Inheritance and linkage relationships of genes conditioning hullessness, multiflorous spikelet, and giantism in oat (Avena sativa L.)

Abstract

A study was conducted to determine the number of genes, type of gene action, and linkage relationships of the factors controlling the expression of hullessness, multiflorous spikelet and giantism in oat (Avena sativa L. var. PI 546363). The results showed that giantism was governed by a recessive gene, which in a homozygous (gi-3/gi-3) condition may have an epistatic effect on several other loci including those controlling the expression of plant height; length, width, and thickness of leaves; culm diameter; number of internodes; panicle size; pedicle length; and number of days to anthesis and to maturity. The results also indicated monogenic inheritance for hull and spikelet characteristics. Hullessness (N-1/_) was dominant over hulledness (n-1/n-1), and multiflorous spikelet (Mf-1/-) was partially dominant over normal spikelet (mf-1/mf-1). Linkage was detected between the gi-3 locus controlling giantism, and the n-1 locus controlling hullessness; the recombination value was calculated to be 36.5 ± 0.8%. Linkage was also detected between the gi-3 gene and the Mf-1 locus conditioning multiflorous spikelet; the recombination value was 23.5 ± 0.4%. The N-1 gene appears to have an epistatic effect on the Mf-1 locus, and the recombination frequency between the two loci was 10.5 ± 0.6%. The gene order was gi-3, Mf-1, N-1. Key words: Oat, Avena sativa, genetics, giantism, hullessness, multiflorous spikelet