Browsing by Author "Abayol, K. N."

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    COMPARISON OF SEVERAL METHODS FOR THE ASSESSMENTOF Cylas INFESTATION OF SOME ADVANCED SWEET POTATO (Ipomoea batatas (L.) Lam.) BREEDING LINES IN NIGERIA.
    (Department of Agric Education, Nasarawa State University, Keffi., 2011-02-01) Abayol, K. N.; Ogaraku, A. O.; Afuape, S. O.
    Field trials were conducted at three locations in Nigeria to assess the levels of Cylas infestation of some advanced sweet potato (Ipomoea batatas (L.) Lam) breeding lines at pre-release stage using several methods. These locations include: Nyanya, Makurdi and Umudike. Sweet potato genotypes were planted in a randomized complete block design (RCBD) with three replicates at each location. At four months maturity, sweet potato roots were harvested and assessed for Cylas spp. infestation using four methods. Of the four methods used, two distinguished between clean and infested roots, while two took into consideration the extent of individual root damage. Significant difference (P<0.01) in levels of infestation expressed as percentage clean yield was observed but a nonsignificant difference was observed in extent of individual root damage expressed as Cylas mean scores. Comparison of these methods was done using correlation and regression analysis tools. Correlation studies showed significant associations (P<0.01) among all the methods. Whereas methods A and D were positively correlated (R2=0.627) methods B and C showed negative correlation (R2=-0.737). Comparison of both methods A and B however showed positive correlation with a lower R2=0.475 and methods C and D showed negative and significant correlation with the value of R2=-0.477. This indicates a stronger correlation between methods A and D/B and C and a lesser correlation between methods A and B/C and D. Thus, the more rapid method A can be used as an approximation of the more time-consuming method D. And with the limitation of time, methods A, B or C would be appropriate in assessing Cylas spp. damage in sweet potato roots.
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    EFFECT OF PHENOLIC ACID OF SOME ADVANCED SWEETPOTATO (Ipomoea batatas (L.) Lam) BREEDING LINES AT PRERELEASE STAGE ON Cylas spp. INFESTATION AT NY ANYA, NIGERIA.
    (Department of Agricultural Science,Nasarawa State University, Keffi., 2011-02-01) Abayol, K. N.; Ogaraku, A. O.; Afuape, S. O.
    The effect of phenolic acid on susceptibility of some advanced sweetpotato (Ipomoea batatas (L.) Lam) breeding lines to Cylas spp. was investigated at Nyanya, Nigeria. Sweetpotato genotypes were planted in a randomized complete block design (RCBD) with three replicates at the location. Results of Cylas infestation assessment showed that variation in susceptibility did exist among lines. Whereas ANOVA established significant difference (P<0.01) in levels of infestation expressed as percentage clean yield, a nonsignificant difference was observed in extent of individual root damage expressed as Cylas mean scores. Sound roots were picked at random and transported to the laboratory for phenolic acid determination. Total phenolic acid which was expressed as chlorogenic acid equivalent (CAE)/mg dry weight was found to differ considerably among breeding lines. The orange-fleshed line Centennial (2.05 mg/g dry weight) had the highest total phenolic acid while the white-fleshed line NRSP/05/3B (0.22 mg/g dry weight) had the lowest content. Also, separation of methanol extract of sweetpotato roots using silica-gel thin layer chromatography showed that only caffeic acid was present in two breeding lines - NRSP/05/022 and NRSP/05/1B. The large differences found in such a small germplasm collection suggest that selecting or breeding sweetpotato with high phenolic acid is possible. Further investigation was done to identify relationships among 16 variable traits using correlation analysis. Correlation studies showed significant relationship (P<0.05, P<0.001) between total phenolic acid and four variable traits. A highly significant relationship (P<0.001) between total phenolic acid and Cylas mean scores (r=0.43) indicate potential biological activity on Cylas spp. infestation thereby suggesting that total phenolic acid and indeed type of phenolic acid is associated with Cylas susceptibility among these breeding lines.