02226naa a2200265 a 450000100080000000500110000800800410001910000170006024500610007726000090013830000190014749000080016652015410017465000130171565000130172865000140174165000170175565000090177265300080178165300120178965300080180170000190180970000170182877301150184514529092004-10-27       1989    bl uuuu     u00u1 u    #d1 aGREEN, D. E.  aUtilization of physiological traits in soybean breeding.  c1989  ap.988-993. t.2  vt.2  aThe objective of our cooperative research project, active since 1967, is to relate physiology to breeding soybeans. Traits investigates include morphological traits such as light penetration into the canopy, leaflet size, canopy height, canopy width, podded nodes on branches, and degree of stem termination; duration of seed filling; and leaflet photosynthetic rate. We find that lines that give the greatest seed yield increase, in response to narrowing row spacing, flower early, have an open and narrow canopy, are short, and have thick leaves (1968-73). Selection for small leaflets, open canopy, and short canopy in 1975 and 1977 resulted in seed yield increases of 3.7, 1.7, and 1.2%, respectively. Experiments conducted over 7 years, 1972-79, reveal that it ispossible to select determinate and semi-determinate lines that are shorter, lodge less, and yield equal to the indeterminate lines. Heritability estimates of leaflet photosynthetic rate, based on parental, F1, and F2 populations (1972) range from 36 to 54%. But, selection in the F2 and F3 generations failed to advance leaflet photosynthetic rate in succeeding generations. Selected F6 -derived lines that differed by 30% in leaf total photosynthesis (TPs) differed by 13% in the succeeding generation (1977/78). Selection for rapid Ps, as measured on single light-saturated leaflets, may not result in grater seed or dry matter yields in soybean (1979-82). Multiple train selection schemes (1983-88), utilizing selection for morphological traits and duration of seed  abreeding  agenetics  aGenética  aMelhoramento  aSoja  aEUA  aSoybean  aUSA1 aSHIBLES, R. M.1 aSUNDBERG, D.  tIn: CONFERENCIA MUNDIAL DE INVESTIGACION EN SOJA, 4., 1989, Buenos Aires. Actas... Buenos Aires: AASOJA, 1989.