QTLs for low nitrogen tolerance at seedling stage identified using a recombinant inbred line population derived from an elite rice hybrid

Abstract

Tolerance to low nitrogen conditions is a highly desired characteristic for sustainable crop production. In this study, we analyzed the genetic components associated with low N tolerance in rice at seedling stage, including main effects, epistatic effects of the quantitative trait locus (QTLs), and QTL by environment interactions (QEs), using a population of 239 recombinant inbred lines (RILs) from a cross between Zhenshan 97 and Minghui 63, the parents of an elite hybrid. A genetic linkage map with 253 DNA maker loci was constructed. Seedlings of RILs were cultivated in low N and normal N solutions. Root, shoot and plant weight in the two N treatments were measured and the relative weight of the two treatments for each trait was considered as measurements for low N tolerance. Four to eight QTLs with main effects were detected for each of the nine traits. Very few QTLs were detected in both low and normal N conditions, and most QTLs for the relative measurements were different from those for traits under the two N treatments, indicating very little commonality in the genetic basis of the traits and their relative performance under low and normal N conditions. A total of 103 digenic interactions were detected for the nine traits. While the epistatic effects collectively accounted for large proportions of the variation for several traits, the effects of QEs appeared to be trivial. It was concluded that low N tolerance of rice seedling had complex genetic basis that requires extensive studies for full characterization.

Quantitative Trait Loci and Crop Performance under Abiotic Stress: Where Do We Stand?: Table I.

“…Additionally, QTL clusters for GS activity on wheat chromosomes 2A and 4A coincided with the location of GS and GSr genes, respectively, and although QTL alleles for higher GS activity were associated with higher grain N, they showed little or no effects on grain yield components (Habash et al, 2007). QTLs for tolerance to low N have also been described in Arabidopsis (Loudet et al, 2003), rice (Lian et al, 2005), and barley (Mickelson et al, 2003).…”

Strategies for developing Green Super Rice

“…Using a high-density linkage map, Lian et al (85) analyzed the genetic components associated with low-N tolerance in rice at the seedling stage using a population of 239 recombinant inbred lines from a cross between Zhenshan 97 and Minghui 63. Seedlings were cultivated in both low-and normal-N solutions.…”

Genetic control of yield and yield components in winter oilseed rape (Brassica napus L.) grown under nitrogen limitation

“…However, only a small number of studies were carried out under abiotic stress, such as cold stress (Kole et al 2002;Asghari et al 2007), boron stress (Xu et al 2001) or phosphorus stress Ding et al 2012). In the context of N stress, QTL analyses have been performed on major cereal crops, including barley (Kjaer and Jensen 1995;Gorny and Sodkiewicz 2001;Mickelson et al 2003), maize (Hirel et al 2001;Coque et al 2008), rice (Lian et al 2005;Cho et al 2007) and wheat (Habash et al 2007;Laperche et al 2007) whereas there have been a couple of studies carried out on OSR (Gül 2002, Miro 2010.…”