(38(4):405-411)Evaluation of Mass Selection by Seed Size in Bulk Soybean Populations

為配合大粒高產之育種目標，本試驗將HL-1×P58及KS8×T83-1兩雜交組合F3世代收穫之大豆種子，各別依粒型大小分羣，再評估各羣F4世代植株農藝性狀，探討簡便、易行之粒型混合選種法施行效果，結果顯示選拔大粒型種子可顯著提高族羣平均百粒重，對於產量、株高、及植株乾重等影響，則因不同雜交組合而異。不同粒型後裔族羣具有相近百粒重變異範圍，及百粒重與其他性狀間之遺傳相關特性之維持，推測無論直接對粒型或間接對產量等其他性狀之改良，另一循環世代之粒型混合選種仍有採行價值。 Two F3:4 populations, i. e. HL-1×P58 and KS8×T83-1 hybrid combinations, were evaluated for response of mass selection for seed size in soybeans. Large seeds derived lines had significantly higher seed weight (g/100-seed) than that of medium and small seeds derived lines indicated that mass selection for seed size in bulk populations was effective. Large seeds derived lines had significantly high seed yield, total dry weight of plant, and plant height than those of small seeds derived lines only found in KS8×T83-1 hybrid combination. With similar variation of seed weight and no significant difference among correlation coefficients between seed weight and other characters of various seed size derived lines, it is suggests that direct selection for seed size (in both hybrid populations) and indirect selection for seed yield, total dry weight of plant, and plant height (only in KS8×T83-1 hybrid combination) could be available in the next cycle of selection