QTL mapping for stay-green in maize (Zea mays)Ai-yu Wang1, Yan Li1, and Chun-qing Zhang2State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology,College of Agronomy, Shandong Agricultural University, Taian 271018, China.Received 1 June 2011, accepted 11 October 2011.Wang, A.-y., Li, Y. and Zhang, C.-q. 2012. QTL mapping for stay-green in maize (Zea mays). Can. J. Plant Sci. 92:249C1256. Stay-green is a desirable character for crop production. In order to explore the genetic basis for stay-green traitsin maize, 112 polymorphic simple sequence repeat (SSR) markers were used to analyze 189 F2individuals derived from asingle cross of inbred lines A150-3-2 (a stay-green inbred line) and Mo17 (a normal inbred line). A total of 14 quantitativetrait loci (QTLs) were detected for three stay-green related traits, green leaf area per plant at 30 d after flowering (GLA2),green leaf area per plant at the grain-ripening stage (GLA3), and left green leaf number per plant at the grain-ripeningstage (LLN). Single QTL explained from 3.16 to 12.50% of the phenotypic variance. Among them, three were majorQTLs. In addition, we analyzed the other two traits, green leaf area per plant in the whole growing period (GLA1) andtotal leaf number per plant in the whole growing period (TLN), and detected eight QTLs for them. Our results will behelpful to the maize breeders for marker-assisted selection.Key words: Maize, stay-green, quantitative trait loci, simple sequence repeatWang, A.-y., Li, Y. et Zhang, C.-q. 2012. Cartographie des QTL du caractere stay-green chez le mas(Zea mays). Can. J.Plant Sci. 92: 249C1256. Le caractere stay-green est souhaitable pour les cultures. Afin den preciser lorigine gene tique chezle mas, les auteurs ont recouru a 112 marqueurs microsatellites (SSR) pour analyser 189 individus de la F2issus dununique croisement des ligne es endogames A150-3-2 (lignee stay-green) et Mo17 (ligne e normale). En tout, ils ont decele14 locus quantitatifs (QTL) pour trois caracte res associe s au caracte re stay-green, a savoir la superficie des feuilles vertespar plant 30 jours apres la floraison (GLA2), la superficie des feuilles vertes par plant a la maturation du grain (GLA3) etle nombre de feuilles vertes par plant a la maturation du grain (LLN). Des QTL simples expliquent de 3,16 % a 12,50 % dela variabilite phe notypique. Parmi eux figurent trois importants QTL. Les auteurs ont e galement analyse les deux autrescaracte res, soit la superficie des feuilles vertes par plant durant la periode vegetative (GLA1) et le nombre total de feuillespar plant durant la periode ve getative (TLN), et de cele huit QTL. Ces re sultats aideront les ame liorateurs a se lectionnerdes varie te sa laide de marqueurs.Mots cles: Mas, stay-green, QTL, SSRMany researchers have demonstrated that a positivecorrelation exists between crop yield and duration ofgreen leaf area (Heath and Gregory 1938; Tollenaarand Daynard 1978; Thomas and Smart 1993). There-fore, the stay-green trait strongly attracts crop breedersbecause the leaves remain green even after the grain-ripening stage. Jiang et al. (2004) classified stay-greeninto two groups: functional stay-green and non-functional stay-green. Functional stay-green genotypeshave been drawing more and more attention due toincreased photosynthetic capacity in the final stageof plant growth, and consequent high grain yield(Gentinetta et al. 1986; Thomas and Howarth 2000),increased nutritional quality of stems and leaves forherbivorous animals (Gentinetta et al. 1986; VanOosterom et al. 1995), and increased tolerance to bioticand abiotic stress (Thomas and Smart 1993; Xu et al.2000a). On the other hand, non-functional stay-greengenotypes lack photosynthetic activity, although theleaves remain green in the final stage of plant develop-ment (Thomas and Howarth 2000; Cha et al. 2002).The genetic basis of functional stay-green traits iscomplicated. Thomas (1987) initially characterized astay-green mutant sid in Festuca pratensis, whichindicated it is a qualitative character. Thereafter, severalresearchers drew the same conclusion in soybean andrice (Guiamet et al. 1990; Cha et al. 2002). Furthermore,a cytoplasmic gene (cyt G) was identified as control-ling the stay-green trait in soybean (Guiame tetal.1990). Many more researchers, however, have demon-strated that functional stay-green is a largely polygene-regulated quantitative trait. Genetic mapping of thequantitative trait loci (QTLs) for stay-green has been1Ai-yu Wang and Yan Li contributed equally to this paper.2Corresponding author (e-mail: cqzhangsdau.edu.cn).Abbreviations: GLA1, green leaf area per plant in the wholegrowing period; GLA2, green leaf area per plant at 30 d afterflowering; GLA3, green leaf area per plant at the grain-ripeningstage; LLN, left green leaf number per plant at the grain-ripeningstage; LOD, logarithm of odds; MCIM, mixed-model-basedcomposite interval map