QTL detection for grain oil and starch content and their associations in two connected F2:3 populations in high-oil maize

Abstract

High-oil maize (Zea mays L.) has special value in animal feed and human food. Two hundred and eight-four and 265 F 2:3 families developed from two crosses between one high-oil maize inbred and two normal dent maize inbreds were evaluated for grain oil and starch contents under two environments. Using composite interval mapping, 1-6 QTL for each trait were detected under each environment and in combined analysis in both populations. Only one common QTL across two environments in each population and across two populations were found for starch content. Among the detected QTL, nine digenic interactions with small effects were identified. Comparison of single-trait QTL and the results of multiple-trait QTL mapping showed that oil content might be complicatedly correlated with starch content. Although singletrait QTL with the same parental effects for both traits and oil-starch QTL were all detected at the same genetic bin 6.04 as the cloned high-oil QTL (qHO6) with no unfavorable effects on grain weight, our results did reflect the difficulty to realize simultaneous improvement on grain oil and starch contents. Of course, these results should be validated in further experiments under more environments using RILs, NILs and other permanent populations.

QTL verification of grain protein content and its correlation with oil content by using connected RIL populations of high-oil maize

“…A positive relationship between grain protein and oil content has been reported in studies using Illinois maize strains (Goldman et al, 1993;Lambert, 2001;Wassom et al, 2008), BHO (Zhang et al, 2008), ASK high-oil (Li et al, 2009;Wang et al, 2010), and popcorn germplasms (Liu et al, 2008). Curtis et al (1968) showed that the total germ weight and percentage increased with selection of oil and fatty acid composition in IHO after 65 generations, and the protein content also increased.…”

“…Since Hopkins (1899) first began to investigate selection of maize grain chemical compositions over 100 years ago, several germplasms have been developed, including Illinois high protein (IHP), Illinois low protein (ILP), Illinois high oil (IHO), and Illinois low oil (ILO) (Dudley et al, 1977;Lambert, 1992, 2004) germplasms. To date, many researchers have demonstrated the genetic mechanisms contributing to grain protein and oil contents by using statistical and molecular models (Miller and Brimhall, 1951;Dudley et al, 1977;Lambert, 1992, 2004;Goldman et al, 1993;Berke and Rocheford, 1995;Song et al, 2004;Wassom et al, 2008;Zhang et al, 2008;Li et al, 2009;Wang et al, 2010).…”

“…However, more recently, several studies have demonstrated positive correlations between grain protein and oil contents (Dudley and Lambert, 2004;Wassom et al, 2008;Zhang et al, 2008). Further research has attempted to reveal the genetic mechanisms underlying kernel composition traits by mapping QTLs using different genetic germplasms such as IHP and ILP (Goldman et al, l993;, IHO and ILO (Alrefai et al, 1995;Berke and Rocheford, 1995;Laurie et al, 2004;Willmot et al, 2006;Wassom et al, 2008), Beinongda high-oil (BHO) (Song et al, 2004;Zhang et al, 2008), tropical high-oil (Mangolin et al, 2004), Alexho Single-Kernel (ASK) high-oil (Zheng et al, 2008;Li et al, 2009;Wang et al, 2010;Yang et al, 2012), and popcorn (Liu et al, 2008) maize populations. Based on data obtained from these studies and from the public genetic linkage map of maize (www.maizegdb.org), 79 QTLs for grain protein content and 52 QTLs for grain oil content have been detected.…”

“…Therefore, the genetic mechanism underlying grain protein and oil content can be best revealed by using many different populations. In our previous study, 2 connected F 2:3 popu-lations were used to identify QTLs for grain protein and oil content, which were developed from 2 crosses between 1 inbred high-oil and 2 normal inbred maize lines (Li et al, 2009;Wang et al, 2010). Two connected recombinant inbred line (RIL) populations were previously derived and used to detect QTLs for ear kernel traits and grain oil content (Yang et al, 2012).…”

Detection of quantitative trait loci for kernel oil and protein concentration in a B73 and Zheng58 maize cross

“…However, no common QTL was shared between the two populations. Wang et al (2010) used composite interval mapping and mapped 1-6 QTLs for grain oil and starch content in two populations under different environments. Wang et al (2013) used a double haploid population and identified a total of 63 QTLs for oil content.…”