Divergence of lucerne (Medicago sativa L.) genotypes for yield components

Abstract

Lucerne is a polymorphic, xenogamous and autotetraploid species characterised by extremely high genetic variability. The objective of this study was to analyse a genetic distance among 48 lucerne genotypes of a different origin (the U.S., France, Serbia, Romania, Bulgaria, Netherlands, Sweden, Denmark, Germany Czech Republic, Iran and Turkey). A hierarchical cluster analysis was used to determine similarities and differences in genotype responses to environmental factors. A cluster analysis of lucerne yield components showed divergence and a degree of similarity in the genotypes response for the traits analysed over a three-year study (2001-2003). A dendrogram was constructed using the hierarchical analysis for all the traits that consisted of a different number of different-sized groups and subgroups. The dendrogram of phenotypic differences included two distinct groups. The first group consisted of two genotypes, Ghareh Yon Geh from Iran and Triumph from Romania, which had very similar responses over the studied period. They also produced the highest yields of forage and dry matter (g/plant). The second group of genotypes was the largest and very heterogeneous. It was divided into a number of subgroups linked together in the dendrogram at different distances, indicating that the materials were highly divergent. This analysis provides a clear picture of the interrelationships among the lucerne genotypes and makes possible the selection of superior ones to be used as parental components in hybridisation and the development of higher-yielding, better-quality lucerne cultivars.

Lucerka je polimorfna, ksenogamna, autotetraploidna vrsta izrazito velike genetičke varijabilnosti. Cilj rada je bio da se analizira genetička udaljenost 48 genotipova lucerke različitog geografskog porekla (SAD, Francuska, Srbija, Rumunija, Bugarska, Holandija, Švedska, Danska, Nemačka, Češka, Iran i Turska). Primenjena je hijerarhijska analiza grupisanja (hierchical cluster analyses) za utvrđivanje sličnosti i razlika u reakciji genotipova lucerke na faktore sredine. Analiza grupisanja komponenti prinosa lucerke ukazala je na divergntnost genotipova i stepen sličnosti u reakciji za ispitivane osobine tokom tri godine ispitivanja (2001-2003). Konstruisani dendogram primenom jednostruke hijerarhijske analize za sve ispitivane osobine sastoji se od različitog broja i veličina grupa i podgrupa. Dendogram fenotipskih razlika sastoji se od dve grupe genotipova. U prvoj grupi se nalaze genotip Ghareh Yon Geh - iz Irana i Triumph - iz Rumunije koji su veoma slično reagovali tokom perioda ispitivanja. Ovi genotipovi su ujedno ostvarili najveći prinos krme i suve materije (g/biljci). Druga grupa genotipova je najbrojnija. Ova grupa je vrlo heterogena i deli se na više podgrupa koje se u dendogramu vezuju na različitim udaljenostima, što govori o velikoj divergentnosti materijala. Ovom analizom pruža se mogućnost jasnog sagledavanja međusobnih odnosa ispitivanih genotipova lucerke kao i izbor superiornih genotipova kao roditeljskih komponenti u hibridizaciji i stvaranju prinosnijih i kvalitetnijih sorti lucerke.