Evaluation and Stability of Red and White Trifolium Species for Nutritional Quality in a Mediterranean Environment

It is generally recognized that clovers represent a major nutrient used in ruminants’ diets due to their composition, which is high in protein content and low in fiber content. Investigating the nutritional quality of red and white clover genotypes, and classifying the genetic materials according to their primary quality attributes were the main goals of the current study. During a two-year experiment, we assessed their performance stability. Twelve red clover (Trifolium pratense L.) and twelve white clover (Trifolium repens L.) genetic materials were cultivated in a randomized complete block experimental design. Crude protein (CP%), acid detergent fiber (ADF%) and neutral detergent fiber (NDF%) concentrations were measured, and the relative feed value (RFV) was calculated using the estimates of digestible dry matter (DDM%) and potential dry matter intake (DMI% of body weight) of the forage. The average CP% content for white clover varied between 17.18% (REP-4) and 20.55% (REP-9) during the two years of testing. Regarding the red clover, the populations PRA-4, PRA-3, PRA-5, and PRA-10 exhibited the highest CP% content (19.98%) and the lowest ADF% (less than 29%). Although the variation was stable across the years, the profile of this variation of CP, ADF, and NDF for each clover species differs. The CP% was related negatively to ADF% and thus positively to DDM in both species but not with the same allocation, forming different clusters. PRA-3 and PRA-4 for the red clover and REP-5 for the white clover genetic materials exhibited characteristics belonging to the other species studied regarding their content in protein and fiber. Because of their relationship, CP and DDM could be improved simultaneously by breeders. This study revealed that ROZETA and PRA-4 were more stable genetic materials in red clover, and GRASSLANDS HUIA, RIVENDEL, and REP-5 in white clover.