Identification of phosphorus efficient rice cultivars under low P nutrition through hydroponic based screening

Phosphorus (P) is one of the major nutrients required by plants. A higher portion of P in lowland rice soils is found in unavailable forms due to fixation. Therefore, continuous application of P fertilizer to rice (Oryza sativa L.) is needed to obtain a satisfactory yield. Identification and subsequent cultivation of high yielding rice varieties which can withstand low level of P is a better alternative to the continuous P application. The objective of this study was to categorize Sri Lankan rice varieties according to their response to P deficient conditions. Forty eight rice varieties including three old improved varieties and 45 new improved varieties were evaluated at deprived (10 μM P) and sufficient (50 μM P) P levels in a nutrient solution culture. Multiple plant traits; number of tillers, root and shoot dry weights and P content in shoot tissues were assessed at 52 days after planting. Rice variety Bg 94-1 gained higher biomass and P uptake (i.e. shoot P contentmg/plant). Simultaneously, At402 had lower biomass gain and shoot P content. Rice varieties were grouped into two distinct clusters based on their responses to P deficiency such as biomass gain, P uptake and number of tillers per plant. This study showed that At 405, Bg 94-1, At 307, Bg 304, Bg 300 and At 354 are promising rice varieties with higher response to low level of P supply.