Research Symposium-2013

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Browsing Research Symposium-2013 by Author "Aluwihare, Y.C."

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    Quantitative Assessment of Leaf Color Change in Response to Phosphate Deficiency Tolerance in Rice
    (Uva Wellassa University of Sri Lanka, 2013) Aluwihare, Y.C.; Lelwala, R.; Ishan, M.; Sooriyapathirana, S.D.S.S.; Sirisena, D.N.; Samarasinghe, W.L.G.
    Phosphate deficiency tolerance (PDT) is one of the important traits in improving rice varieties. Annual expenditure on phosphate fertilizers for rice is Rs.1158.4 millions in Sri Lanka. Application of phosphate fertilizers also causes many other environmental and health problems (Wickramasinghe et al., 2009). If PDT rice varieties can be developed, they can be grown with reduced fertilizer applications, higher profit margin, and minimum negative effects of phosphate applications (Wissua and Ae, 2001). Because of the phosphate deficiency, the leaf color is changed. If the color differences in leaves can be quantitatively measured, it can be used to assess the PDT of different rice varieties (Fageria et al., 1988). The present study was conducted to screen selected traditional and improved rice varieties developed by Rice Research and Development Institute (RRDI), Batalagoda (Bg) for PDT using the leaf color change measurements in a quantitative approach. Methodology A total of 10 rice genotypes (nine varieties: Bg 358, H 10, H4, Bg 360, Bg 403, Bg 379-2, Bg 352, H 7 and MAS and the landrace: Suduheenati) were grown in a field at RRDI, Bathalagoda where no fertilizer has been applied for last 30 years. Plants were maintained with standard management practices except no phosphate application. The leaf color measurements; L*, a* and b* were recorded in four replicates per plant on the sixth week after planting using a spectrophotometer (CR-10, Konika Minolta, Tokyo, Japan). L* measured the darkness/lightness range of the visual color from black (-L*) to white (+L*), a* measured the range from green (-a*) to red (+a*) while b* measured the range from blue (-b*) to yellow (+b*). The quantitative estimates, C* (chroma; estimate of dullness/sharpness of the visual color) and H* (hue angle; estimate of the overall visual color) were calculated using the following equations (Melgosa, 2000).