HERITABILITY ESTIMATES AND RESPONSE TO SELECTION FOR THE PUNGENCY ANDSINGLE-CENTER TRAITS IN ONION

Heritabilities of the pungency and single center traits were estimated in onion breeding populations using selection response and half-sib f amily analyses. Pungency was determined indirectly by measuring enzyma tically produced pyruvic acid in individual bulbs. After one generatio n of selection, pungency was lowered by 8.1% and 8.9% in the populatio ns 90-61-1 and 89-69-8, respectively, and realized heritabilities of 0 .21 and 0.51 were estimated. Selection had no effect in lowering the p ungency of population 90-62. Heritability estimates calculated through half-sib progeny analysis were 0.53, 0.48, and 0.25 for pungency in t he populations 90-61-1, 90-62 and 89-69-8, respectively. The number of single centered onions was increased by 19% and 22% in populations 90 -62 and 89-69-8, respectively, after one generation of selection, and the realized heritability estimates were 0.37 and 0.34, respectively.