title: Genetic analysis of rooting ability of transplanted rice (Oryza sativa L.) under different water conditions.
abstract: In order to assess the benefits of superior rooting ability of rice (Oryza sativa L.) for growth after transplanting under water-limiting conditions, genetic differences in the rooting ability of rice seedlings 30 d after sowing, with their visible roots either pruned or not pruned, were quantified by several root parameters 4 d after transplanting (DAT), under flooded or non-flooded paddy fields (four treatments in total), together with production traits at maturity. Ninety-eight recombinant inbred lines from the two japonica ecotypes, a lowland variety Otomemochi, and an upland variety Yumenohatamochi, were genotyped with 107 simple sequence repeat (SSR) markers. Otomemochi in general produced more adventitious roots, partitioned a greater proportion of biomass to roots, and had a greater increment of root dry weight (DeltaRW) at 4 DAT than Yumenohatamochi, but these variety differences were less clear under non-flooded conditions without root pruning. Several quantitative trait loci (QTLs) associated with rooting ability were identified mainly in chromosomes 1, 4, and 6 across the four treatments or in combined analysis. On the other hand, QTLs for DeltaRW around RM2357 in chromosome 5 and for maximum new root length in RM215-RM205 in chromosome 9 were found only under root pruning treatments and under non-flooded conditions without root pruning, respectively. Greater DeltaRW was associated with higher head dry weight per hill at maturity only in the non-flooded and root-pruning treatments. This study suggests the importance of rooting ability after transplanting and, possibly, other mechanisms for adaptation to non-flooded conditions.
authors.affiliation: Field Production Science Center, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Midoricho, Nishitokyo, 188-0002 Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ikeda
authors.forename: A
authors.initials: A
authors.lastname: Kamoshita
authors.forename: T
authors.initials: T
authors.lastname: Manabe
mesh_terms: D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D040641:Quantitative Trait Loci; D012987:Soil / Q000032:analysis; D014867:Water / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D012987:Soil; D014867:Water