Hydroponic screening for selection of aluminium tolerant rice (Oryza sativa L.) genotypes at seedlings stage using different indices

In acid soil, Al is solubilised into a phytotoxic form, Al(H2O)63+ which is known as Al3+. Al toxicity is the primary growth-limiting factor for plants in acid soils. Breeding of rice for Al tolerance are important approach for increasing grain yield in acid soils. In the present endeavour, rice genotypes were screened at seedling stage based on vigour index, root tolerance index and hematoxylin staining in stressed nutrient solutions to select the tolerant genotype(s) against Al toxicity. It was observed that use of different screening indices for Al toxicity tolerant genotypes of rice have given different results. Thus, screening of tolerant genotypes using one index may lead to inappropriate conclusion. Comparing all the selection indices it was found that Radhunipagal and UBKVR-16 were the common genotypes which fallen into tolerant class for every index. Finally genotypes were grouped into different clusters using D2 statistic to find out whether the tolerant genotypes fall into one cluster. Those two Al toxicity tolerance genotypes were grouped into one cluster, which strengthens our findings.