Genetic analysis of rooting ability of transplanted rice (Oryza sativa L.) under different water conditions

• Published in: Journal of experimental botany Vol. 58; no. 2; pp. 309 - 318
• Main Authors: Ikeda, H, Kamoshita, A, Manabe, T
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Oxford University Press 01.01.2007; Oxford Publishing Limited (England)
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Chromosomes; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Heritability; Lowlands; Non-flooded paddy; Oryza - drug effects; Oryza - genetics; Oryza - metabolism; Oryza sativa; Phenotype; Phenotypic traits; Plant roots; Plant Roots - drug effects; Plant Roots - genetics; Plant Roots - metabolism; Plants; Quantitative Trait Loci; Rice; rice (Oryza sativa L.); root pruning; Root shoot ratio; Seedlings; Soil - analysis; SPECIAL ISSUE PAPER; transplanting; Water - metabolism; Water - pharmacology; Water relations, transpiration, stomata; water scarcity; water scarcity; rice (Oryza sativa L.); root pruning; transplanting; Non-flooded paddy; Oryza sativa; Monocotyledones; Root; Gramineae; Angiospermae; Spermatophyta
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erl162

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 (ΔRW) 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 ΔRW 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 ΔRW 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.