Variability and genetics of tolerance for aluminum toxicity in rice (Oryza sativa L.)
1995
Khatiwada, S.P.
Pregerminated seeds were grown in nutrient solution containing 30 ppm Al and normal nutrient solution and relative root length, relative shoot length, relative root weight, and relative shoot weight were determined at 14 day old seedling stage. Relative root length was more pronounced than the other three parameters for detecting the degree of tolerance. Of 62 varieties tested, 11 varieties namely Siyam Kuning, Gudabang Putih, Siyam, Lerno, Khao Daeng, Siyamhalus, Bjin 12, Kitan, Seribu Gantang, Bayar Raden Rati, and Padi Kanji were found more tolerant than the improved tolerant variety IRAT 104. Tolerant varieties Azucena, IRAT 104, and Moroberekan and sensitive varieties, IR45 and IR1552, were studied in detail and were used along with two other varieties to investigate the genetics of tolerance to aluminum toxicity by diallel analysis of relative root length. The diallel analysis showed the predominance of additive gene action along with the significance of other components. Graphical analysis of variance and covariance showed that IR45, IR29, and IR1552 had an excess of recessive alleles and Moroberekan, IR43, Azucena, and IRAT 104 with more dominant alleles for aluminum toxicity tolerance. The graphical analysis further indicated the partial dominance of the trait and the absence of epistasis. The high narrow sense heritability value obtained (0.82) suggested that pedigree method of breeding would be a suitable breeding strategy to develop cultivars tolerant to aluminum toxicity
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