Breeding Objectives and Selection Criteria for Milk Thistle [<i>Silybum marianum</i> (L.) Gaertn.] Improvement

Abstract

Milk thistle [Silybum marianum (L.) Gaertn.] is an important medicinal-industrial plant. The medicinal compounds of milk thistle are derived from its seeds. The plant is commercially cultivated for the production of silymarin. Cultivation offers the opportunity to optimise achene yield and silymarin content. Furthermore, efforts should be made to develop new cultivars. The main objective of milk thistle breeding is to develop high yielding cultivars with elevated silymarin content. There are few developed cultivars of milk thistle (e.g. Argintiu, Budakalaszi, Szibilla, Khoreslo, Babak Castle, Mirel, Silma and Silyb). Different genotypes of milk thistle have variable amount of silymarin e.g. a 'Royston' genotype is rich in silymarin (6-10%). Further progress can be made by using the genetic diversity available in abundance in different genotypes. The main concern of the breeder should be to increase the yield and silymarin contents of the seeds. Asynchronous flowering and seed shedding are also major problems in milk thistle cultivation. At the time of harvest, the plants have flower heads at all stages of development resulting non-uniform maturation of seeds. Therefore, a breeding effort in milk thistle should be planned to obtain plants with simultaneous flowering and reduced crop losses. The developed cultivar Argintiu is characterised by simultaneous seed maturation in flower heads. The wild populations, as valuable gene pools, could be exploited for the improvement of milk thistle crop.

Silymarin content and antioxidant activity of seeds of wild Silybum marianum populations growing in Greece

“…Similarly, Martin et al () also reported significant differences in silymarin content between years. The observed differences in silymarin concentration for the same populations during the research period were likely to have been due mainly to environmental conditions; in support of this, several authors have reported that silymarin content was affected by climatic conditions (Alemardan et al, ; Andrzejewska et al, ; Carrier, Crowe, Sokhansanj, Wahab, & Barl, ).…”

“…Milk thistle is mainly cultivated for silymarin production, but can be also be grown as an oilseed crop (Alemardan et al, ). In the present study, the oil content ranged between 24.65 and 31.10%, while the CV across all populations was only 5.7%.…”

“…Milk thistle is an important industrial plant cultivated in low acreage in several European countries like Poland and the Czech Republic (Andrzejewska et al, ; Růžičková, Fojtová, & Saučková, ). This species is normally cultivated for the production of silymarin (Alemardan, Karkanis, & Salehi, ; Andrzejewska et al, ), while the seeds and whole plant biomass can be used for oil and bioenergy production, respectively (Andrzejewska et al, ; Domínguez, Madejón, Madejón, & Diaz, ). Farmers use seeds from wild populations as propagation material for milk thistle cultivation, although a few cultivated varieties like Mirel and Silyb, in the Czech Republic, are available for commercial production (Růžičková et al, ).…”

CROSSING METHOD FOR THE FURTHER GENETIC IMPROVEMENT OF Silybum marianum (L.) Gaertn.

“…Despite the increasing interest in S. marianum as a multipurpose crop and its economic importance as an officinal species, only ten improved genotype/cultivars exist [Alemardan et al 2013]. The species is still marked by traits that are typical of non-domesticated plants: fruit scattering at maturity, asynchronous flowering, spiny leaves, variable yield stability and quality [Martinelli et al 2016].…”

“…As regard as both the plant morphology and the valuable fruit constituents, a wide phenotypic variability between accessions of different origins was observed but improved cultivars for these traits have not been released, yet [Ram et al 2005, Martinelli et al 2016. Hence, further genetic improvement is mandatory for the complete exploitation of milk thistle as a crop species [Alemardan et al 2013.…”