不同种植密度下玉米Lancaster群改良系的杂种优势及配合力

为耐密植玉米新品种的选育提供参考,以玉米Lancaster群5个改良自交系为父本,Reid群和Dom群5个骨干自交系为母本,按NCⅡ设计组配25个玉米杂交组合,研究5.5万株/hm~2、7万株/hm~2和9万株/hm~2种植密度对各杂交组合及亲本单株产量杂种优势及配合力的影响。结果表明:在3种种植密度下,25个玉米杂交组合单株产量的杂种优势分别为137.12%、134.90%和127.86%,且杂种优势随种植密度的增加而降低;但PH4CV改良自交系父本所配杂交组合在高密度种植条件下的杂种优势较高。在5.5万株/hm~2种植密度下,一般配合力以自交系PH5AD最高,为7.02;在7万株/hm~2和9万株/hm~2种植密度下,以自交系PH4CV最高,分别为20.73和18.24。以PH5AD为父本所配杂交组合适宜稀植,以PH4CV为父本所配杂交组合在高密植条件下易获高产;以PH4CV为父本所配杂交组合较耐密植,以J1577为父本所配杂交组合宜稀植。

Heterosis and Combining Ability from Improved Lines of Maize Lancaster Group under Different Densities

To provide references for breeding new maize cultivars tolerant to dense planting,taking five improved inbred lines of Lancaster group as male parents,five backbone inbred lines of Reid and Dom groups as female parents,the NC Ⅱ design was employed to explore the effects of various planting densities (55 000 plants/hm2,70 000 plants/hm2,90 000 plants/hm2) on per plant yield heterosis and combining ability of hybrid combinations and parents.Results:Per plant yield heterosis of maize under planting densities of 55 000 plants/hm2,70 000 plants/hm2 and 90 000 plants/hm2 was respectively 137.12％,134.90％ and 127.86％,which gradually diminished with density increasing;While the improved line PH4CV had high heterosis in the high density.Under the 55 000 plants/hm2 density,the improved line PH5AD had the highest GCA effect(7.02).Under the 70 000 plants/hm2 and 90 000 plants/hm2 density,the improved line PH4CV had the highest GCA effects of 20.73 and 18.24.It illustrated that the combinations with PH5AD as male parent were suitable for thin planting,that with PH4CV as male parent could obtain higher yield under high density planting;The combinations which were produced by PH4CV as male parent were more preferable under high density,the combinations which were produced by J1577 as male parent weren't suitable under high density.