Genetic variability of seed yield and seed yield components of autochthonous Lolium perenne L. populations

Abstract

The aim of this study was to examine genetic variability, heritability and correlation of seed yield components and seed yield of progenies of autochthonous populations and cultivars of perennial ryegrass, and that on the basis of these results distinguish genotypes that would be later used in the creation of new local cultivars of perennial ryegrass. Research was carried out on experimental fields and laboratories of the Agricultural Institute of Republic of Srpska in Banja Luka in 2007. and 2008., on 6 natural populations of perennial ryegrass collected in Bosnia and Herzegovina and two cultivars, Maja and Calibra as standard. Following parameters were analyzed: number of generative tillers per plant, time of flowering, spike length, number of spikelets per spike, seed yield per spike and plant and 1000 seed weight. Analysis of the results of the number of generative tillers per plant indicates a statistically significant difference in the studied populations and cultivars of perennial ryegrass. The highest average number of tillers per plant was found in the cultivar Maja (193.8), and the least number was detected in population Dragocaj (78.9), so statistical differences were highly significant. The longest period to beginning of flowering was determined in cultivar Calibra (56.5 days) and the shortest in population Laminci (43 days). The average length of spike of perennial ryegrass in the studied population was 22.78 cm and was significantly lower than cultivar Maja. Statistically significant differences between populations and variety Maja in the number of spikelets per spike were detected. The average seed yield per spike of studied populations was in level with cultivar Maja and 37.5% higher compared with variety Calibra. In the studied populations of perennial ryegrass seed yield ranged from 5.21 g (Dragocaj population) to 15.40 g (Kupres population). Weight of 1000 seeds was highest in the variety Calibra (2.60 g) and lowest in population Maglajani (1.94 g). Proportion of genetic to phenotypic variance for time of flowering, the number of generative tillers, seed yield per spike and plant and 1000 seed weight indicate that the variability of these traits in this collection of genotypes, largely derived from plant genotype. In this investigation, the presence of a highly significant positive genetic correlation was found between time of flowering and spike length (0.98), time of flowering and 1000 seed weight (0.97), number of generative tillers and seed yield per plant (0.91) and spike length and 1000 seed weight (0.98).