玉米品种更替过程中品种群体整齐度的变化

选用1950~2010年具有代表性的11个品种,设置4个种植密度,测定株高、穗位高、果穗长、穗粗、穗行数、行粒数指标的整齐度。结果表明,随着品种的更替,株高、穗位高、穗长、穗粗、穗行数、行粒数的整齐度明显提高,株高整齐度的提升最为突出。随着种植密度的提高,玉米的群体整齐度下降,现代品种对增密响应更加明显;同等密度条件下,现代品种的群体整齐度均高于早期品种。相关分析表明,玉米产量与株高、穗位高、穗长、穗粗、穗行数、行粒数性状的整齐度具有明显正相关关系。玉米产量提升过程与品种的群体整齐度同步,株高、穗位高整齐度是最为直观的评价指标,通过品种改良和种植技术的改进提高群体的整齐度是进一步提升产量的技术途径之一。

Changes in Population Uniformity Among Maize Varieties from Different Eras

Eleven maize cultivars widely popularized and utilized in China released from the 1950s to 2010s were tested at a range of plant population densities. Plant height, ear height, ear length, ear diameter, row number per ear, kernel numbers per row was recorded and the regular degree(RD) of these was calculated. The results showed that the RD of plant height, ear height, ear length, ear diameter, row number per ear, kernel numbers per row significantly increased with cultivars improved, especially plant height RD. When plant density increased, RDs of maize cultivars were almost reduced, especially modern cultivars. The RDs of traits in newer cultivar were more than in older cultivars at the same cultivation. The correlation analysis indicated that yield was positively correlated with these traits RD. In all, The RD of plant and ear in maize cultivars were increase together with maize yield improved. Plant height RD and ear height RD are the most visualized evaluation indexes. The improvement of population uniformity is one of the technical ways to further improve yield by improving cultivars and cultivation techniques.