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Root system architecture in genetically diverse populations of grain sorghum compared with shallow and steeply rooted monocultures
Author(s) -
Adams Curtis B.,
ReyesCabrera Joel,
Nielsen Jackson,
Erickson John E.
Publication year - 2020
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.1002/csc2.20237
Subject(s) - biology , monoculture , sorghum , root system , agronomy , root (linguistics) , lateral root , botany , horticulture , arabidopsis , philosophy , linguistics , biochemistry , gene , mutant
The genetic uniformity of monocultures extends belowground to the genetic controls over the architectural configuration of the root system. We hypothesized this may encourage inefficiency in resource acquisition compared with crops with diversity in root system architecture among plants. Here, we report on an evaluation of root systems in grain sorghum [ Sorghum bicolor (L.) Moench] populations phenotyped by crown root angle as “shallow” and “steep” rooted, and diverse mixtures (shallow, intermediate, and steep), at four N rates (0, 20, 100, and 200 kg N ha −1 ) in a sandy soil with a plow layer. Differences in the spatial distribution of root mass among architecturally contrasting populations were confirmed by direct measures in the field, which has not been previously reported in sorghum. This confirmation, plus confirmation of differences in root N distribution with soil depth, indicate that soil C and N dynamics would differ among sorghum populations differing in root system architecture. Patterns in root length density (RLD) by N rate indicated N‐based limitation on root proliferation at low N levels and a N‐induced suppression of proliferation at high N levels. There was no strong evidence that diverse architectural mixtures would result in tangible improvements in resource acquisition, as they generally had intermediate root mass and did not differ in RLD relative to architecturally contrasting monocultures. The similarity of RLD across rooting architectural types was one of several observed indicators of root growth plasticity, which could be a mechanism to alleviate physical constraints of the plants’ inherent first‐order rooting structure in taking up soil resources.