Pre Tuber Application of Fluridone: Effect on Vegetative Growth and Seed Tuber Dormancy in Yam (D. alata)

Abstract

Aims: This paper seeks to determine the effect of pre tuber application of fluridone (FLU) on vegetative growth, seed tuber production and dormancy in yam (D. alata). Study Design: The pot experiment was laid out as a completely randomized design (CRD) with 4 treatments and 3 replicates, and  24 plants per treatment. In the anatomical study, each young seed tuber portion per treatment represented a replicate. In storage, the experiment was laid out as CRD with 4 treatments and each mature seed tuber as a replicate. Place and Duration of Study: Field and storage studies were conducted in the Department of Crop and Soil Science, university of Port, Harcourt while the anatomical work was carried out in the yam pathology laboratory, IITA, Ibadan Nigerian. The study covered the period from April 2011 to April 2012. Methodology: Treatments were: water (control), 10 µM FLU, 5 µM abscisic acid (ABA), and 10 µM FLU + 5 µM ABA. 1 ml of the treatment was injected into the primary nodal complex (i.e., the organ from which tubers originate) of the yam plants prior to tuber formation. Data collected include plant height, leaf number, leaf length and width, tuber number and dry matter content. At least 24 small tuber portions per treatment were sectioned and examined for internal signs of sprouting. At the end of the growth study, tubers were harvested, stored and observed for date of external sprouting. Results: Fluridone absorption resulted in the appearance of whitish patches on leaves but this effect wore out by 3 week after treatment. Root dry weight increased (P=0.05) by 29% in FLU compared to control (10.9g). In contrast, ABA reduced root dry weight by 17% compared to control whereas; the application of ABA two days after FLU (FLU+ABA treatment) led to 13% increase in root dry weight compared to ABA alone. Number of nodes per plant reduced (P=0.05) in ABA. All tissues sections observed at 75 days after vine emergence did not show any clear internal signs of sprouting. Conclusion: Single pre tuber application of I ml fluridone, led to patchy bleaching of leaves, a characteristic effect of fluridone, as well as increased root development. However, prolonged exposure to fluridone may be required to significantly prevent seed tuber dormancy in yam