Molecular and phenotypic characterisation of NS maize inbred lines.

Abstract

Maize has great phenotypic and genotypic variability. In this study a diverse set of maize inbred lines used in breeding programmes as a potential source of alleles with positive effects on important agronomic traits, was characterised at phenotypic and molecular level. Furthermore, alleles specific to heterotic groups were identified and potentially significant associations between markers and important agronomic traits which could be employed in marker assisted selection were determined. Ninety eight inbred lines from four heterotic groups were analysed. Thirty six microsatellite markers were used to obtain parameters for genetic diversity and three claster analyses were employed based on molecular data. The field trials were set in randomised block design with three replications during two years to acquire phenotypic data. Descriptive statistics, analysis of variance, linear correlations and principal component analysis were performed for 13 traits. The associations between markers and traits were identified by the application of general and mixed linear model. The average number of alleles was 8,3, the average value of polymorphism information content was 0,64, whereas the percentage of rare alleles was 8,5%. Greater genetic diversity of BSSS inbred lines compared to the lines from Lancaster group were observed. More than one third of alleles were specific to only one of these two groups. The results of cluster analyses were to a large extent in agreement with each other. Analysis of variance indicated statistically significant differences in traits among inbred lines, years and locations. Cluster analysis based on phenotypic data was in less consistent with pedigrees of the inbred lines than the cluster analysis based on molecular data. Principal component analysis grouped inbreds into heterotic groups and indicated their general characteristics. A large number of identified marker alleles with stable positive effects on grain yield suggested the potential importance of these markers in maize

Kukuruz je biljna vrsta koja ispoljava veliku fenotipsku i genetičku varijabilnost. U ovom radu izvršena je fenotipska i molekularna karakterizacija divergentnih inbred linija kukuruza koje se koriste u oplemenjivačkim programima i koje predstavljaju mogući izvor alela sa pozitivnim uticajem na agromonski važne osobine. Takođe, identifikovani su aleli karakteristični za određene heterotične grupe i utvrđene su potencijalno značajne veze između markera i agronomski važnih svojstava primenom asocijativne analize, sa ciljem dalje primene u marker asistiranoj selekciji. Analizirani materijal sastojao se od 96 inbred linija iz četiri heterotične grupe. Trideset šest mikrosatelitskih markera korišćeno je za izračunavanje parametara diverziteta genskih lokusa. Primenjene su tri klaster analize na podacima dobijenim molekularnom analizom. Poljski ogledi su postavljeni u toku dve godine, po potpuno slučajnom blok sistemu sa tri ponavljanja. Deskriptivna statistika, analiza varijanse, linearne korelacije i analiza glavnih komponenti izračunate su za 13 osobina. Veze između markera i osobina utvrđene su primenom opšteg i mešovitog linearnog modela. Prosečan broj alela iznosio je 8,3, prosečna polimorfnost pojedinačnih lokusa iznosila je 0,64, a procenat retkih alela 8,5% po lokusu. Uočen je veći genetički diverzitet kod BSSS nego kod Lancaster linija. Više od trećine alela bilo je karakteristično za samo jednu grupu. Rezultati klaster analiza su u velikoj meri bili u međusobnoj saglasnosti. Analiza varijanse ukazala je na postojanje statistički značajnih razlika osobina među inbred linijama, godinama i lokalitetima. Rezultati klaster analize fenotipskih podataka bili su u manjoj meri saglasni sa pedigreima linija, nego rezulati analize molekularnih podataka. Analiza glavnih komponenti izdvojila je linije prema heterotičnim grupama i istakla njihove opšte karakteristike. Veliki broj utvrđenih alela markera sa stabilnim pozitivnim efektima na prinos ukazuje na mogući značaj ovih markera u oplemenjivanju kukuruza.