Inheritance of R Locus Expressing Brown Hilum on Black Seed Coat in Soybean

Color is one of the phenotypic markers mostly used to study soybean (Glycine max L. Merr.) in the study of genetic, molecular and biochemical processes, due to their easy recognizability. The genetic control of several soybean natural variants has not been studied. The standard phenotype of R gene is black hilum on black seed. The genetic type T16 is the only occurrence with brown hilum on black seed coat and its genetic control was not described until now. The aim of this study is to understand the genetic control of seed coat and hilum color in the genetic types T16 and in the natural variants of Bragg, BR6 and BR13. T16 was combinined with Bragg P and BR13P (black seed color) and BR6M (brown seed color) and T236 (r-m). It was found that the genetic control of the brown hilum trait in black seed coat of the T16 genotype was controlled by two loci segregating independently and controlling the expression of the color of the hilum and the seed coat color. The expression of the brown hilum trait in black seed coat is dependent on locus T_, which controls pubescence color;therefore it occurs only in genotypes with tawny brown pubescence (T_), which caracterizes the pleiotropic effect of this locus on the trait hilum brown trait in black seed coat. The color of the hilum and the seed coat color belong to the same allelic sequence. No maternal effect was found in the expression of hilum brown trait in black seed coat.

Repeatability of Pre-Harvest Sprouting in Wheat

This study aimed to detect genotypic differences in the resistance to sprouting of wheat grains, evaluate the effectiveness of different methods for inducing sprouting and identify, using repeatability estimates, the minimum number of spikes necessary for the adequate evaluation of the percentage of grain sprouting in the spike in order to assist in the selection of superior genotypes in breeding programs. Spikes from four wheat cultivars (Frontana, IPR Catuara, Quartzo and BRS 220) were evaluated using three methods for inducing grain sprouting in the spike (water immersion, rainfall simulation and germination chamber). To determine the most efficient method, repeatability coefficients were estimated through analysis of variance, principal components analysis and structural analysis based on correlation and covariance matrices. The induction of sprouting by immersion in water was the most effective method for indicating genotypic differences and may be used in breeding programs for this purpose. The repeatability method based on the components of covariance was more efficient. A minimum of 11 spikes is required to make a high-reliability estimate of the percentage of sprouted grains in the spike.

Soybean Improvement for Lipoxygenase-free by Simple Sequence Repeat(SSR)Markers Selection

Beany flavor of soybean(Glycine max(L.)Merr.)is caused by oxidation of polyunsaturated fatty acids by the action of three lipoxygenases(LOX1,LOX2 and LOX3)present in mature seeds.The unpleasant flavor restricts human consumption of soybean products.This problem could be solved through genetic elimination of alleles that code these enzymes.Parental cultivars and two hybrid population were selected and analyzed using genetic markers for alleles locus,encoding L_(ox1),L_(ox2)and L_(ox3)free.The SSR marker Satt 212 confirmed the presence of the homozygous null-allele L_(x3)in the cultivar BRS 213,which were used for hybridization with BR 36.Heterozygote F1 hybrid plants and homozygous L_(x3)lines in F_(2)segregating populations were successfully identified.The SSR markers Sat090 and Sat417 were the most effective diagnostic markers among all SSR markers tested.Satt090 and Satt417 confirmed the presence of the homozygous L_(x2)null-allele in the parental cultivar BRS 213 by flanking L_(x2)loci at 3,00 and 2,77 cM,respectively.The presence of L_(x2)null allele in the F_(2)segregating populations between BRS 213 and BRS 155 was successfully identified with a selection efficiency of 98%and have great potential for further application in the Brazilian breeding program aimed at improving soybean seed quality.