Genetic Analysis of Sorghum Allelopathy

In sorghum, efforts are also being made to explore the biosynthetic pathway for the production of sorgoleone in root hair cells. Most of the work done is based on chemical analysis and there is very little information on genetic aspect of such characteristics. A diversity research set (SDRS) composed of 107 sorghum accessions from Asia and Africa regions was used. The intraspecific variations among sorghum accessions for allelopathic effect were assessed. Data was recorded on germinating lettuce seedlings for roots of 10 randomly selected seeds in 5 replications for each extract and 2 replications for each accession.

Genotyping of SDRS was done using 181 simple sequence repeats (SSRs) derived from previously reported maps. For genetic mapping, different models of association analysis were used to identify QTLs controlling allelopathic effects of sorghum. Several QTLs with different levels of effect were identified and the results will be shown later after finalizing the analysis. Among them four QTLs were identified for germination, including single locus in chromosomes 1 and 6 whereas, two loci in chromosome 2. Similarly two QTLs were identified for root length each on chromosome 9 and 10. We also developed a segregating population from a cross between two accessions with different allelopathic characteristics. The F₂ population was genotyped with SSR markers and F₃ progenies were phenotyped for screening the presence or absence of allelopathic characteristics using bioassay method. In this method also several QTLs were identified including some located in same regions of chromosomes as detected by association analysis.