玉米单交种光合生产能力杂种优势对氮肥的响应

以先玉335和郑单958及其亲本为材料,设不追氮和追氮150 kg/hm~2两个氮处理,研究玉米单交种光合生产能力杂种优势与产量杂种优势的关系及其对氮肥的响应。不追氮条件下,玉米单交种产量杂种优势主要来源于干物质积累量和LAI的杂种优势,叶片光合特性Pn、Gs、Ci和Tr均未表现出杂种优势。追氮150 kg/hm~2条件下,产量杂种优势显著提高,较不追氮高36.6%;除干物质积累量和LAI等群体数量性状仍具有杂种优势外,叶片光合特性Pn、Gs、Tr和SPAD值等个体功能性状也表现出明显的杂种优势。施氮条件下,干物质积累量和LAI的杂种优势没有提高,Pn、Gs、Tr和SPAD值的杂种优势分别较不追氮提高35.8%、55.3%、50.9%和19.6%。施氮条件下玉米单交种产量杂种优势的提高主要来源于叶片光合特性杂种优势的提高,与干物质积累量和LAI的杂种优势无关。

Response of Photosynthetic Capacity Heterosis to Nitrogen Rate in Maize

Field experiment was conducted in which two typical commercial maize hybrids Xianyu335 and Zhengdan958 and their parental inbred lines were grown at N 0 kg/ha(N0) and N 150 kg/ha(N150) respectively, to test nitrogen rate consequences on the relationship of photosynthetic capacity heterosis and yield heterosis. Photosynthetic capacity indexes such as Pn, Gs, Ci and Tr did not express heterosis at N0, yield heterosis was mainly come from heterosis of total dry matter and LAI. At N150, besides the colony quantitative traits such as DM and LAI kept heterosis, the individual leaf photosynthetic functional traits such as Pn, Gs, Tr and SPAD value expressed strong heterosis. N 150 kg/ha application resulted in an increase in yield heterosis by 36.6% compared to that at N0, and increases in heterosis of Pn, Gs, Tr and SPAD value separately by 35.8%, 55.3%,50.9% and19.6%, but the heterosis of total dry matter and LAI did not increase. The improvement of yield heterosis of maize hybrids under nitrogen application conditions primarily attributed to the increase in heterosis of photosynthetic capacity, it had nothing to do with the heterosis of total dry matter and LAI.