Evaluation of Agronomic Traits in Chromosome Segment Substitution Lines of KDML105 Containing Drought Tolerance QTL under Drought Stress

Matching the Expression of Root Plasticity with Soil Moisture Availability Maximizes Production of Rice Plants Grown in an Experimental Sloping Bed having Soil Moisture Gradients

“…Plasticity in root branching in a shallow soil layer and rooting in the deep soil layer KDML105 has widely been cultivated in rainfed lowland rice areas of Northeastern Thailand (Jongdee et al, 2006;Kanjoo et al, 2012). The rainfed lowlands are characterized by the presence of a hardpan, which impedes deep root development, and the soil moisture fluctuations between aerobic and anaerobic conditions in the upper soil layer above the hardpan, and therefore, root distributions are commonly shallow and most of available water tends to be limited to the shallow soil layer (Clark et al, 2002;Samson et al, 2002;Kato et al, 2013).…”

Functional roles of root plasticity and its contribution to water uptake and dry matter production of CSSLs with the genetic background of KDML105 under soil moisture fluctuation

“…KDML105 was shown to be susceptible to severe water deficit conditions (Cabuslay, Ito, & Alejar, 2002;Kanjoo et al, 2012;Kumar et al, 2006). A series of our studies showed that KDML105 is well adapted to the rainfed lowland conditions (Azhiri-Sigari, Fukai & Cooper, 1995;Kano-Nakata et al, 2013;Wade, Fukai, Samson, Ali, & Mazid, 1999) where not solely simple/progressive drought but SMF stress is also a major constraint to production.…”

“…Khao Dawk Mali 105 (KDML105) is an elite cultivar of aromatic rice mainly grown in rainfed lowland areas of North and Northeast Thailand which are prone to abiotic and biotic stresses such as salinity, drought, submergence, diseases and pest (Jantaboon et al, 2011;Jongdee, Pantuwan, Fukai, & Fischer, 2006;Kanjoo et al, 2012;Siangliw, Jongdee, Pantuwan, & Toojinda, 2007;Toojinda, Siangliw, Tragoonrung, & Vanavichit, 2003;Toojinda et al, 2005). Several studies have been carried out on the improvement of KDML105 under such stresses to increase grain yield.…”

“…Several studies have been carried out on the improvement of KDML105 under such stresses to increase grain yield. Through markerassisted selection, the development of pyramiding lines tolerant to submergence and resistant to brown plant hopper (Korinsak et al, 2016), backcrossed introgression lines tolerant to drought (Siangliw et al, 2007) as well as chromosome segment substitution lines (CSSLs) tolerant to drought and salinity (Kanjoo et al, 2011(Kanjoo et al, , 2012 have been reported.…”

“…CSSLs have been used to effectively identify root plasticity traits, with reduced confounding effects by the variation in genetic backgrounds due to other traits, in response to water deficit of different intensities Tran et al, 2014) and SMF conditions (Niones et al, 2012;Suralta et al, 2008b;Suralta & Yamauchi, 2008). Kanjoo et al (2012) developed CSSLs carrying drought tolerant (DT) QTLs on chromosomes 1, 4 and 8 (Lanceras, Pantuwan, Jongdee, & Toojinda, 2004) in the genetic background of KDML105. These CSSLs showed better adaptation and higher yield than the recurrent parent, KDML105 under drought stress conditions although the mechanism of such adaptation has not yet been studied.…”