The ability to stay-green (SG) in later stages of the crop cycle is a valuable trait for plants cultivated in standard or stressful environments. Few QTLs studies for SG have been conducted in temperate maize, apart from some experiments carried out with Chinese lines. The aim of our study was to identify QTLs related to SG in temperate maize using PHG39, an important SG line in private breeding. We developed two large F2 mapping populations by crossing PHG39 to the no stay-green (NSG) lines B73 (Corn Belt Dent) and EA1070 (European flint). Samples of individuals of the extreme tails (high and low) of the populations for visual score were genotyped. We found an association between markers and SG in three regions at bins 1.04–1.09, 5.02 and 10.04–10.06. The association was strong for some markers in chromosome 1, for example, for bnlg1556 the frequency of the SG allele was 0.75 and 0.34 in the high and the low tail, respectively. Furthermore, for this marker the homozygote’s with the SG allele had 4 times more chlorophyll than the homozygote’s with the NSG allele 2 months after flowering. Some alleles most likely conferred SG because they increased the maximum chlorophyll content at flowering while other alleles did by diminishing the rate of senescence. The SG conferred by some alleles could be functional as some favourable alleles for SG were also favourable for kernel weight. Regardless of the physiological basis of the SG, the significant markers detected could be useful for marker assisted selection.
KeywordsChlorophyll content Fluorescence Photosynthesis Senescence Zea mays
Part of thesis submitted by M Kante in partial fulfilment of requirements for a MS degree from the International Centre for Advanced Mediterranean Agronomic Studies (CIHEAM). Research supported by the Spanish National Plan for Research and Development (project code AGL2010-22254/C02-00 and AGL2013-48852-C3-1-R). M Kante acknowledges a Grant from the West Africa Agricultural Productivity Program (WAAPP) and B Ordás a “Ramon y Cajal” contract from the Ministry of Economy and Competitiveness of Spain.
- Boer MP, Wright D, Feng L, Podlich W, Luo L, Cooper M, van Euwijk FA (2007) A mixed-model quantitative trait loci (QTL) analysis for multiple-environment trial data using environmental covariables for QTL-by-Environment interactions, with an example in maize. Genetics 177:1801–1813. doi: 10.1534/genetics.107.071068 CrossRefPubMedPubMedCentralGoogle Scholar
- Borrell AK, Mullet JE, George-Jaeggli B, Van Oosterom EJ, Hammer GL, Klein PE, Jordan DR (2014) Drought adaptation of stay-green sorghum is associated with canopy development, leaf anatomy, root growth, and water uptake. J Exp Bot 65:6251–6263. doi: 10.1093/jxb/eru232 CrossRefPubMedPubMedCentralGoogle Scholar
- Câmara TMM (2006) Mapeamento de QTLs de caracteres relacionados à tolerância ao estresse hídrico em milho tropical. Doctoral thesis, Escola Superior de Agricultura Luiz de Queiroz, University of São Paulo, Piracicaba. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-04042007-145739/. Accessed 26 Sep 2014
- Lynch M, Walsh B (1998) Genetics and analysis of quantitative traits. Sinauer Associates Inc, SunderlandGoogle Scholar
- Minitab Inc (2010) Chapter name, meet minitab, p 16Google Scholar
- Weir BS (1996) Genetic data analysis II, Editorial. Sinauer Associates, SunderlandGoogle Scholar
- Yu Y, Wang R, Shi Y, Song Y, Wang T, Li Y (2007) Genetic diversity and structure of the core collection for maize inbred lines in China. Maydica 52:181–194 (ISSN 0025-6153)Google Scholar