Genetic Analysis And Preliminary Gene Mapping Of A Plant Height Mutant In Maize

Height was an important agronomic trait of maize. A maize dwarf mutant was got and the gene was mapped by map-based cloning, the results were as follows:1. Discovery of a new dominant dwarf mutant in maize and its preliminary study.A dwarf mutant 52333 was identified from CL1077. the plant was about 120 centimeters tall, it was very low, and it could have homozygote.2. Genetic analysis of plant height.Based on the analysis of the population variations of plant height in hybrids including P1, P2, F1, F2, BC1 (backcrossed to dwarf parent) and BC2 (backcrossed to tall parents) derived from five cross combinations between a dwarf mutant of 52333 and tall inbreed lines: the F1 individuals were as short as the short parents, and the plant height of reciprocal crosses had no remarkable differences, and the segregation of the F2 generation appeared to be 3 short: 1 tall, the dwarf F1 hybrids with the new dwarf gene were backcrossed with the tall inbred lines, the approximately segregation ratio of BC1 populations was 1short:1tall, and the offsprings derived from the combination of F1 with 52333, were all dwarf plants, so the dwarfing effect of the new gene was confirmed, indicated that the dwarf trait of 52333 was controlled by one dominant gene and its expression could not be affected by cytoplasm.3. sensitivity to gibberellin of the mutant.Soak and sprout Seeds of the F1 progenies which were derived from the crosses between dwarf mutant(52333) and the inbred lines(382-2 and 178) and the pure dominant mutant 52333, the seeds were placed in refrigerator with 4℃for two days until the coleoptile growed out, then the bourgeon seeds were planted in four plates with silver sands. Each plate has 25 young plants, which treated with 0ppm GA3,30ppm GA3,40ppm GA3 and 50ppm GA3 each day, and the plant height measured in two and three leafage proved that the dwarf gene was sensitive to gibberellin,it was different from the dominant genes which have been discovered before, so the dwarf gene may be a new gene.4. The mapping of the dwarf gene.A cross between dwarf mutant 52333 and zheng58 was made,Plant height was found that there were twe kinds of plants,dwarf and tall.The plant number of tall plants was 500, the tall plants were used for mapping, the dwarf gene Dt was linked with p-umc1077, the genetic distances between Dt and p-umc1077was 4.56Cm. In order to establish the fine location of the dwarf gene Dt, 87 SSR markers on maize chromosome 10 were used for mapping, the result showed that Dt was linked with 13 SSR markers, The genetic distances between Dt and p-umc1453 as well as p-umc1678 were 4.43cM and 5.26cM 3.87cM, respectively,Dt was located on chromosome 10 preliminary...