Inheritance of Bean Seed Globulin Content and its Relationship to Protein Content and Quality1
- Martha A. Mutschler and
- F. A. Bliss2
Globulin-1 (G1) protein, the major storage protein fraction of common bean, Phaseolus vulgaris L., was measured in mature seed using rocket immunoelectrophoresis. Percentage total protein was measured by infrared reflectance. Heritability estimates were calculated for the protein traits and seed yield, and correlations between traits were determined using parental, F2 and F3 populations.
Among the six parents grown in the field in 1977, ‘Endogava Z.N.’ had the highest percentage protein (27.8% protein), while PI 229815 produced the most G1 protein (136.5 mg G1/g flour). Both were low yielding, producing 12 and 13 g seed/plant compared to the highest yielding parent, ‘Bonita’ that produced 66 g seed/plant. Bonita showed the most favorable combination of traits, with levels of 24% protein and 108 mg G1/g flour, in addition to high yield. ‘Swedish Brown’ and WI 74-2047 had the lowest levels of total protein, (17.4 and 18.5%, respectively) as well as G1 protein (75 and 61 mg/g flour, respectively).
Analyses of 5 of the 15 F2 populations derived from crosses among the six parents were presented in detail. Inheritance of both percentage protein and mg/g flour was quantitative with broad sense heritability estimates ranging from 0.19 to 0.65 and 0.37 to 0.95, respectively. Narrow sense heritability estimates ranged from 0.59 to 0.86 and 0.43 to 0.74 for percentage protein and mg G1/g flour, respectively in four populations.
Mean F2 values of populations resulting from crosses between parents that differed widely for protein amounts were usually intermediate between the two parents. The average values of the five F2 populations resulting from one common parent produced rankings similar to those based on parental values for percentage protein and mg G1/g flour.
Moderate positive correlations between mg G1/g flour and percentage protein were observed in F2 and F3 populations. There was no correlation between yield and mg G1/g flour and low negative correlation between yield and percentage protein. No obvious consistent relationship between available methionine and G1 content was seen, perhaps because of variation in other constituent fractions or the confounding effects of seed tannins. Implications of genetic manipulation of protein fractions and total protein on protein quality improvement are discussed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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