Family and Line Selection for Reduced Palmitate, Saturates, and Linolenate of Soybean

Abstract

Development of soybean [Glycine max (L.) Merr.] cultivars with reduced palmitate and stearate will lower the total saturated fatty ester content of the seed oil, and reduction of linolenate will improve its oxidative stability. The objective of this study was to compare the family and line methods of selection for reduced palmitate, palmitate + stearate (saturates), and linolenate in four populations segregating for the major alleles fap1 and fap3 for reduced palmitate or the fan1(A5) and fan2 for reduced linolenate. Four random F3‐derived lines from 21 F2 families from each population were evaluated in a plant‐row‐yield test in 1995 and replicated trials at four locations in 1996. For the family method, the mean palmitate, saturates, and linolenate of the four F3‐derived lines of each F2 family was used to identify families from which to select individual lines. For the line method, lines were selected without regard to the family structure. The fatty ester contents of the selected and unselected lines based on data from one environment were compared with their mean fatty ester contents in the other environments. The number of lines selected for each of the traits by the family method was less than for the line method in all populations. There was a greater percentage of lines incorrectly rejected by the family method than by the line method. For development of cultivars with reduced palmitate, saturates, and linolenate, breeding methods that rely on family performance would not be more effective or efficient than methods that ignore family structure.

Measurement of soybean fatty acids by near‐infrared spectroscopy: Linear and nonlinear calibration methods

“…A trained network is a function described by the number of hidden layers, the number of neurons at each layer (with their transfer functions), and a set of weights (including bias terms) assigned to links connecting the neurons. For example, the equation for a neural network with D inputs, K neurons in one hidden layer, and transfer (activation) function s in both output and hidden layers takes the form [2] where x i is ith input variable, w ij is the weight of the connection from ith input to jth neuron of the hidden layer (number of w-weights is equal to D for each hidden layer neuron); v j is the weight of the connection from jth neuron of the hidden layer tô output neuron (number of v-weights is equal to K); b j is bias of jth neuron of the hidden layer; b 0 is bias of the output neuron; s 1 and s 2 are functions defined, for example, as [3] The main limiting factor of this method is a sufficient number of training samples. More complicated networks require more training examples to perform adequately during prediction.…”

“…Reduction of levels of PUFA (particularly linolenic acid) and increase of oleic acid concentration improves oxidative stability of soybean oil during storage and processing. This avoids the hydrogenation process that results in increased concentrations of unhealthy trans-FA (2,3). In contrast, soybean varieties with high levels of saturated FA (palmitic and stearic) can be important for production of margarine and shortening (4,5).…”

Molecular markers associated with linolenic acid content in soybean

“…The development of an integrated molecular map is a major contribution that will enhance genetic gains (16). RFLP markers associated with 18:3 already have been placed on the soybean linkage map (6,12), but modern soybean breeders now utilize SSR markers to expedite selections because of the high level of polymorphism and general ease of use and interpretation of SSR markers. The two SSR markers identified here flank a 10-cM interval containing a major gene governing 18:3 content (Fig.…”

“…Byrum et al (9) suggested that the low-18:3 phenotype obtained with the Fan locus in soybean (A5) was the result of a mutation in the microsomal ω-3 linoleate desaturase gene, which mapped to linkage group B2, and in the plastid desaturase ω-3 linoleate, which mapped to linkage group G. From the literature, it appears that the heritability of 18:3 can be low: h 2 = 0.10 to 0.47 (10), to moderately high: h 2 = 0.73 (11), depending on the lines used as parents in the cross. Expression of this phenotype may also be influenced by environmental factors (12). Therefore, identification of molecular markers closely associated with 18:3 should be of interest to facilitate gene transfer to high-yielding genotypes.…”

Measurement of fatty acids in whole soybeans with near infrared spectroscopy

“…Reduction of levels of polyunsaturated fatty acids (particularly linolenic acid) and increase of oleic fatty acid concentration improves oxidative stability of soybean oil during storage and processing. This, in turn, allows avoiding oil hydrogenation process that results in increased concentrations of unhealthy trans-fatty acids (1,2). On the other hand, soybean varieties with high levels of saturated fatty acids, palmitic and stearic acids, can be important for production of margarine and shortening (3).…”