Quantitative Trait Loci (QTL) involved
Studies have been conducted in different plants such as rice (Y. Kim et
al., 2020), grain legumes (Ye et al., 2018) and wheat (C. Li et al.,
2021) where they have reported different QTL and genes produced in
drought stress. Ranjan et al., (2022) has reported QTL, mRNAs, genes and
transcription factors that actively take part in response of RSA to
water stress. Among these various root traits, dry weight of root and
root length harbors maximum gene number that are expressed in response
to drought. For example, under drought QTL such as PRL3, PRL2, CRL1,
SRL2, SRL7, SRL9, and QTRL.cgb-3B are associated with root length in
maize (T. Li et al., 2017) and wheat (X. Liu et al., 2013) respectively.
Likewise in wheat, Qrdws.uwa-4AL and Qrdws.uwa-5AL are known to be
associated with root dry weight in wheat (Ayalew et al., 2017) and in
sorghum QTLs qRDW1_2, qRDW1_5, and qRDW1_8 are linked to root dry
weight (Mace et al., 2012). In rice, overexpression of OsNAC5 (Jeong et
al., 2013) and OsNAC10 (Jeong et al., 2010) were reported to enhance the
root diameter in drought stress. Kawai et al., (2022) has recently
reported that under mild drought conditions, QHB and OsWOX10 are
responsible for regulating diameter of lateral roots in rice. InBrassica napus , a gene BnaC03g45915D (ortholog of A. thaliana
gene RD29B) is found to be present within QTL qR/S-13-1 and showed
increased expression in dry conditions configuring plants to adapt to
drought conditions more efficiently (Prerostova et al., 2018). Analysis
of QTL that are associated with physiological and morphological traits
w.r.t drought tolerance helps to develop understanding about the genetic
architecture involved in drought responses and how it can be utilized to
produce crops that are well adapted to drought.