Root Architecture of Elephant Foot Yam (Amorphophallus paeoniifolius (Dennst.) Nicolson), at Different Phenological Phases

Elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson ), one of the tropical root crops, is gaining popularity not only as a food security crop but also as a cash crop due to its production potential and popularity as a starchy vegetable having high nutritive and medicinal values. Its cultivation is mainly confined to Asian countries. The crop is propagated vegetatively, through corms. Once planted, normally the corm bud starts sprouting within 30-60 days depending upon the soil moisture, corm size etc. Root initiation also starts at this stage. Efforts were made to study the root distribution pattern of elephant foot yam at different phenological phases, for two growing seasons of 2015-16, and 2016-17, both under drip irrigated and rainfed situations. Full corms of one kg each of the variety ‘Gajendra’ were planted in cement tanks of size 2 x 2 x 0.6 m filled with top soil. Texture, physical and chemical properties of the soil were studied. Root distribution was studied by way of destructive sampling of plants at various stages viz., sprouting, shoot emerging stage, shoot elongation stage, full emergence stage, and then at monthly intervals upto 6 months, senescence stage, and finally at maturity stage. Root parameters viz., maximum and average root length, root diameter, number of roots, fresh and dry weights, root volume etc were assessed. During initial stages, root growth was more under irrigated conditions and reached maximum at full emergence stage of crop and retained upto 5 MAP. Rainfed crop recorded more root growth during later stages (15-20% more). A maximum root length of 123 cm and 130 cm and a root volume of 890cc and 730cc were recorded by irrigated and rainfed crop respectively. Pattern of elimination of roots was almost same under both the conditions, and at senescence, only 30-40 % of the roots were present. All the roots were destroyed at maturity.