Allelism Test between Crosses of High-O/L x High-O/L and Very High-O/L x Very High-O/L Peanut Genotypes

ABSTRACT Crosses were made between High-O/L x High-O/L and between Very High-O/L x Very High-O/L peanut genotypes. The High-O/L parental genotypes were F435-OL-2 and ‘Flavor Runner 458’ and ranged between 20 and 40:1 oleic (O) to linoleic (L) fatty acid methyl ester ratio. The Very High-O/L parental cultivars were ‘Georgia Hi-O/L' and ‘Georgia-11J' and consistently had O/L ratios ≥40:1 over four years at the Tifton, Georgia location when grown under maximum-input production practices with irrigation. F1 plants from the High-O/L x High-O/L cross combination had an average O/L ratio of 32.5:1; whereas, the F1 plants from the Very High-O/L x Very High-O/L crosses had an average O/L ratio of 50:1. Average O/L ratios of both F2 and F3 generation progeny also had similar O/L ratios within High-O/L x High-O/L and Very High-O/L x Very High-O/L crosses. The results from these test crosses suggest that there are at least two different high-oleic genotypes possibly associated with either multiple alleles or modifier genes.

Genetic analysis and molecular markers associated with multi-gynoecia (Mg) gene in Trigrain whea

Trigrain wheat normally produces up to three gynoecia in a single floret and forms three close-set grains. The gene conferring the multi grain phenotype was earlier designated Mg, the multiple gynoecia gene. Different genetic patterns controlling this trait have been reported. In the present work we studied the inheritance of the three grains trait and identified simple sequence repeats (SSR) markers linked to the Mg gene. Segregation analysis in the cross IGDB-TW (trigrain wheat)/Chinese Spring confirmed that a single dominant gene controlled the three grains trait. An allelism test showed that the same gene controlled the trigrain trait in line Trigrain-Yin 1. A total of 339 microsatellite markers were tested for polymorphism by bulked segregation analysis (BSA) in an F2 population. Six microsatellite markers, Xcfd233, Xgdm6, Xgdm87, Xgwm311, Xgwm349 and Xgwm539, on chromosome 2DL, were linked to Mg. Using the CS 2D deletion lines, Mg gene was localized to the distal region of chromosome 2DL. The microsatellite markers identified in this study have the potential for further mapping and map-based cloning of the gene.Key words: Simple sequence repeats, physical mapping, trigrain wheat

The frequency of allelic lethals and complementation maps in natural populations of drosophila melanogaster from Mexico

Departing from a previous study on the genetic loads affecting the second chromosome of Drosophila melanogaster in four natural populations, 171 lethal chromosomes were recovered and maintained as a balanced stocks in the condition Cy L / 1 (l=lethal); of those lethais 24 correspond to population A, 50 to populations B and C and 47 to population D. later on an intra-population allelism test for the four populations was performed for each one. A total of 3807 inter lethal crosses were done yielding a total of i 10 allelic combinations, from them the respective percentage of allelism for each population was calculated and they are as follow: 3.98 % for population A, 1.80 % for population B, 3.67 % for population C and 2.96 % for population D. the observed values for the frequency of allelism in these populations are not significantly different from those reported by other authors in similar studies in natural and/or experimental populations. Beside these values the frequency for singles, doubles, triplets and even quadruplets present in each population were determined, they shown the presence of various complementation maps due to the clustering of few different lethals: also a large complementation map formed by a large cluster involving the presence of 26 different lethals found in population D all of them combined constituting a single unit was found.

Inheritance of the Anasazi Pattern of Partly Colored Seedcoats in Common Bean

Inheritance of Anasazi pattern of partly colored seedcoats in common bean (Phaseolus vulgaris L.) was studied in a genetic stock t ana B V Anasazi BC3 5-593, whose Anasazi pattern is derived from Plant Introduction (PI) 451802. Line 5-593 is a determinate, Florida dry bean breeding line (with small black seeds) used as the recurrent parent in the development of many genetic stocks. The F2 from the cross t ana B V Anasazi BC3 5-593 × t z virgarcus BC3 5-593 segregated for two nonparental phenotypic classes and was consistent with the hypothesis that a single recessive gene, with tentative symbol ana, produces the Anasazi pattern with t Z ana and a new partly colored pattern Anabip with t z ana. Thus, the Anasazi factor is not an allele at the Z locus. Analysis of 57 random F3 progenies from the cross t ana B V Anasazi BC3 5-593 × t z virgarcus BC3 5-593 supported a genetic model where: 1) with t Z the Anasazi phenotype is controlled by a single recessive gene ana, i.e., genotype t Z ana, 2) the Anabip phenotype has the genotype t z ana, and 3) t Z/z ana produces a restricted Anasazi pattern. The allelism test cross t z ana Anabip BC3 5-593 × t z lers white BC3 5-593 produced complementation in the F2, demonstrating nonallelism of Ana (actually Bip) with the L locus. The allelism test cross t z ana Anabip BC3 5-593 × t z bip bipunctata BC3 5-593 failed to show complementation in F1 and F2, demonstrating allelism of Ana with the Bip locus. Using bulk segregant analysis, molecular markers linked in coupling to the Ana (OM9200, 5.4 cM) and Bip (OJ17700, 6.0 cM) genes were discovered. Allelism was also suggested by the result that the same linkage distance and recombination pattern were observed when the Ana marker was used to score the bipunctata population. We propose the gene symbol bipana for the recessive allele at the Bip locus that produces Anasazi pattern with genotype t Z bipana and the Anabip pattern with genotype t z bipana. Although bipana and bip are both recessive to Bip, their interactions with the Z locus are extraordinarily different. The pattern restrictive power of bipana expresses partly colored pattern with t Z, whereas bip requires t z to express partly colored pattern.