Research notes: Evidence for linkage of G with one of the B loci in soybeans

In 1963, Tang and Li reported on a study of a cross, Glycine max x G. formosana (G. formosana = G. soja), in which the inheritance of a number of qualitative traits was determined. This paper is a reinterpretation of a portion of their data. Among the genes segregating in the cross were the following: i^i/i: restriction of dark seedcoat pigments to hilum/self-dark seed G/g: green seedcoat/yellow seedcoat (obscured in ii genotypes) B2,B3/b2, b3 : two of the three complementary factors for bloom on seedcoat; in the cross studied, both parents were B1B1, so that segregation at the other two loci produced F2 ratios of 9 bloom : 7 smooth

Research Notes: A new recurrent selection scheme incorporating genetic male sterility

The use of genetic male sterility to facilitate recurrent selection in soybeans has been discussed by Brim and Stuber (1973), Fehr and Ortiz (1975), Kenworthy and Brim (1979) and Brim and Burton (1979). A problem with the selection schemes that have been presented is the occurrence of male- sterile segregates in the yield-test plots and the consequent reduction of precision in measuring yield. In the proposed scheme (Table 1), male sterility is employed to recombine selected lines, but tested material consists of homozygous fertile plants

Research Notes: Epistasis and soybean breeding

Epistasis, or non-allelic interaction, may be of considerable importance in the inheritance of quantitative traits in soybeans . Hanson and Weber (1962) and Hanson et al. (1967) used a nested progeny design to partition the genetic variance among homozygous lines into additive and additive x additive (epistatic) components . In each of two populations, approximately 70% of the genetic variance for grain yield was attributable to epistasis

Hybrid Soybean Seed Production: Comparison of Three Methods

Improved methods to produce hybrid soybean [Glycine max (L.) Merr.] seed could augment several types of research. Two previously described methods, the traditional method and the dilution method, require insect-facilitated cross-pollination of ms ms nuclear male-sterile plants. The traditional method requires a substantial time investment during flowering to remove fertile siblings, and the dilution method requires a substantial amount of land and pollen-parent seed. Because time, land, and seed are limited, a more efficient method would be valuable. The cosegregation method was developed, utilizing close genetic linkage between the W1 locus and the Ms6 locus. The W1 ___, seedling has a purple hypocotyl; the w1 w1 seedling has a green hypocotyl. The ms6 ms6 plant is male sterile and female fertile. Approximately 97% of the purple-hypocotyl seedlings, W1 ___, in a line segregating for the w1 and ms6 alleles in coupling phase will he fertile, Ms6 ___, and can be removed as a pollen source at the first-trifoliolate stage. Our objective was to evaluate and compare the three methods of hybrid soybean seed production for seed yield, efficiency, and hybrid seed purity and quality. We used a randomized complete-block design (three replications per location, three locations, two years). The cosegregation method gave higher seed yield, better efficiency, and equal or better seed quality (percentage germination, 100-seed weight) than the other methods. Male-sterile plants yielded an average of 28.6 seeds plant−1 with the cosegregation method, 18.2 seeds plant−1 with the traditional method, and 9.5 seeds plant−1 with the dilution method. The cosegregation method will be useful in several research areas, including genetic control of complex traits, prediction of parental value, recurrent selection, and commercialization of hybrid soybean

The distribution and movement patterns of four woodland caribou herds in Quebec and Labrador

Recent studies of woodland caribou (Rangifer tarandus caribou) in northern Quebec and central Labrador have demonstrated similar patterns of seasonal movements and distribution among four herds. Aerial surveys and radio-telemetry indicated that animals occupied forest-wetland habitat at densities of 0.03 caribou km2, or lower, for most of the year. Although females were widely dispersed at calving individuals demonstrated fidelity toward specific calving locations, in successive years. Caribou did not form large post-calving aggregations. Movement was greatest in the spring, prior to calving, and in the fall, during or immediately after rutting. Caribou were generally sedentary during summer and winter, although some moved relatively long distances to late-winter range. Although the herds occupy continuous range across Quebec and Labrador, our data indicate that the herds are largely discreete and should be managed individually