黄淮海平原北部高产夏玉米群体生理指标研究

试验以浚单20、丰玉4、京单28品种为试验材料,研究黄淮海北部平原区有限光热资源条件下夏玉米高产群体生理指标。研究结果表明,通过增加夏玉米种植密度,提高收获穗数,从而提高收获总粒数可以有效地提高产量;但密度增加必导致群体过大,后期叶面积指数下降较快,叶片衰老严重,影响吐丝后光合势增加和干物质积累,因此有效减缓高产群体吐丝后的叶片衰亡是实现夏玉米产量的重要保障。黄淮海北部平原区产量突破11 250kg/hm2的夏玉米群体生理指标为:叶面积指数在吐丝期达到5.80以上,后期下降缓慢,到收获时仍维持在3以上。全生育期总光合势达到370(万m2.d)/hm2以上,吐丝后光合势占总光合势的70%以上,群体的干物质积累总量为20 562kg/hm2以上,吐丝后干物质积累量占总积累量的61%以上。高产夏玉米产量构成因素为收获总穗数不少于76 500穗/hm2,穗粒数不少于500粒/穗,总粒数达到3 900万粒/hm2以上,千粒重350g以上,经济系数在0.53以上。

Physiological Characters of the Summer Maize Population with High Yield in the North Areas of the Yellow River, Huai and Hai Rivers Plain

Three maize hybrids Xundan 20, Fengyu 4 and Jingdan 28 were used to study the physiological characters under high-yield condition in Northern plain of the Yellow river, Huai and Hai rivers. The results indicated that the yield, harvested ears and kernel numbers were improved with the increase of planting density, but which lead to increased population to be large. The leaves declined serious, it affected increasing of leaf area duration (LAD) and dry matter accumulation (DMA). So the leaf in a senescence of high-yield groups after flowering stage which effectively slow down was to achieve an important guarantee for summer maize yield. The physiological characters of summer maize population with yield potential higher than 11 250 kg/ha should meet the following criteria, maximum leaf area index (LAI) over 5.80 in flowering stage and maintained above 3 in harvest with slow decreasing. The total leaf area duration (LAD) should be over 370×10⁴(m²·d)/ha and keep 70 % of total LAD after flowering. The total amount of dry matter accumulation should be arrived at 20 562 kg/ha with 61% of the amount of dry matter accumulated after flowering. The yield components of high-yield summer maize were 76 500 harvested ears/ha, 500 grains per ear, 39 million/ha total kernel numbers with thousand grain weight of 350 g, and harvest index above 0.53.