SIMULTANEOUS SELECTION IS EFFECTIVE IN INCREASING BETALAIN PIGMENT CONCENTRATION BUT NOT TOTAL DISSOLVED SOLIDS IN RED BEET

Betalain pigments, composed of the red-violet betacyanins (BC) and the yellow betaxanthins (BX), provide an excellent natural alternative to synthetic red dyes, The objective of this investigation was to evalua te eight cycles of recurrent selection in two red beet (Beta vulgaris L,) populations selected for high total betalain pigment concentration and both high (HPHS) and low (HPLS) total dissolved solids (TDS), Rem nant seed was planted in a randomized complete block design in replica ted trials at two locations in 1994, Beet roots were sampled at harves t for concentrations of BC, EX, and TDS, Highly significant difference s among cycles for BC, EX, BC:BX, total pigment, and TDS were observed , Average gains per cycle were 13.15 and 4.06 mg per 100 g fresh weigh t for BC and EX in HPHS, and 7.59 and 2.61 mg per 100 g fresh weight f or BC and EX in HPLS, respectively, Total pigment increased about 200% in both populations, Selection for low TDS was ineffective, while onl y a mild response was detected from selection for high TDS, Since beta lain pigments are formed following glycosylation of cyclodopa and beta lamic acid, sugar molecules are associated with pigment biosynthesis, Simultaneous selection for high pigment and low TDS may therefore be m etabolically incompatible, Our findings demonstrate betalain pigment c oncentration responds favorably to recurrent selection; however, a con comitant reduction in TDS is not a feasible selection goal.