Indian Society of Genetics & Plant Breeding
Genetic improvement in root traits is necessary to enhance
and stabilize yield of rice crop under rainfed ecosystem.
Drought stress induces abscisic acid (ABA) accumulation,
which in turn regulates root growth under drought. Hence,
screening of genotypes based of ABA-responsiveness of
root traits in simple hydroponics system can help to identify
genotypes which may have better root traits under field
drought stress conditions. Towards this objective, a set of
32 rice genotypes were phenotyped for root traits in 500 nM
ABA at seedling stage in hydroponics, and then evaluated
under drought stress (soil matric potential -70 kPa) at
anthesis stage in field conditions. When the 32 genotypes
were classified based on stress susceptibility index (SSI),
11 genotypes showed superior performance in both ABA
stress and yield under drought stress in field, while 12
genotypes performed poor under both conditions. The SSI
based classification of genotypes under ABA response as
well as drought matched with yield for 7 good performing
and 7 poor performing genotypes. Thus rice genotypes,
CR2624, Ching Moiramsbhi, IC526266, Moroberekan, NericaL26, Nerica-L42 and Sahbhagi Dhan, which exhibited
enhancement or stability in root length in response to ABA,
also showed stability in both root length and yield under
drought stress in field conditions. Single Nucleotide
Polymorphism (SNP) analysis led to the identification of 20
non-synonymous SNPs in 12 genes involved in root traits.
Clustering based on these SNPs could differentiate the
genotypes with better root traits from that with poor root
traits. This study shows that screening for ABAresponsiveness in root traits is a potential surrogate to
identify donors for better root traits under drought stress
in field conditions.
Keywords: Abscisic acid, drought tolerance, root phenotyping, stress susceptibility index, water use efficiency
Year: 2018
Volume: 78
Issue: 1
Article DOI: 10.5958/0975-6906.2018.00006.8
Print ISSN: 0019-5200
Online ISSN: 0975-6906
G. K. Krishna info_circle
Chandrapal Vishwakarma info_circle
Paulson Thomas info_circle
J. Aravind info_circle
Sitaram Kushwaha info_circle
Viswanathan Chinnusamy info_circle
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