Date of Award

1999

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Plant, Environmental Management and Soil Sciences

First Advisor

Manjit S. Kang

Abstract

Genes that may confer resistance to diseases, tolerance to plant stress, good stalk quality, high yield potential and/or other desirable attributes are important. The leafy gene (Lfy1Lfy1) discovered in 1971 in maize (Zea mays L.) is known to produce much higher yields in hybrids that possess it. These hybrids suffer much less stalk lodging than those with the non-leafy (lfy1 lfy1) gene. The location of the leafy gene to a chromosome arm could facilitate both its transfer from one genotype to another and its use in linkage studies and aid in completing the maize linkage map. The purpose of this investigation was to identify the chromosome arm that carries the leafy gene by using waxy-marked reciprocal translocations. Inbred lines 371 and 957 containing the Lfy gene were crossed with translocation stocks and subsequently test crosses were produced. An examination of the probability values for these test-crosses revealed that leafy gene in both inbreds is located in the long arm of chromosome 4. The gene, nsf1, conditions susceptibility to nicosulfuron (Accent) herbicide in maize and it was discovered in 1992. Pinpointing its location to a specific chromosome arm could facilitate its use as a genetic marker in linkage studies and in other genetic experiments. B-A chromosomal translocations provide an efficient means of mapping recessive genes. The objective was to identify the chromosome arm that carries the nsf1 gene via B-A translocations. Fifteen homozygous B-A translocations that were resistant to nicosulfuron were each crossed as male parents to a susceptible inbred line (L668). The F1 seeds were field and greenhouse grown in 1997 and 1998. Data obtained after treating F1 progeny with nicosulfuron and genetic analyses of these data revealed that the nsf1 gene occupies a locus on the short arm of chromosome 7.

ISBN

9780599372597

Pages

57

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