Heterosis for morphological traits in subtropical maize (Zea mays L.).

Heterosis for morphological traits was exam- ined in maize crosses between inbred lines of contrasting maturities and plant heights in a field study over two years at CCRI, Pirsabak, Nowshera, Pakistan. The parame- ters included days to silking, leaf area, plant height and days to maturity. Except for one cross, mid-parent hetero- sis was significant for all traits in all crosses. Significant better parent heterosis was only found in one of the 4 crosses. Magnitudes of heterosis, both mid-parent and better parent, were positive and higher for leaf area and plant height traits compared to those for days to flower- ing and maturity. Mid-parent heterosis ranged from 24.57%-71.28%, 29.30%-37.85%, -6.03% to -9.74% and 0.82% to -9.53% for leaf area, plant height, days to silking and days to maturity, respectively. Based on the consider- ation of the level of heterosis, the study suggested Pop 9804xFRW4 as the best hybrid combination for early ma- turity and high fodder yield.