Genotypic and Environmental Variation in Nodal Root Growth of Post-rainy Season (<i>Rabi</i>) Sorghum

Soman, P.; Seetharama, N.

doi:10.1017/s001447970001992x

Cited by 3 publications

(1 citation statement)

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“…Our results in B. distachyon are consistent with observations in other species, such as Phalaris spp., ryegrass (Lolium spp. ; Cornish, 1982;Cornish et al, 1984), sorghum (Soman and Seetharama, 1992), barley (Crossett et al, 1975), and wheat (Passioura, 1972). Volkmar (1997), however, observed that soil drying around an already emerged nodal root system of wheat induced a 4-fold increase in its growth compared with the control, where no drought treatment was applied.…”

Section: Responsiveness To Soil Moisturementioning

confidence: 98%

Variation in Adult Plant Phenotypes and Partitioning among Seed and Stem-Borne Roots across Brachypodium distachyon Accessions to Exploit in Breeding Cereals for Well-Watered and Drought Environments

et al. 2015

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Seedling roots enable plant establishment. Their small phenotypes are measured routinely. Adult root systems are relevant to yield and efficiency, but phenotyping is challenging. Root length exceeds the volume of most pots. Field studies measure partial adult root systems through coring or use seedling roots as adult surrogates. Here, we phenotyped 79 diverse lines of the small grass model Brachypodium distachyon to adults in 50-cm-long tubes of soil with irrigation; a subset of 16 lines was droughted. Variation was large (total biomass, ×8; total root length [TRL], ×10; and root mass ratio, ×6), repeatable, and attributable to genetic factors (heritabilities ranged from approximately 50% for root growth to 82% for partitioning phenotypes). Lines were dissected into seed-borne tissues (stem and primary seminal axile roots) and stem-borne tissues (tillers and coleoptile and leaf node axile roots) plus branch roots. All lines developed one seminal root that varied, with branch roots, from 31% to 90% of TRL in the well-watered condition. With drought, 100% of TRL was seminal, regardless of line because nodal roots were almost always inhibited in drying topsoil. Irrigation stimulated nodal roots depending on genotype. Shoot size and tillers correlated positively with roots with irrigation, but partitioning depended on genotype and was plastic with drought. Adult root systems of B. distachyon have genetic variation to exploit to increase cereal yields through genes associated with partitioning among roots and their responsiveness to irrigation. Whole-plant phenotypes could enhance gain for droughted environments because root and shoot traits are coselected.

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