Analysing genetic control of cooked grain traits and gelatinization temperature in a double haploid population of rice by quantitative trait loci mapping

Abstract

Cooking quality in rice grains is a complex trait which requires improvement. Earlier reports show varying genetic inXuence on these traits, except for a common agreement on waxy (Wx) and alkali degeneration (Alk) loci on chromosome 6. The present study involved 86 doubled haploid lines derived from an indica £ japonica cross involving IR64 and Azucena. Grain parameters viz., raw grain length (RGL), raw grain breadth (RGB), cooked grain length (CGL), cooked grain breadth (CGB), gelatinization temperature (GT), grain shape (RGS), length elongation ratio (LER) and breadth expansion ratio (BER) were subjected to mixed model mapping of quantitative trait loci (QTL). Segregation data of 175 markers covering a distance of 2395.5 cM spanning the entire genome were used. Fifteen main eVect QTLs were detected spread over the genome, except on chromosomes 4, 8 and 11. Thirty epistatic interactions signiWcantly inXuencing the traits were detected. Twelve of the main eVect QTLs were involved in epistatic interactions. One main eVect QTL associated with LER was detected near Alk locus. QTLs located for grain length on chromosomes 9 and 10 are reported for the Wrst time. Detection of many epistatic loci and involvement of main eVect QTLs in interactions demand for judicious selection of QTLs in markerassisted selection programmes.

Molecular mapping of grain physico-chemical and cooking quality traits using recombinant inbred lines in rice (Oryza sativa L.)

“…1) and showed perfect normal distribution, although some exceptions were observed as in the case of AC and ASV at both locations. A bell shaped phenotypic distribution with a wide range of variation was observed, suggesting quantitative inheritance similar to earlier observations (Aluko et al 2004;Ge et al 2005;Govindaraj et al 2009;Redona and Mackill 1998). Transgressive segregation was observed indicating the polygenic inheritance of the traits.…”

“…These correlations are in consistence with the studies of Lou et al (2009). In case of kernel dimensions after cooking, correlation was nearly similar to the studies of Ge et al (2005) and Govindaraj et al (2009). AC showed highly positive correlation with KLBC trait and also with ASV, an association previously reported by Zheng et al (2008).…”

“…ASV is a physical characteristic responsible for cooking time and the capacity to absorb water during cooking, and is inversely proportional to gelatinization temperature (GT). Govindaraj et al (2009) has reported the significant influence on GT by a QTL on chromosome 6 linked to Alk locus.…”

QTL Analysis for Drought Tolerance in Wheat: Present Status and Future Possibilities

“…Therefore, the identification of epistatic QTLs is essential for the development of efficient marker-assisted selection (MAS) schemes for complex traits such as drought tolerance, aimed at improving breeding efficiency [65]. However, only a few QTL studies have been conducted, which included detection of QTL × QTL interactions for adaptation to drought/water stress conditions.…”

Analytical and numerical comparisons of two methods of estimation of additive × additive interaction of QTL effects

“…The epistasis is a very important genetic parameter and a large number of additive × additive interactions have been detected in rice (Govindaraj et al, 2009;Mei et al, 2005;Norton and Price, 2010;Zhao et al, 2010a;Yu et al, 1997), soybean (Kang et al, 2009), wheat (Liang et al, 2010;Ma et al, 2005;Zhao et al, 2010b).…”