Flowering Syndrome-Hybrid Performance Relationship in Maize 2- Grain Yield and Yield Components

摘要

A field experiment was conducted for 4 seasons on the farm of the Dept. of Field Crop Sci., Coll. of Agric., Univ. of Baghdad in spring and fall plantings in 2014 and 2015. That was to determine the relationship of hybrid performance in maize (Zea mays L.) crosses with early and late selects of inbreds. Four inbreds; Zm19, Zm32, Zm51, and Zm61 were grown and the very early and very late silking plants were selected and selfed for propagation in the first two seasons. The third season involved growing the selects and top-crossing with early and late inbreds (Zm60 and Zm21). The sixteen crosses were planted in season 4 in RCBD of 3 replicates in population density of 83'000 plants. ha~(-1). The cross (Zm19×Zm60) resulted from early select of Zm19 gave significantly higher grain yield (10.52 t. ha~(-1)) compared to its late counterpart (8.19 t. ha~(-1)). The same cross gave higher grain yield than late Zm19 crossed to late inbred (Zm21) (6.64 t. ha~(-1)). Early selects on inbreds crossed to testers showed significant differences in kernel growth rate (KGR), kernel filling duration (KFD) and kernel weight. Values of KGR ranged between 3.2 - 3.5 g. plant~(-1). d~(-1), KFD between 35 - 38 d, and kernel weight between 228 - 294 mg. kernel~(-1). It was concluded that selection on maize inbred populations creates new variations in traits lead to higher grain yield hybrids. Other traits such as ear length, kernel. ear~(-1), and kernel weight could be good candidates for selection on inbreds that could help developing new high grain yield hybrids.