玉米F_1、F_2代植株性状的遗传背景及适宜群体筛选

利用2个优良爆裂玉米自交系与6个Reid类普通玉米自交系组配12个组合,研究了株高、穗位高、顶高、顶高/株高4个植株性状的F1表现、杂种优势、F2群体表现和分离特征及其与亲本的相关性。结果表明:不同组合F1表现、中亲优势(MH)、超高亲优势(HH)、F2群体的平均值(F2M)、变幅、变异系数、优势衰退(HDR)等均存在不同程度差异,各植株性状杂交早代的遗传背景效应突出;F2群体各性状多呈连续正态分布,存在超双亲分离,为多基因控制的复杂数量性状;顶高/株高杂种优势较小,可根据两类亲本或其均值初步预测其组合表现,并实施早代选择,而株高、穗位高和顶高的杂种优势较大,不宜进行预测;亲本、F1、F2M、MH、HH、HDR间的相关趋势因性状不同而异;R1×N04、R3×N04组合为改良爆裂玉米自交系植株性状的最佳群体,R2×N10、R3×N04、R5×N10和R6×N04组合适宜构建遗传作图群体。

Genetic Background Effects of F1 and F2 Generations for Plant Characters and Suitable Population Selection in Maize

In this study,two excellent popcorn inbred lines and six normal corn inbred lines belonging to Reid heterotic group were used to make 12 F1 crosses and their F2 populations.Eleven plant traits were analyzed for F1 performance,heterosis,F2 performance and segregation characteristics,and their correlations with parent lines,including plant height(PH),ear height(EH),top height(TH),top height/plant height(TP/PH).The results showed that great differences existed among crosses in F1 performance,mid-parent heterosis(MH),over-high parent heterosis(HH),and mean value(F2M),range,variation coefficient and hetrosis decreasing rate(HDR) in F2 populations,reflecting obvious genetic background effects.Most traits showed normal distributions in F2 populations,with transgressive segregations beyond two parents.For traits with low heterosis,such as TP/PH,selection could be done in early generations,and their F1 performance and F2M could be predicted according to parent values,while it was not suitable for traits with high heterosis,such as PH,EH and TH.Correlation coefficients among parent value,F1,F2M,MH,HH and HDR were different.R1×N04 and R3×N04 were chosen as much better crosses in improvement for plant characters in popcorn breeding,while R2×N10,R3×N04,R5×N10 and R6×N04 were suitable in simultaneously genetic mapping for most plant characters.