Identification Of Allelism And GA₃-sensitivvity Of Foxtail Millet Dwarf Mutaitons

Utilization of dwarf genes was the key factor to increase lodging resistance and grain yield in wheat and rice,and systematic research on dwarf materials of many crops were carried out worldwide.However,the detailed study of dwarf materials of foxtail millet was rarely reported,which severely restricts the application of dwarf foxtail millet genes in breeding.The main goal of this paper was to identify allelism and gibberellin-sensitivity of foxtail millet materials collected.(1) Allelism detection of dwarf foxtail millet genes.Using half diallel cross design, crosses were made and 58 ridized combinations were obtained,of which 45 nonallelic combinations,7 allelic combinations,6 allelic combinations or parents had dominant dwarf gene combinations.Among the 47 dwarf foxtail millet varieties determined,33 varieties had recessive dwarf gene,the others were undetermined.Chiai 9,1066A and Aifeng 1 had recessive dwarf gene combinations.Moreover,Chuang 19-11 and Yanai 2,Ai88 and Anai 13,Kuanjiu and Aixie 1,Honggu 1 and Huzaogu 1 had allelic recessive dwarf gene.(2) Identification of gibberellin-sensitivity of foxtail millet dwarf genes.Dwarf mutants could be divided into gibberellin-insensitive and gibberellin-sensitive,so we identified the gibberellin-sensitivity of 48 foxtail millet dwarf mutants.The result shows: Seedling length of 46 samples were gibberellin-sensitive,the other two 84133chunhe and Xianai were gibberellin-insensitive.Also,gibberellin-sensitivity exhibited diversity in different organs of different varieties.Such as leaf length of Aifengl,Daqingjie and Yanai2 was gibberellin-insensitive,but their mesocotyl coleoptiles and root length were gibberellin-sensitive;coleoptiles of Ai88 was gibberellin-insensitive,but its leaf length, mesocotyl and root length were gibberellin-sensitive.It suggests that different dwarf materials may carry different dwarf genes and they have a different mechanism.All organs of the two gibberellin-insensitive varieties 84133chunhe and Xianai were gibberellin-insensitive in the seedling stage,which was similar to wheat varieties containing Rht-D1 and Rht-D1b genes.Mesocotyl was the critical organ to identify the gibberellin-sensitivity of dwarf foxtail millet,the suitable concentration of GA₃ was 30-50ppm.(3) Detection of the origin mechanism of high clum individuals in dwarf foxtail millet lines with ISSR technique.Using 12 ISSR primers,genetic variation of 35 high clum individuals from 14 dwarf foxtail millet lines were studied and compared with their original lines.The NTSYS2.1 cluster analysis indicated that most of those individual plants were outcross hybrids,it shows that foxtail millet was not a strictly self pollination species. F₂ generation of Anai8-Gao-2 had not segregation of populations characters,and the molecular identification shows that it had onlyl different band with its original Anai8,so it could be a reverse mutation of Anai8 and which need further experiment to proof.(4) Clone of Foxtail millet GAI gene.The GAI gene sequence of Zhaogul and 84133chunhe which obtained by the PCR method was identical,and so its dwarf mechanism need more work to mine.According to NCBI-BLAST,the sequence of Foxtail millet GAI gene was highly homology with maize's dwarf8 gene and Saccharum officinarum GAI gene.