas, which could change the future of automobiles.