title: Genetic variation for maize root architecture in response to drought stress at the seedling stage.
abstract: Although the root system is indispensable for absorption of nutrients and water, it is poorly studied in maize owing to the difficulties of direct measurement of roots. Here, 103 maize lines were used to compare root architectures under well-watered and water-stressed conditions. Significant genetic variation, with medium to high heritability and significant correlations, was observed for root traits. Total root length (TRL) and total root surface area (TSA) had high phenotypical diversity, and TRL was positively correlated with TSA, root volume, and root forks. The first two principal components explained 94.01% and 91.15% of total root variation in well-watered and water-stressed conditions, respectively. Thus, TRL and TSA, major contributors to root variation, can be used as favorable selection criteria at the seedling stage. We found that stiff stalk and non-stiff stalk groups (temperate backgrounds) showed relatively higher mean values for root morphological diversity than the TST group (tropical/subtropical background). Of the tested lines, 7, 42, 45, and 9 were classified as drought sensitive, moderately sensitive, moderately drought tolerant, and highly drought tolerant, respectively. Seven of the 9 extremely drought tolerant lines were from the TST group, suggesting that TST germplasms harbor valuable genetic resources for drought tolerance that could be used in breeding to improve abiotic stress tolerance in maize.
authors.affiliation: Maize Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China ; China Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture , China ; Agronomy College, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China.
authors.forename: Rongyao
authors.initials: R
authors.lastname: Li
authors.affiliation: Maize Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China ; China Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture , China.
authors.forename: Yijin
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Maize Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China ; China Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture , China.
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.affiliation: Maize Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China ; China Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture , China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Maize Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China ; China Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture , China.
authors.forename: Fengkai
authors.initials: F
authors.lastname: Wu
authors.affiliation: Maize Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China ; China Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture , China.
authors.forename: Moju
authors.initials: M
authors.lastname: Cao
authors.affiliation: Maize Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China ; China Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture , China.
authors.forename: Hai
authors.initials: H
authors.lastname: Lan
authors.affiliation: Triticeae Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China.
authors.forename: Yaxi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Maize Research Institute, Sichuan Agricultural University , Wenjiang 611130, Sichuan , China ; China Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture , China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Lu
keywords: drought tolerance; heterotic groups; maize; root system