Dormancy break, sprouting and later tuber reproduction in response to different tuber sizes of tiger nut (Cyperus esculentus L.)

Dormancy release pattern, sprout growth and later reproduction were studied among various tuber sizes of Cyperus esculentus to determine effective methods to release dormancy and further to select suitable tuber size of this species in production. The results showed that medium tubers performed better during sprouting than large and small tubers under all pre-sprouting treatments. Pre-sprouting treatments at 25 degrees C, 35 degrees C, RT (room temperature) and -2 degrees C were effective in relieving dormancy in medium tubers. Tiller number from medium tubers were significantly higher under 25 degrees C, RT and 45 degrees C than under 35 degrees C and -2 degrees C. Shoot and root mass from medium tubers were significantly higher under the 25 degrees C, 35 degrees C and RT than under other treatments. Tiller and tuber numbers both decreased with decreasing tuber size, as did tuber yield after three months of growth. Furthermore, leftover mass decreased with decreasing tuber mass and remained unchanged at sprouting and maturity periods. A significantly negative allometric correlation was found between plant mass and tuber mass from small tubers. However, a significantly positive allometric correlation was found between tuber size and tuber number from large tubers. In conclusion, medium tubers had a competitive advantage in sprouting, growth and reproduction.