Seed yield of lettuce in different sawing periods

Abstract

This paper is a result of researching the number of lettuce (Lactuca sativa L.) seed per plant in two sawing periods. The presumption was that the traits: total number of flowers and total number of flowers per head, are highly correlated and that they represent the components of seed yield. In the second sawing period the skipping of the heading phase was provoked. Skipping of the heading phase is the effect of the long day, when plants transfer to flowering phase from phase of 4-6 permanent leaves. This research aimed to investigate the decrease of the seed number depending on sowing time lettuce seed crop. Ten lettuce varieties (Nansen, Majska kraljica, Safir, Univerzal, Ravel, Atraction, Superble, Type-5140, Ljubljanska ledenka and Brauner) for total flower number and the number of flowers per flower head in two sawing periods were compared. Two-factorial trial in random block system with four replications was performed. The correlation of the two researched traits was medium (r = 0,706) without significance. Regression coefficient showed the correlation of these traits. Variance analysis showed that variance of genotype was not significant: the other factor, sowing time and interaction (genotype x sowing time) were not significant. The coefficient of phenotype variance was higher than the genetic variance coefficient for both traits.