Genetic mapping of a quantitative trait locus (QTL) that enhances the shoot differentiation rate in Hordeum vulgare L.

Abstract

A quantitative trait locus (QTL) controlling shoot differentiation from immature embryo callus was identified by linkage analysis with morphological and isozyme markers in barley, Hordeum vulgare L. Immature embryos were isolated from cvs 'Azumamugi' (difficult to differentiate), 'Kanto Nakate Gold' (easy to differentiate), their hybrids (F1) and a backcross population derived from a cross 'Azumamugi' x F1. The embryos were cultured in vitro for callus initiation and subsequent shoot differentiation. The shoot differentiation rate was closely associated with ear type (v locus), isocitrate dehydrogenase isozyme (Idh-2), and esterase isozyme (Est-11). These markers were found to reside in a chromosome segment of approximately 30cM on chromosome 2. Recombination frequency was 9.9% between v and a proposed QTL named "Shd1" (shoot differentiation), 11.5% between Idh-2 and Shd1, and 21.3% between Est-11 and Shd1. All data showed the Idh-2, v, Shdl and Est-11 loci to be arranged in this order from proximal to distal on the long arm of chromosome 2.

Identification of Quantitative Trait Loci (QTLs) Controlling Heading Time in the Population Generated from a Cross between Oriental and Occidental Barley Cultivars (<i>Hordeum vulgare</i> L.)

“…Sgh2 is a dominant spring growth habit gene located on chromosome 5HL (Takahashi and Yasuda 1956) and Kanto Nakate Gold harbors the Sgh2 gene, which induces earlier heading under non-vernalized conditions (Komatsuda et al 1993). In the present study, one major QTL was mapped in the Sgh2 region under all three conditions, and in the lines with the Kanto Nakate Gold allele (Sgh2) heading occurred consistently later under the three cultivation conditions (Table 2).…”

“…Azumamugi is a winter type (Sgh1/sgh2/sgh3) sixrowed cultivar and Kanto Nakate Gold is a spring type (sgh1/Sgh2/sgh3) two-rowed cultivar (Takahashi et al 1983, Komatsuda et al 1993. RILs (F 12 ) generated from the cross between Azumamugi and Kanto Nakate Gold have been developed by the single seed descent method.…”

Quantitative Trait Loci Controlling Agronomic Traits in Recombinant Inbred Lines from a Cross of Oriental- and Occidental-type Barley Cultivars

“…The two cultivars are polymorphic for the above-mentioned morphological and physiological traits (Komatsuda et al 1993). Azumamugi is a typical Japanese six-rowed cultivar with a winter growth habit produced from a cross between Japanese landraces ('Tochigi Sekitori 1' and 'Torano-o Sai 1').…”

Genetic Regulation of Gene Expression During Shoot Development in Arabidopsis

“…Variation in shoot regeneration can be troublesome especially when elite lines are difficult to regenerate. Shoot regeneration efficiency is a quantitative trait, and quantitative loci (QTL) associated with variation in shoot regeneration efficiency have been identified in Arabidopsis (Schiantarelli et al 2001) and other plants (Komatsuda et al 1993;Taguchi-Shiobara et al 1997;Holme et al 2004). Shoot regeneration QTL in Arabidopsis were identified in recombinant inbred lines (RIL) that differ in shoot regeneration efficiency (Lall et al 2004).…”