Screening and selection of low grain arsenic (As) accumulating rice germplasms under West Bengal condition B. ADHIKARI, M.K. BAG, R. D. TRIPATHI AND U. N. RAI 1 Rice Research Station, Chinsurah – 712 102, West Bengal 1 National Botanical Research Institute, Lucknow, U.P. ABSTRACT For developing (As) tolerant rice variety, screening and selection of As tolerant rice germplasms (low As containing grain) is an essential pre-requisite. Keeping this objective in mind, a collaborative research programme has been undertaken and three different As contaminated locations viz, Purbasthali-1, Birnagar and Beldanga-1(As content ranges from 10 μg /L to >50 μg /L) were chosen for field trials along with a control set at RRS, Chinsurah. During Boro 2007-2008, hundred (100) rice germplasms were grown at the said locations and all of the entries were evaluated. The result of the experimental trial revealed that out of the hundred entries, only seven entries are promising with respect to grain arsenic content. Arsenic content in grain was very high in three entries and low in four entries irrespective of locations. The result of the arsenic analysis of rice grains suggests that diversified rice germplasms have differential reactions towards uptake and translocation of arsenic into the grains and this differential reaction is mainly due to genotypic differences of the rice varieties. Key words: Aresenic, germplasm and tolerance Arsenic (As) hazard has become a global concern due to its ever increasing contamination in many regions in the world particularly in South-East Asia. It is potentially toxic to human beings causing severe diseases including cancer. Groundwater As contamination in the Bengal delta is known as the largest chemical disaster in history (Smith et.al., 2000). A large part of Ganga-Meghna-Brahmaputra plain with an area of 569,749 sq.km and population over 500 million is at risk (Chakraborty et.al., 2004). In West Bengal, 111 blocks of 12 districts are arsenic affected. Not only drinking water but also staple food grains like rice contain arsenic well in excess of permissible limit. Rice has been reported to accumulate As upto 1.8 mg kg -1 in grains and upto 92 mg kg -1 in straw (Abedin et al., 2002). Compared to other cereals (wheat, barley, maize etc.) rice accumulates much higher levels of As in the roots, shoots and grains (Duxbury and Panaullah., 2007). The study further revealed that the roots of rice and wheat grown in contaminated fields had 169-178 mg kg - 1 of arsenic, nearly 20 times higher than the 7.7 mg kg -1 in an uncontaminated location. Concentrations of arsenic in rice grain did not exceed the food hygiene concentration limit (1.0 mg of As kg -1 dry weight). The concentrations of arsenic in rice straw (up to 91.8 mg kg -1 for the highest As treatment) were of the same order of magnitude as root arsenic concentrations (up to 107.5 mg kg -1 ), suggesting that arsenic can be readily translocated to the shoot (Abedin et. al., 2001) Rice being the major food crop of As contaminated areas also, notable accumulation of As in grains of rice through As contaminated irrigation water is alarming. Arsenic uptake and accumulation in rice plant from irrigation water may differ depending on cultivars used (Xie and Huang, 1998). The high arsenic concentrations may have the potential for adverse health effects on the cattle and an increase of arsenic exposure in humans via the plant-animal-human pathway. Arsenic concentrations in rice plant parts except husk were not affected by application of phosphate (Abedin et. al., 2001). Decontamination of arsenic from soil is not being a feasible approach. So to produce arsenic free grain without compromising projected demand, development of arsenic tolerant rice cultivars which should be genotypic in nature is the best way of solution. For developing As tolerant rice variety, screening and selection of As tolerant rice germplasms (low As containing grain) is an essential pre-requisite. Keeping this objective in mind, a collaborative research programme with NBRI, Lucknow, U.P. has been undertaken at Rice Research Station, Chinsurah, West Bengal. MATERIALS AND METHODS Field experiment was conducted during Boro season 2007 – 08 at three different arsenic contaminated locations at different Agro-climatic Zones viz, Purbasthali-I (Burdwan), Birnagar (Nadia) and RRS, Chinsurah (Hooghly) (As content ranges from 10 μg l -1 to >50μg l -1 in ground water ). Birnagar is situated at district Nadia (22 0 41 / 23 // N and 72 0 51 / 24 // E) and As level in ground water is >10μg l -1 . Purbasthali-I is situated at district Burdwan (23 o 53 / N -22 o 56 / N Journal of Crop and Weed, 5(1): 251-254 (2009)