What yield and income can greater yam give and where do I sell large tubers?

Greater yam can produce large tubers and good tonnage per plant when grown long with staking and good soil, but treat yield as a wide range that depends on variety, sett size, support and crop length. The honest market picture is that in much of India greater yam is a local and homestead crop with seasonal, festival and regional demand rather than a big organised buyer chain, so income depends on nearby market appetite and on selling at the right time. It stores reasonably as a fresh tuber, which gives some flexibility. If you have a tribal or local market that values yam, it can be a steady earner; do not assume a premium export price. Check current local rates and demand with your KVK and nearest mandi.