The experiment was conducted to study the effect of gamma-ray irradiation on the high concentration thidiazuron (TDZ) produced buds. In vitro buds were irradiated with different gamma-ray doses. Akihime cultivar ('Akihime') was irradiated with the doses of 0, 30, 80, 130, 180, and 230 Gy while 'DNKW001 accession' ('DNKW001') was exposed to the doses of 0, 30, 80, 130, 180, 230, 280, 300 and 325 Gy and similar doses of gamma rays + EMS 7M (GRE) treatments. Survival rate and plantlet performance of DNKW001 in gamma ray + EMS 7M treatment declined profoundly with increasing doses and LD 50 was lower (104 Gy) than LD 50 in gamma ray irradiation (177 Gy) alone. Variants of plantlets were detected in pre (white streaked leaf and bigger petiole with distorted leaf) and post acclimations (dwarf, dwarf-necrosis, variegated, dark-rigid-thick leaf, rumpled leaf, heart shape-bright red fruit). Hexadecaploid of Akihime and pentadecaploid, 13x + 4 chormosome, and diplodecaploid of DNKW001 were discovered sturdy plants with thicker leaf and bigger pollen than octoploid plant, while the monosomic octoploid performed a dwarf plant. Outstanding variants based on fruit weight, total soluble solid content and color in plot of Principle Component Analysis (PCA) were selected and proved as mutants in DNA level. Gamma ray irradiation + EMS was more effective to generate more type and magnitude of variants. Irradiation dose less than 130 Gy was ample for generating variant plants of strawberry.

0 . E. 1989. The effects of defective Suppressor-mutator insertions on the expression of a Bronze-1 allele in maize. Genome, 31: 980-986. Molecular and biochemical analyses of the maize transposable element mutant bronze-m13, which resulted from the insertion of a defective Suppressor-mutator element in an exon of a Bronze-1 allele, and of changes of state derived from bronze-m13 by internal deletions within the element have revealed how these mutant alleles condition a nonmutant phenotype in the absence of a trans-active Suppressor-mutator. The transposable element insertions are all in the same position, 38 base pairs 3' to the single intron present in the bz locus. The insertions are transcribed with the gene, and the pre-rnRNAs of bronze-m13 and CSl, CS5, CS6, and CS12 are then spliced using the intron donor splice site and either one of two acceptor splice sites in the defective Suppressor-mutator element. Only one of these two messages is translated to yield a functional enzyme. The pre-mRNA of CS9 is spliced only in the reaction that gives a translatable message since the pre-mRNA lacks the alternate acceptor splice site. The splicing reactions are detailed and related to the very different amounts of enzymatic activity produced by these alleles. The presence of an antisense message in CS12 plants to the defective Suppressor-mutator sequence transcribed with the bronze locus is also discussed.Key words: maize transposable element, Suppressor-mutator, splicing.KIM, H. Y., RABOY, V., SCHIEFELBEIN, J. W., et NELSON, 0 . E. 1989. The effects of defective Suppressor-mutator insertions on the expression of a Bronze-1 allele in maize. Genome, 31 : 980-986. Un klkment mutant transposable chez le mays, le bronze-13, rksulte de l'insertion d'un klkment suppresseur-mutateur imparfait dans un exon d'un allele de Bronze-1 et de changements d'ktats, dkrivks du bronze-m13, par des dklktions internes dans cet klkment. Des analyses biochimiques et mol6culaires ont rkvklk comment ces allkles mutants conditionnent un phknotype non mutant en l'absence d'un suppresseur-mutateur trans-actif. Toutes les insertions de l'klkment transposable se font dans une mtme position, soit 38 pairs de bases 3' en direction de l'unique intron prksent dans le locus bz. Les insertions sont transcrites avec le gkne et les pr6ARNm de bronze-m13 et de CSl, CS5, CS6 et CS12 sont alors interreliks dans le site d'attachement de l'intron donneur et dans l'un ou l'autre des deux sites accepteurs d'attachement de l'klkment suppresseur-mutateur imparfait. Un seul de ces deux messages est transcrit et produit une enzyme fonctionnelle. Le pr6-ARNm de CS9 n'est inskrk que dans la rkaction qui donne un message traductible, puisqu'il n'a pas de site alternatif accepteur d'insertion. Les rkactions d'insertion ou d'attachement sont dktaillkes et relikes aux quantitks trks diffkrentes d'activitks enzymatiques produites par ces allkles. La prksence d'un message inversk (antisense) chez les plantes CS12, en direction de la skquence suppresseur-mutateur imparfaite ...