Some wild species of Oryza possess agronomi-cally useful traits such as disease/insect resis-tance and salt tolerance.However,the use ofwild Oryza species for rice improvement hasbeen hampered by the sexual incompatib...Some wild species of Oryza possess agronomi-cally useful traits such as disease/insect resis-tance and salt tolerance.However,the use ofwild Oryza species for rice improvement hasbeen hampered by the sexual incompatibility orsterility of hybrids obtained by conventionalmethods.We have used protoplast fusion as amethod to incorporate useful trait of wild O-ryza species into cultivated rice and~ obtainedsomatic hybrid plants between O.sativa and展开更多
The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - d...The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - derived lines were chosen from each of the six crosses under both high-and low-fertility for use in this study. In 1995, the total 24 lines were tested in high, medium and low fertility sites with the same experimental design (CRB) to study the selcctoin effects of high and low - fertility. The results suggested that high- and low-fertility had different selection effects. High fertility was more effective for selecting lines, which had higher yield under high-fertility and lower yield under low-fertility; low-fertility was better for selecting lines, which had higher yield under low-fertility and lower yield under low-fertility, and high fertility was somewhat better than low fertility for selecting lines, which had higher yield under both high and low-fertility. It revealed that the lines selected from high-fertility had superior yield potential. The lines selected from high-fertility had shorter plant height, more nodes on main stem, fewer branches, higher seed-stem ratio. The reverse was true for the lines selected from low-fertility . The lodging-resistance of the lines selected from highfertility was greater than that of the lines from low-fertility. The soil fertility level of breeding nursery should be chosen according to the breeding objective.展开更多
文摘Some wild species of Oryza possess agronomi-cally useful traits such as disease/insect resis-tance and salt tolerance.However,the use ofwild Oryza species for rice improvement hasbeen hampered by the sexual incompatibility orsterility of hybrids obtained by conventionalmethods.We have used protoplast fusion as amethod to incorporate useful trait of wild O-ryza species into cultivated rice and~ obtainedsomatic hybrid plants between O.sativa and
文摘The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - derived lines were chosen from each of the six crosses under both high-and low-fertility for use in this study. In 1995, the total 24 lines were tested in high, medium and low fertility sites with the same experimental design (CRB) to study the selcctoin effects of high and low - fertility. The results suggested that high- and low-fertility had different selection effects. High fertility was more effective for selecting lines, which had higher yield under high-fertility and lower yield under low-fertility; low-fertility was better for selecting lines, which had higher yield under low-fertility and lower yield under low-fertility, and high fertility was somewhat better than low fertility for selecting lines, which had higher yield under both high and low-fertility. It revealed that the lines selected from high-fertility had superior yield potential. The lines selected from high-fertility had shorter plant height, more nodes on main stem, fewer branches, higher seed-stem ratio. The reverse was true for the lines selected from low-fertility . The lodging-resistance of the lines selected from highfertility was greater than that of the lines from low-fertility. The soil fertility level of breeding nursery should be chosen according to the breeding objective.
