Lettuce seedlings development index in different substrates using multivariate analysis
The quality seedlings production, which is dependent on the substrate used, are fundamental to the establishment of vegetable crops. The aim of this study was to evaluate the quality of lettuce seedlings in response to addition of vermiculite concentrations of substrates (pine bark, coconut fiber and peat) through the use of multivariate statistical methods. An experiment was conducted, where treatments consisted of vegetable substrates combinations and three concentrations of vermiculite (0, 25 and 50%), were added to the substrates. Lettuce crop was used as test plant, from which we evaluated the seedlings emergence, the root volume (RV), roots and shoot fresh and dry phytomass, true leaves number and the smaller true leaf height. The principal component analysis and canonical discriminant function analysis were applied. The seedling emergence was lower when using coconut fiber as substrate. The other variables evaluated have had maximum increments when using peat. The first two principal components explained 84.70% of the total variance. The RV was the most important for seedlings produced, variable highlighted by the use of the two multivariate methods, which has proved to be suitable for qualitative assessments of seedlings. The quality of lettuce seedlings is not affected by the addition of vermiculite in substrates composed of pine bark, coconut fiber and peat.