Inheritance of Subcrown Internode Length in a Winter Barley Cross1

Abstract

The inheritance of subcrown internode length was studied in a controlled environment in a winter barley (Hordeum vulgare L.) cross between the cultivars NE62203 (C.I. 15542), with a short subcrown internode, and MO B2632 (MO B475/‘Tschermak’), with a long subcrown internode. Cultivars with short subcrown internodes and, therefore, deep crowns have been observed to show less winter injury than those with shallow crowns. Segregation patterns of the F2, F3, B1s, and B2s generations were discontinuous. In each generation, a distinct group of progeny occurred in the 0.0 to 0.5 cm class, suggesting that short subcrown internode length is determined primarily by a gene(s) with major effect. An analysis among generation means detected relatively large dominant gene effects in the direction of long subcrown internode length. Neither a 3:1 monogenic ratio nor a 15:1 digenic ratio were able to sufficiently explain the observed segregation pattern. Apparently, genes with smaller effects also influence the expression of subcrown internode length. A heritability (narrow sense) estimate of 86.9% for subcrown internode length was obtained. Realized genetic advance for short subcrown internode length at 10% intensity of selection was 2.7 cm, or 77.1% of the F3 population mean. Because of the high heritability and presence of a gene(s) with major effect determining short subcrown internode length, F2 selection for short subcrown internode length should be effective.