| The inbred lines of maize consisting of 4 external maize (♀)and 6 early mature maize(♂)were tested in the NCⅡincomplete parallel cross design,24hybrid combination were breeded,Zhedan 7 and its inbred lines 3081,Mo17 were control hybrid, several studies were as follows:1.24 hybrid combinations and its inbred lines were compared and evaluated on drought resistance from growth and development traits, drought-resistance esistance physiological index of seedling emergence and andmorphological traits, yield traits, growth period traits etc of adult period by the direct identification and indirect identification of drought resistance, screening hybrid combinations and its inbred lines of high synthetic drought resistance,synthetical analysis two evaluation methods, some conclusions were determined briefly:(1)In the seedling emergence stage, embrace-2 were considered to be the highly drought resistance inbred lines;Hai104were considered to be the strong drought resistance inbred lines; Hai104×Embrace-2, Hai104×Embrace-1,W59×Embrace-1,Qing-7×Embrace -1, 917-17×Embrace-5 and 917-17×Embrace-4 were considered to be the highly drought resistance hybrid and Qing-7×Embrace-6 were considered to be the strong drought resistance hybrid.(2)In the adult period stage,Embrace-3,MO17were considered to be the highly drought resistance inbred lines;Embrace-2 and Hai104were considered to be the strong drought resistance inbred lines;Hai104×Embrace-1,W59×Embrace-1 and Hai104×Embrace-5 were considered to be the highly drought resistance hybrid; Hai104×Embrace-2,W59×Embrace-2,Qing-7×Embrace-1,Qing-7×Embrace-6 were considered to be the strong drought resistance hybrid.2 Heterosis analysis on drought-resistance traits, several conclusions were as follows:(1)The Mid-parent heterosis order of each traits of hybrid combinations on seedling emergence was seedling fresh weight>survival rate>relative water content>relative germination index>seedling drought-resistance character>plant height>base relative growth increment>relative germination rate.From the proportion of over-parent heterosis, the heterosis of hybrid combinations was stronger in survival rate, relative germination rate, seedling drought-resistance character, plant height, relative water content, seedling fresh weight, relative germination index and base relative growth increment,and over-high parent heterosis was 76%,72%,68%,64%,64%,60%,56%,54%.(2)The Mid-parent heterosis order of each traits of hybrid combinations on adult period was Single Plant Yield>ASI>100-grain weight>ear length>ear row number>kernel number per row>plant height>leaf area of the ear>ear height>growth period. From the proportion of over-parent heterosis, the heterosis of hybrid combinations was stronger in plant height,100-grain weight, Single Plant Yield,leaf area of the ear,ear height,ASI and ear row number, and over-high parent heterosis was 64%,60%,56%,52%,48%,48%,44%. But it was weaker in growth period and its growth period was relatively lower than that of early mature parent.3 The genetic analysis of maize drought resistance showed that the GCA of different parents and the SCA of different combinations were quite different, the fact that there were higher estimated wide-sense heritability for drought resistance revealed this trait could express in the off springs.The lower narrow-sense heritability indicated that drought resistance selecting of inbred lines should be in higher generation.
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