高光谱图像中的混合像元问题广泛存在,混合像元的分解效率一直是遥感应用研究的难点和热点.目前成熟的端元提取算法有纯像元指数(pure pixel index,PPI)、内部最大体积法(N-FINDR)、顶点成分分析(vertex component analysis,VCA)、顺序最大角凸锥(sequential maximum angle convex cone,SMACC)、交替最大体积法(alternating volume maximization,AVMAX)、最小体积封闭单形体(minimum volume enclosing simplex,MVES)等,这些算法从图像所有像元中提取纯光谱,具有提取速度慢、精度不高的缺点.为此,该文引入了一种融合简单线性迭代聚类(simple linear iterative clustering,SLIC)超像元分割的高光谱混合像元分解算法.超像元分割技术能够将具有相似特征的相邻像元组成图像块,并保留进一步进行图像处理的有效信息,从而大幅减少参与端元提取的像元数量,为解决上述问题提供了有效的途径.通过试验对比了降维方式(主成分分析和最大噪声分数)、RGB对应关系(6种)、色彩空间RGB (red,green, blue)和LAB (lightness-A-B)、数据格式(JPG, BIN)和算法参数K对高光谱图像超像元分割结果的影响,并进一步分析了SLIC超像元分割结果对2种典型端元提取算法(AVMAX、MVES)产生的不同效果.试验结果表明,随着K值的增大,混合像元分解的时间逐渐增加,均方根误差(root mean square error, RMSE)持平或减少,而JPG(有损压缩)数据格式的时间始终比BIN(无损压缩)数据格式的要短.SLIC+MVES的RMSE略高于MVES的RMSE,低于AVMAX的RMSE,但时间远小于MVES.当K足够大的时候,SLIC+MVES的效果就近似MVES的效果了.在大部分情况下,最大噪声分数的降维效果优于主成分分析.以最大噪声分数作为降维方法、以JPG作为数据格式、以LAB作为色彩空间对混合像元分解结果较为有利.另外,SLIC的参数K的取值在5～10之间较为合适.该研究中的SLIC超像元分割算法简单易行,并且提高了混合像元分解的效率,具备很好的实用价值.

为探讨外引杂交种对改良自育优良玉米自交系HL5311的潜在利用价值,测试分析了HL5311自交系与外引杂交种间11个杂交组合F2群体13个植株性状的表现和分离情况,并与亲本自交系HL5311以及3个大面积推广杂交种的母本自交系郑58、浚9058和PH6WC进行了比较.结果表明:各F2群体13个性状的平均值存在较大差异,且均存在较大分离,变异系数为6.14％～50.06％;除P368群体的株高外,各群体均可用于改良自选自交系HL5311的植株性状;除大部分群体的株高、穗位高和雄穗分枝数以及P483群体的雄穗长外,各群体均分离出优于最优自交系性状的植株.综合各植株性状来看,P399、P483、P573、P571、P400群体的总体表现更为突出,可以作为改良HL5311自交系植株性状的重点基础群体.

In this study,seven excellent maize hybrids and their 13 parent lines were studied for 13 plant traits,including plant height,ear height,top height,top height/plant height,tassel length,tassel branch number,leaves above ear,leaf angle,leaf orientation value,leaf area,aerial root layers,first layer aerial roots and stem diameter.The mid-parent heterosis(MH),over-high parent heterosis(HH) of all hybrids,and the correlations of hybrid with its two parent lines were analyzed for all traits.The results showed that great differences existed among hybrids and parent lines for all traits.MH and HH were greatly different among different hybrids for the same trait and among different traits for the same hybrid.The heteroses of plant height,ear height,top height,tassel length,tassel branch number,the leaves above ear,leaf angle,leaf area and stem diameter were high,but the heteroses of top height/plant height,leaf orientation value,aerial roots layers,first layer aerial roots were low.Significant positive correlations were found between hybrid and its male parent line for top height,top height/plant height,leaves above ear,between hybrid and its female parent line for tassel length and leaf area,and between hybrid and mid-parent value for top height,tassel branches,leaf angle,and leaf area.This result could provide useful information for cross-making in the improvement of plant traits in maize breeding.

In this study,S4 lines were generally selected from 14 F1 basic populations(BP) belonging to the Reid heterotic group,and were crossed with 10 elite inbreds from 3 high heterotic groups.A total of 428 crosses were selected from the 1 902 testcrosses,and their grain starch,protein,oil and lysine content were analyzed and compared with the basic populations and test lines.The result showed that the great differences of crosses were detected in the four traits,the content ranging in 61.90%-77.22%,7.24%-16.92%,3.23%-6.36% and 0.31%-0.50%,respec tively.The basic population,progeny selection and testline all played an important role in the evaluation of derived lines and the screening of testcrosses.The average starch content in crosses of derived lines from population BP13 and their testcrosses with inbred 8C204 was the highest.The high protein content was observed in testcrosses between the derived lines from BP6 and Xun 926,and between the derived lines from BP11 and Chang 7-2.For grain oil content,the highest average value was from the testcrosses of derived lines from BP6 and derived lines from BP3 with L2m.The highest average lysine content came from the testcrosses of derived lines from BP6 and their testcrosses with inbred Xun 926.This result was useful in further making the broad testcross and improving grain quality traits of derived lines.

Using two popcorn inbred lines and six normal corn inbred lines belonging to Reid heterotic group,twelve F1 crosses and their F2 populations were developed.The F1 performance,heterosis,F2 performance and segregation characteristics,and their correlations with parent lines were analyzed for eight ear-kernel characters,including ear length,ear diameter,ear row number,kernel number per row,100 grain weight,ear weight,ear grain weight and kernel rate.The results showed that great differences existed among crosses in F1 performance,mid-parent heterosis(MH) and 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.All traits showed normal distributions in F2 populations,with transgress segregations beyond two parents.For traits with low heterosis,such as ear row number,kernel rate and ear diameter,F1 performance and kernel rate could be predicted according to parent values,while it was unsuitable for traits with high heterosis,such as ear weight,ear grain weight and 100 grain weight.Besides ear row number and kernel rate,significant positive correlations were observed between F1 with F2M,MH and HH,and among F2M,MH and HH.However,they were all negatively correlated with HDR.Three crosses,R2×N04,R4×N10 and R5×N10,were chosen as much better crosses both in genetic mapping and in improvement for ear-kernel characters in popcorn breeding.