QTL Associated with Maize Kernel Oil, Protein, and Starch Concentrations; Kernel Mass; and Grain Yield in Illinois High Oil × B73 Backcross‐Derived Lines

Abstract

Illinois long‐term selection strains of maize (Zea mays L.) have been useful for identifying genomic regions controlling kernel oil, protein, and starch concentrations. To identify kernel trait quantitative trait loci (QTL) in a genetic background more relevant to practical breeding, 150 BC1‐derived S1 lines (BC1S1s) were produced from Illinois High Oil and recurrent parent B73. Oil, protein, and starch were measured in BC1S1s and in Mo17‐topcross hybrids (TCs). Kernel mass of BC1S1s and grain yield of TCs were also determined. Starch was positively correlated with mass in BC1S1s (rp = 0.67**, α ≤ 0.01) and with yield in TCs (rp = 0.59**). Oil was negatively correlated with mass in BC1S1s (rp = −0.29**) and with yield in TCs (rp = −0.30**). Oil was negatively correlated with starch in BC1S1s (rp = −0.75**) and TCs (rp = −0.66**). A genetic map with length = 1486 cM was created with 110 markers. Multiple regression models with QTL detected by composite interval mapping (CIM) explained 46.9, 45.2, 44.3, and 17.7% of phenotypic variance for oil, protein, starch, and mass, respectively, in BC1S1s and 17.5, 22.9, 40.1, and 28.7% for oil, protein, starch, and yield, respectively, in TCs. A 22 cM‐interval on chromosome 6 in BC1S1s included oil, protein, and starch QTL, including a QTL explaining 36.7% of the BC1S1 phenotypic variation for oil. No yield QTL were detected in this region. Introgression of this QTL into breeding lines might increase oil while maintaining yield.

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

“…Previous studies on QTL detection for grain protein content have used F 3 populations derived from the IHP x ILP cross (Goldman et al,l993); S 1 families derived from the IHO x ILO cross ; IHO x B73 backcross-derived lines (Wassom et al, 2008); F 2:3 , F 2:4 , and F 7:8 populations from normal corn and BHO inbreds (Zhang et al, 2008); F 2:3 derived from ASK high-oil (Li et al, 2009); and F 2:3 and BC 2 F 2 populations derived from normal corn x popcorn inbreds (Liu et al, 2008). In addition, qzPRO1-5-1, which was detected at bin 5.02-5.04 with a 11.3% contribution to phenotypic variation in the present study, was also identified by Goldman et al (1993), Li et al (2009), andWassom et al (2008); qx-PRO1-6-1, which was detected at bin 6.05-6.06 with a 6.4% contribution to phenotypic variation, has also been identified by Goldman et al (1993), Melchinger et al (1998), Willmot et al (2006), Zhang et al (2008), Li et al (2009), Liu et al (2008, Wassom et al (2008), and Li et al (2009); and qPRO1-8-1, which was detected at bin 8.03-8.04 with a 13.4% contribution to phenotypic variation in the present study, has also been identified by Berke et al (1995), Melchinger et al (1998), , Willmot et al (2006), Zhang et al (2008), Liu et al (2008), Wassom et al (2008), and Li et al (2009). The consistency of detection of these QTLs across studies suggests that they are less influenced by their environmental and genetic backgrounds.…”

“…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).…”

“…Miller and Brimhall (1951) reported that the total grain oil content was not related to the total grain protein content and was instead strongly positively related with grain protein content in the germ. 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.…”

Desenvolvimento de modelo genético-estatístico para mapeamento de QTLs em progênie de irmãos completos, com aplicação em cana-de-açúcar

“…Ao longo dos anos, várias metodologias foram propostas para a detecção e estimação dessas regiões, o que permitiu um acúmulo considerável de informações sobre base genética de caracteres quantitativos de importância agronômica para as principais culturas, como milho (CARDINAL et al, 2001;MANGOLIN et al, 2004;SABADIN et al, 2008;SIBOV et al, 2003;ZHAO et al, 2006;WASSOM, 2008aWASSOM, , 2008b, soja (CHAPMAN et al 2003;LI;PFEIFFER;CORNELIUS, 2008;TASMA et al 2001), tomate (CHEN et al 1999GORGUET et al, 2008;MAZZUCATO et al, 2008), dentre outras. Entretanto, ao observar as propriedades biológicas dos materiais em estudo, os trabalhos podem ser classificados em dois grupos: i) mapeamento de QTLs para populações experimentais (com linhagens endogâmicas); ii) mapeamento em populações obtidas com cruzamento de indivíduos não endogâmicos, como por exemplo as progênies de irmãos completos (LIN et al, 2003).…”

“…No CIM, buscou-se remover os efeitos de QTLs localizados fora da região mapeada, o que permitiu uma melhora significativa no poder do mapeamento. Modelos CIM são muito utilizados para mapeamento de QTLs em espécies vegetais com importância econômica, como milho (CARDINAL et al, 2001;MAN-GOLIN et al, 2004;SABADIN et al, 2008;SIBOV et al, 2003;WASSOM, 2008a;WASSOM, 2008b;ZHAO et al, 2006), trigo (ABATE; LIU; McKENDRY, 2008;MACCAFERRI et al, 2008), arroz (CHO et al, 2007;SEMAGN et al, 2007) …”