Genetic Variability of Morphological and Cultural Characteristics in Sweetpea (Lathyrus odoratus L.)

Abstract

In Japan, the use of forced culture conditions to produce sweetpea (Lathyrus odoratus L.) cut flowers has flourished. The tendril-less trait that results in compound leaves instead of tendrils is a very important trait for forced flower production because removing unnecessary tendrils markedly increases the amount of labor and production management costs. Thirty-five morphological and cultural characteristics were examined in 38 sweetpea cultivars. We analyzed the relationship between characteristics, especially those deemed important for reducing labor costs such as the tendril-less trait, and calculated correlation coefficients. Cluster analysis was also employed to evaluate the dataset and it showed that 38 cultivars could be classified into 3 clusters. Cluster I cultivars are recommended as garden-type plants because their initial flower buds were too late to be forced. Cluster II cultivars are suitable as cut flower type plants. Cluster III cultivars are appropriate as garden or container-type plants because the peduncles were too short to use as cut flowers. Furthermore, the results of principal component analysis indicated some important factors for classification of cultivars. These were consistent with the results of cluster analysis. Our analysis of the morphological and cultural characteristics of sweetpea grown under conditions to force flowering provides a foundation for the efficient breeding of this important horticultural plant.