Variability of crude protein and carotene contents and their relations with other characters in bromegrass, bromus inermis Leyss

A study of variability in crude protein content, carotene content, yield, color, and selected morphological characters was made for spaced plants of 175 lines from 25 unrelated first generation inbred families of bromegrass. The characteristics of the top growth were studied during the second and third years after transplanting. The principal stage of growth investigated was the "early pasture stage" which was just before the initial period of rapid stem elongation in early May. Selected plants were studied at anthesis or hay stage. A split plot design with three replications was employed. Analyses of variations in yield, moisture, protein, and carotene contents were made by means of analyses of variance. All specific comparisons made were with use of correlation coefficients. In the second year significant differences in yield at anthesis were found among plants within 11 of the 25 families. There were highly significant differences in yield among the families. Analyses of moisture content showed no significant differences among plants at any stage studied. Carotene content varied significantly among plants in 6 of 17 families analyzed at the early pasture stage of the third year. Highly significant differences in carotene content were found among families. Carotene content at the early pasture stage was positively correlated to a high degree with color and protein content at the same early stage. Protein content at the early pasture stage was found to be significantly different among plants of 20 families in the second year and among plants of 22 families in the third year. Highly significant differences among families in protein content occurred in both years at the early stage. Protein differences were highly significant among plants at an intermediate boot stage of growth in the second year and among 50 selected plants at anthesis in both the second and third years. Protein contents at the early growth stages of the second and third years were positively correlated to a very high degree (+.89). Protein content at anthesis was positively associated to a high degree with protein content at the early stage of the second and third years. Protein content was related more closely to a degree of green color at the early stage and anthesis than to any other morphological character studied. Protein contents at anthesis stages of the second and the third year were very closely related. It was concluded that selection of plants with high protein content by using a morphological character as an indicator would not be practical. Direct testing of protein content during early growth stages, of lines of bromegrass in advanced trials, is proposed.