Molecular Toolkit for Inbred Line Screening and Purification of Maize (Zea mays)
Maria Cristina C. Heredia1, Rovel Emman G. Austria1, and Eureka Teresa M. Ocampo2,*
1Institute of Plant Breeding, University of the Philippines Los Baños,
College, Laguna 4031, Philippines
2Institute of Crop Science, College of Agriculture and Food Science,
University of the Philippines Los Baños, College, Laguna 4031, Philippines
*Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.;
ABSTRACT
Inbred lines are produced by self-pollinating maize plants for several cycles resulting in populations that are morphologically similar and genetically stable, and pure. Inbred lines are valuable parental materials in the development of hybrid varieties. Hence, genetic purity of inbred lines should be maintained so that hybrids produced are always of the same quality and genetic make-up. However, purification of inbreds by conventional methods can be difficult since morphological features can be similar in plants that are highly diverse. An alternative is to use molecular markers to screen, identify, and verify the genetic similarity of inbred lines. In this study, simple sequence repeats (SSRs) were used to identify genetically similar plants. One hundred and ten SSR markers representing the ten chromosomes of maize were selected from published literature and databases. The published primers of these markers were used to amplify the marker regions from isolated DNA of five maize inbreds (Sukmaraga 9, Sukmaraga 16, Lamuro 8, CW80116) and five native varieties (Pastilan, Banlon, TinuguibB, CalimpusA, KabagtikA). The amplified DNA bands were scored for polymorphism. Thirty-two polymorphic markers (representing at least two for every chromosome) were selected and utilized for preliminary inbred line screening. The first and second batch of screening among known Philippine inbreds showed that the yellow maize inbreds Pi17 and Pi23 gave acceptable homozygosity of ≥90%, while white maize inbred lines P9 and P29 were highly heterozygous. Selected plants were selfed and advanced into the succeeding generation. True inbred lines were distinguished among the conventionally characterized Philippine ‘inbred’ lines with the assistance of SSR markers.
Key words: inbred, polymorphism, SSR markers
INTRODUCTION
About 1.8 million Filipinos depend in maize production, making it as the second most important crop in the Philippines (Gerpacio et al. 2004). Due to the increasing demand, coupled with decreasing area for production, there is a need to develop maize varieties that are high yielding and resistant/tolerant to biotic or abiotic stresses. Hence, hybrid line development has been one of the most exploited researches among the private and public institutions. For this, inbred lines are continuously being developed for hybrid development (Schrag et al. 2010). . . . read more
REFERENCES
CHOUKAN R, HOSSAINZADEH A, GHANNADHA M, WARBURTON M, TALEI A, MOHAMMADI S. 2006. Use of SSR data to determine relationships and potential heterotic groupings within medium to late maturing Iranian maize inbred lines. Field Crops Research 95:212-222.
DANIEL I, ADETUMBI J, OYELAKIN O, OLAKOJO S, AJALA M, ONAGBESAN S. 2012. Application of SSR Markers for Genetic Purity Analysis of Parental Inbred Lines and Some Commercial Hybrid Maize (Zea mays L.). American Journal of Experimental Agriculture 2(4):597-606.
DOYLE L, DOYLE J. 1987. A rapid DNA Isolation procedure for small quantities of fresh leaf tissue. Phytochemical Bulletin. 19:11-15.
ENOKI H, SATO H, KOINUMA K. 2002. SSR analysis of genetic diversity among maize inbred lines adapted to cold regions of Japan. Theoretical and Applied Genetics 104:1270-1277.
GERPACIO RV, LABIOS JD, LABIOS RV, DIANGKINAY EM. 2004. Maize in the Philippines: Production system, Constraints and Research Priorities. Mexico, D.F.: CIMMYT. 37p.
GETHI JG, LABATE JA, LAMKEY KR, SMITH ME, KRESOVICH S. 2002. SSR variation in important U.S. maize inbred lines. Crop Science 42:951-957.
LI Y, DU J, WANG T, SHI Y, SHONG Y, JIA J. 2002. genetic diversity and relationships among Chinese maize inbred lines revealed by SSR markers. Maydica 47:93-101.
LIU K, GOODMAN M, MUS S, SMITH JS, BUCKLER E, DOEBLEY J. 2003. Genetic structure and diversity among maize inbred lines as inferred from DNA microsatellites. Genetics 165:2117-28.
LU-JIANG L, KE-CHENG Y, GUANG-TANG P, TING-ZHAO R. 2008. Genetic diversity of maize populations developed by two kinds of recurrent selection methods investigated with SSR markers. Agricultural Sciences in China 7(9):1037-1045.
NGUYEN TV, DOAN TTB, LEO AE, BUI CM, TAYLOR PWJ, FORD R. 2012. Application of microsatellite markers to fingerprint and determine the representational diversity within a recently established elite maize inbred line breeding program. Journal of Agricultural Science 4(6):258-266.
PRASANNA BM, PIXLEY K, WARBURTON ML, XIE CX. 2010. Molecular marker-assisted breeding options for maize improvement in Asia. Molecular Breeding 26:339-356.
PHUMICHAI C, DOUNGCHAN W, PUDDHANON P, JAMPATONG S, GRUDLOYMA P, KIRDSRI C, CHUNWONGSE J, PULAM T. 2008. SSR-based and grain yield-based diversity of hybrid maize in Thailand. Field Crops Research 108: 157-162.
RANATUGA MAB, MEENAKSHISUNDARAM P, ARUMUGACHAMY S, MHESWARAN M. 2009. Genetic diversity and analysis of maize (Zea mays L.) inbreds determined with morphometric traits and simple sequence repeat markers. Maydica 54(1):113-123.
SCHRAG TA, MOHRING J, MELCHINGER AE, KUSTERER B, DHILLON BS, PIEPHO HP. 2010. Prediction of hybrid performance in maize using molecular markers and joint analyses of hybrids and parental inbreds. Theoretical and Applied Genetics 120:451-461.
SHEHATA AI, AL-GHETHAR HA, AL-HOMAIDAN AA. 2009. Application of simple sequence repeat (SSR) markers for molecular diversity and heterozygosity analysis in maize inbred lines. Saudi Journal of Biological Sciences 16:57-62.
WANG FG, TIAN H, ZHIAO J, YI H, WANG L, SONG W. 2011. Development and characterization of a core set of SSR markers for fingerprinting analysis of Chinese maize varieties. Maydica 56:7-18.
XIE C, ZHANG S, LI M, LI X, HAO Z, BAI L, ZHANG D, LIANG Y. 2007. Inferring genome ancestry and estimating molecular relatedness among 187 Chinese maize inbred lines. Journal of Genetics and Genomics 34(8):738-748.
