Effects of cross-pollination on dry matter accumulation, nutrient partitioning and grain yield of maize hybrids grown under different levels of N fertility
1991
Tsai, C.L. | Huber, D.M. | Warren, H.L. | Tsai, C.Y.
This study was initiated to investigate the relationship between increased kernel sink capacity and fertiliser N use efficiency of maize (Zea mays L). Two hybrids differing in yield potential, Pioneer brand 3732 (P3732) and B73 X Mo17, were grown on field plots with four levels of N fertiliser. The kernel sink of P3732 was modified by cross-pollinating P3732 with pollen from B73 X Mo17. Vegetation and kernal samples collected from the N treatments at mid-silk and at 30, 45 and 60 days post-pollination (DPP) were analysed for accumulation and partitioning of dry matter and N content. Grain yield was also determined. Modification of the P3732 endosperm genotype through cross-pollination significantly increased kernel weight, kernel protein content and grain yield at each level of N treatment, indicating an improvement infertiliser N use efficiency due to an increased sink demand. All three levels of N application produced similar effects on the accumulation and partitioning of dry matter and N in plant parts for both endosperm genotypes. Since the harvest index observed at 30, 45 and 60 DPP was similar between sib- and cross-pollinated plants, the additional nutrients translocated into developing kernels of P3732 cross-pollinated plants were mainly derived from increases in duration of dry matter production and N uptake by vegetative tissues rather than from improved partitioning efficiency.
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