Abstract: The four series near isogonics lines from four common wheat varieties backcrossing thirteen dominant dwarfing sources were studied. The two-factor comparative experiment of these near isogonics lines was conducted under non- competitive conditions in order to investigate the effects of the genetic backgrounds of the dwarfing genes and the recurrent paternal parents on the plant height and grain weight. Under the unified genetic backgrounds, the plant height of all the 13 dwarfing sources ranged from 38. 3- 73. 2 cm, being in a signif icant correlat ion with their grain weight per plant (r= 0. 868 9). The grain weight of a dwarfing source variety approached or exceeded its recurrent parent when its plant height was increased to 64. 2 cm or more. Its therefore, was possible to use such innovative dwarfing sources directly in hybridization breeding of wheat. But the plant height of near isogenies lines with SW07, SW05 and RHT21 was significantly higher than that with others. Compared with the recurrent parent plant which was 92. 5 cm, the reduction of plant height in near isogonics lines with SW07, RHT21 and SW05 dwarfing source was 73??2, 72??4 and 69??5 cm respectively The plant height of near isogenies lines with SW02 and SW04 were 59.7 and 56.9 cm respectively and had significantly difference at 5% level. The grain weight of plant of near isogenies lines with SW05 and SW07 was 17.6 and 15.9g respectively and had significantly higher than that of male parents, which was 14.0 g, and than that with others which was bellow 14.0 g. The RHT10 dwarf ing source had affected the grain weight of plant and plant height of recurrent male parents most. The reduction of plant height and grain weight in near isogonics lines with Rht10 was 58.7% and 57.1% respectively compared with recurrent parent. It is recommended that the dominant dwarfing sources developed and selectedi. e. SW07, SW05, Rht21, Olsen dwarf, YD be utilized in gene-designed?? dwarfing breeding of wheat.

Key words: Dominant dwarf ing source, Near isogenies lines, Plant height, Grain weight of plant

CLC Number: 

• S512.1