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Segregation Data (segregation + data)
Selected AbstractsIdentification of RAPD markers linked to recessive genes conferring siliqua shatter resistance in Brassica rapaPLANT BREEDING, Issue 6 2003O. Mongkolporn Abstract Shattering of siliquae causes significant seed loss in canola (Brassica napus) production worldwide. There is little genetic variation for resistance to shatter in canola and, hence, the trait has been studied in B. rapa. Previous studies have shown two randomly segregating recessive genes to be responsible for shatter resistance. Three random amplified polymorphic DNA markers were identified as being linked to shatter resistance using bulked segregant analysis in a F3B. rapa population. The population was derived from a cross between a shatter-susceptible Canadian cultivar and a shatter-resistant Indian line. Of the three markers, RAC-3900 and RX-71000 were linked to recessive sh1 and sh2 alleles, and SAC-201300 was linked to both dominant Sh1 and Sh2 alleles. The common marker for the dominant wild-type allele for the two loci was explained to have resulted from duplication of an original locus and the associated markers through chromosome duplication and rearrangements in the process of evolution of the modern B. rapa from its progenitor that had a lower number of chromosomes. Segregation data from double heterozygous F3 families, although limited, indicated the markers were not linked to each other and provided further evidence for the duplication hypothesis. [source] Chromosomal localization of five mutant genes in rice, Oryza sativa, using primary trisomicsPLANT BREEDING, Issue 1 2000A. C. Sanchez Abstract The chromosomal locations of five mutant genes in rice were determined by crossing the marker stocks with the 12 primary trisomics. Genetic segregation of each gene was studied in the F2 or backcross populations. Out of the 60 possible cross combinations, 43 F2 or BC1 populations were studied. Segregation data indicated that spl11 was located on chromosome 12 while wp2 and eg2(t) were located on chromosome 6. The genes v12(t) and Bc6 were located on chromosomes 8 and 9, respectively, which are sparsely populated with genetic markers. [source] Evaluation of common wheat cultivars for tan spot resistance and chromosomal location of a resistance gene in the cultivar ,Salamouni'PLANT BREEDING, Issue 4 2006W. Tadesse Abstract A total of 50 wheat (Triticum aestivum L.) cultivars were evaluated for resistance to tan spot, using Pyrenophora tritici-repentis race 1 and race 5 isolates. The cultivars ,Salamouni', ,Red Chief', ,Dashen', ,Empire' and ,Armada' were resistant to isolate ASC1a (race 1), whereas 76% of the cultivars were susceptible. Chi-squared analysis of the F2 segregation data of hybrids between 20 monosomic lines of the wheat cultivar ,Chinese Spring' and the resistant cultivar ,Salamouni' revealed that tan spot resistance in ,Salamouni' was controlled by a single recessive gene located on chromosome 3A. This gene is designated tsn4. The resistant cultivars identified in this study are recommended for use in breeding programmes to improve tan spot resistance in common wheat. [source] A SNP/microsatellite genetic linkage map of the Atlantic cod (Gadus morhua)ANIMAL GENETICS, Issue 6 2009T. Moen Summary A first genetic linkage map of the Atlantic cod (Gadus morhua) was produced, based on segregation data from 12 full-sib families of Norwegian origin. The map contained 174 single nucleotide polymorphism markers and 33 microsatellites, distributed on 25 linkage groups and had a length of 1225 cM. A significant difference in recombination rates between sexes was found, the average ratio of female:male recombination rates being 1.78 ± 1.62 (SD). [source] | ||||||||||