Publication Date:
2012-10-20
Description:
Background In this report we studied the genetic regulation of juvenile development of wildbarley introgression lines (S42ILs) under two contrasting hydroponic nitrogen (N)supplies. Ten shoot and root related traits were examined among 42 S42ILs and therecurrent parent ‘Scarlett’. The traits included tiller number, leafnumber, plant height, leaf and root length, leaf to root length ratio, shoots androot dry weight, shoot to root weight ratio, and chlorophyll content. Our aimswere (1) to test the suitability of a hydroponic system for early detection offavourable S42ILs, (2) to locate quantitative trait loci (QTL) that control theexamined traits, (3) to identify favourable wild barley alleles that improve traitperformances in regard to N treatment and, finally, (4) to validate the identifiedQTL through comparison with previously reported QTL originating from the sameparental cross. Results The phenotypic data were analysed in a mixed model association study to detectQTL. The post-hoc Dunnett test identified 28 S42ILs that revealed significant(P 〈 0.01) effects for at least one trait. Forty-three, 41 and 42S42ILs revealed effects across both N treatments, under low N and under high Ntreatment, respectively. Due to overlapping or flanking wild barley introgressionsof the S42ILs, these associations were summarised to 58 QTL. In total, 12 QTL ofthe hydroponic N study corresponded to QTL that were also detected in field trialswith adult plants of a similar S42IL set or of the original S42 population. Forinstance, S42IL-135, -136 and -137, revealed increasing Hsp effects fortiller number, leaf number, leaf length, plant height and leaf to root ratio onthe long arm of chromosome 7H. These QTL correspond to QTL for ears per plant andplant height that were previously detected in field trials conducted with the sameS42ILs or with the S42 population. Conclusion Our results suggest that the QTL we identified under hydroponic N cultivationpartly correspond to QTL detected in field experiments. Due to this finding,screening of plants in early developmental stages grown in a hydroponic system maybe a fast and cost effective method for early QTL detection and marker-assistedallelic selection, potentially speeding up elite barley breeding programs.
Electronic ISSN:
1471-2156
Topics:
Biology
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