Evaluation On Maize Semi-exotic Popula-tions Earlier Generation Lines With Diffe-rent Temperate And Tropical Germplasm Percentage

Using tropical and subtropical maize germplasm to improve temperate germplasm is a mainmethod to broaden and innovate the narrow germplasm.Tropical germplasm ’s improvement andutilization has been explored for many years, many maize hybrids has been cultivated aswell.Much mixed ratio has also been put forward, but the view were different.The semi-exoticpopulations containing the temperate germplasm percentage of twenty-five,fifty and seventy-fivehave been built with CIMMYT populations-Pool18,Pob28, Pob21and domestic temperate inbredlines which have the closest heterosis relationship with the three exotic populations thatexperienced adaptive improvement from the south to the north by Chinese Academy ofAgricultural Sciences (CAAS).The heterosis and combining ability of some semi-exoticpopulations earlier generation lines were tested to study their improvement effects and heterosisrelationship. The improvement value of the early generation lines were confirmed based on thecombining ability,while the heterosis utilization direction of the combination were confirmedbased on the yield and heterosis in order to provide theoretical basis and material support for theusing of CIMMYT and the innovation of germplasm.The main results were summarized as followed:(1)The improvement value and heterosis utilization direction of the earlier generations linesof semi-exotic population containing twenty-five temperate germplasm percentageAmong lines selected from semi-exotic population(Mo17×Pool18)×Pool18,13300,13301,13305,13306,13311,13312had great value to be improved and utilized. The heterosis utilizationdirection of13300,13301,13306,13311was Reid group and that of13312was Ldhg group. Thecombination composed of13312with Luyuan92had great potential of high yield.Among lines selected from semi-exotic population(Ye478×Pob28)×Pob28,13256,13257hadgreat value to be improved and utilized. The heterosis utilization direction of13256,13257wasLancaster group.The combination composed of13257with Longkang11,He344and Dong8112,13255with Dan340had great potential of high yield.Among lines selected from semi-exotic population(Huangzao4×Pob21)×Pob21,13348,13349,13353had great value to be improved and utilized. The heterosis utilization of them was Reid group. The combination composed of13348with B84,13349with B84,13353with9041hadgreat potential of high yield.(2) The improvement value and heterosis utilization direction of the earlier generations linesof semi-exotic population containing fifty temperate germplasm percentageAmong lines selected from semi-exotic population Mo17×Pool18,13320,13321,13322,13327,13332,13334,13338had great value to be improved and utilized. The heterosis utilizationdirection of13321was Reid group and that of13320,13322,13327,13332,13334,13338was Ldhggroup.The combination composed of Luyuan92with13320and13338,Dan340with13322,13332,13334,Ye478with13322had great potential of high yield.Among lines selected from semi-exotic populationYe478×Pob28,13261,13265,13272,13277had great value to be improved and utilized. The heterosis utilization direction of13261,13277wasLancaster group and that of13265,13272was Ldhg group. The combination composed of Dan340with13262,13265,13267,13268,13270,13272,13276and13277had great potential of high yield.Among lines selected from semi-exotic population Huangzao4×Pob21,13358,13359,13360,13363had great value to be improved and utilized. The heterosis utilization direction of13358wasLancaster group and that of13359,13360,13363was Reid group. The combination composed of13363with B84had great potential of high yield.(3)The improvement value and heterosis utilization direction of the earlier generations linesof semi-exotic population containing seventy-five temperate germplasm percentageAmong lines selected from semi-exotic population（Mo17×Pool18）×Mo17,13340,13341hadgreat value to be improved and utilized. The heterosis utilization direction of13340was Reidgroup and that of13341was Ldhg group.The combination composed of13340with Ye478andDan340,13341with Dan340had great potential of high yield.Among lines selected from semi-exotic population (Ye478×Pob28)×Ye478,13379,13280,13282,13283,13285,13286,13294,13295had great value to be improved and utilized. The heterosisutilization direction of13286was Lancaster group;that of13282,13294,13295was Ldhg group;that of13280was Lancaster group or Ldhg group.The combination composed of Dan340with13282,13283,13286,13292,13294,13295,13296,He344with13286,13291, Dong65003with13286,13295, Luyuan92with13280,13291had great potential of high yield.Among lines selected from semi-exotic population(Huangzao4×Pob21)×Huangzao4,13368,13371,13372,13378,13380,13381,13382had great value to be improved and utilized. Theheterosis utilization direction of13371,13378was Lancaster group;The heterosis utilizationdirection of13368,13372,13380,13381,13382was Reid group. The combination composed of B84with13372,13382,13384,Zheng58with13378,13381,9041with13374,Jinhuang96B with13374had great potential of high yield.(4)The improvement value of the earlier generations lines of semi-exotic populations withdifferent temperate and tropical germplasm percentage During semi-exotic populations build with Pool18,Pob21,Pob28containing differentproportions of temperate germplasm,(Ye478×Pob28)×Ye478,(Huangzao4×Pob21)×Huangzao4,Mo17×Pool18had the great value to be improved and utilized. The heterosis utilization directionof them were Reid,Lancaster and Lancaster group separately.