Genetic Differences Of N,P,K Absorption And Utilization Efficiency In Sweet Maize

In this study, 22 new varieties of sweet maize (Zea mays L. Sacchavata sturt) in China were conducted to investigate their genotype differences in the absorption and utilization of N, P and K. The field experiment was carried out in 2004-2005. The dynamic changing of N, P and K in absorption, accumulation and utilization in sweet maize were analyzed, the relationship of absorption and utilization in N, P and K with yield were clarified and the varieties with high yield and high NUE(Nitrogen utilization efficiency), high PUE (phosphorus utilization efficiency ) or high KUE(potassium utilization efficiency) were screened. The main results were as follows:1. Genotype differences on absorption and utilization of N, P and K in sweet maize Under the same fertility condition, the yield, nutrient absorption quantity and nutrient utilization efficiency were significantly difference among varieties. The ranges of fresh ear yield and fresh kernel yield were 7323.65kg/hm2~11800.95kg/hm2 and 5129.13kg/hm2~8530.73kg/hm2, respectively. The ranges of N, P, K absorption were 126.58kg/hm2~243.76kg/hm2, 15.25kg/hm2~38.99kg/hm2, 97.49kg/hm2~206.19kg/hm2, respectively. The ranges of N, P, K utilization efficiency for fresh ear among varieties were 43.49kg/kg~61.98kg/kg, 286.57kg/kg~480.36kg/kg, 49.60kg/kg~85.04kg/kg, respectively. The ranges of N, P, K utilize efficiency for fresh kernel were 28.39kg/kg~46.01kg/kg, 198.13kg/kg~338.51kg/kg, 35.02kg/kg~52.83kg/kg, respectively. The results indicated that increase N, P, K absorption quantity were more important than utilize efficiency to increase fresh ear and kernel yield. Through cluster analysis, 3 varieties had high yield and high NUE, 3 varieties had high yield and high PUE, 4 varieties had high yield and high KUE, regardless the product were fresh ear or fresh kernel. Only SM9701 and JSW had high yield, high NUE, high PUE and high KUE in 22 sweet maize varieties. Mean of NUE .PUE. KUE for SM9701 and JSW were 52.29kg/kg, 39.22kg/kg., 349.43kg/kg , 262.53kg/kg, 59.59kg/kg and 44.72kg/kg.respectively.2. Genotype differences on accumulation of N, P and K in sweet maizeThere are significant difference in N, P, K content and accumulation in jointing stage, flowering stage and fresh days among varieties. These difference contributed to the different yield and nutrient utilization efficiency. The varieties with high yield had high N accumulation from jointing stage to fresh days, The varieties with high NUE for fresh ear had less accumulation quantity from jointing stage to fresh days, The varieties with high NUE for fresh kernel have less N accumulation rate from jointing stage to fresh days. The varieties with high yield had high P accumulate rate from flowering stage to fresh days, and the varieties with high PUE have less P accumulate rate from flowering stage to fresh days. The varieties with high yield have low K accumulation rate and high K accumulation quantity before jointing stage. The varieties with high ear KUE had high accumulation quantity and low accumulation rate before jointing stage. The varieties with high kernel KUE had low accumulation quantity from jointing stage to fresh days. For SM9701 and JSW, two varieties with high yield and high N, P, K absorption and utilization efficiency, the mean N accumulation quantity before jointing stage, from jointing stage to flowering stage, from flowering stage to fresh days were 0.246 g/plant, 2.229g/plant, 1.420g/plant. 0.038g/plant, 0.349g/plant, 0.230g/plant for P accumulation quantity, 0.306g/plant, 2.95g/plant, 0.173g/plant for K accumulation quantity.3. Genotype differences on distribution characters of N, P and K in sweet maizeThere are significant difference on distribution characters of N, P, K in fresh days among varieties, and the distribution of nutrient had greatly influence on yield and nutrient utilization efficiency. The varieties with high fresh ear yield had high N distribution quantity in lamina and kernel. The varieties with high fresh kernel yield had high N distribution quantity in lamina and tassel. The N distribution quantity were low in lamina, sheath, axis for varieties with high fresh ear NUE. The N distribution quantity were low in lamina and axis for varieties with high fresh kernel NUE. The P distribution quantity were high in kernel for varieties with high fresh ear and kernel yield. The varieties with high PUE for fresh ear were mainly due to low P distribution quantity in sheath and stem. The varieties with high PUE for fresh kernel were mainly due to low P distribution quantity in sheath and axis. The K distribution quantity were high in lamina and sheath for varieties with high fresh ear yield. The K distribution quantity were high in sheath and stem for varieties with high fresh kernel yield. The varieties with high KUE for fresh ear and kernel had low K distribution quantity in sheath and axis.The varieties with high fresh ear and kernel yield had low N distribution rate in axis. The N distribution rate in kernel were low for varieties with high fresh ear NUE. The P distribution rate in were low in tassel for varieties with high fresh ear yield. The P distribution rate were low in axis and high in kernel for varieties with high fresh kernel yield. The varieties with high PUE for fresh ear had high P distribution rate in kernel and bract. The varieties with high PUE for fresh kernel had high P distribution rate in kernel and low in axis. Low K distribution rate were found in kernel for varieties with high fresh ear yield. The K distribution rate were low in bract and axis and high in tassel for varieties with high fresh kernel yield. The varieties with high KUE for fresh ear and fresh kernel were mainly due to high K distribution rate in stem. The nutrient distribution characters in different organs of SUIMEI9701, JSW afforded basis to estimate the genotype with high yield and high NUE, PUE, KUE.