The relationships on grain yield of the new maize hybrid CHUANNONGDANJIAO 9 of maize with density, nitrogen and phosphorus were studied, and a mathematical model involving the three factors which affect yield was established by using the orthogonal rotation design of quadratic regression in the different ecological regions. The effects of inividual factor and its interaction on yield were determined and the optimum agronomic practices in certain conditions were found by analysing the model.

Within 5 years by using the hybrid 3163 from the U.S. Corn Belt as source population through a novel method of synchronous directive shuttle breeding (SDSB) between North and South,a new maize hybrid Zhenghong 2 was developed by early generation test with the inbred line 48-2 as tester,and an inbred line K236 was bred at the same time.

In regional test of middle and late mature of new maize variety in Gansu province from 2003 to 2004,the average yield was 10 919.4 kg/hm2 and 11 464.5 kg/hm2 respectively and the rate of yield increase was 5.2% and 12.0% higher than that of the check zhongdan 2.The main characters of the variety were high and stable yield,good quality,better-resistance and was a stuff maize variety.

A new corn hybrid variety, chuannong single cross number 9, has combined the high yield and excellent disease resistance with good quality. The breeding procedure and main specificities of this variety were descried in the paper. A new effective process of quickly producing corn hybrid variety was developed,which included synthesizing the populations with wide genetic bases for breeding,selecting the inbred lines with high yield,high combining ability and excellent resistance, early progeny test and combination,...

A new corn hybrid variety, chuannong single cross number 9, has combined the high yield and excellent disease resistance with good quality. The breeding procedure and main specificities of this variety were descried in the paper. A new effective process of quickly producing corn hybrid variety was developed,which included synthesizing the populations with wide genetic bases for breeding,selecting the inbred lines with high yield,high combining ability and excellent resistance, early progeny test and combination, increasing selection pressure, and arranging the trials in many environments for better identification and choice.

The relationships on grain yield of the new maize hybrid CHUANNONGDANJIAO 9 of maize with density, nitrogen and phosphorus were studied, and a mathematical model involving the three factors which affect yield was established by using the orthogonal rotation design of quadratic regression in the different ecological regions. The effects of inividual factor and its interaction on yield were determined and the optimum agronomic practices in certain conditions were found by analysing the model. The optimum comprehensive...

The relationships on grain yield of the new maize hybrid CHUANNONGDANJIAO 9 of maize with density, nitrogen and phosphorus were studied, and a mathematical model involving the three factors which affect yield was established by using the orthogonal rotation design of quadratic regression in the different ecological regions. The effects of inividual factor and its interaction on yield were determined and the optimum agronomic practices in certain conditions were found by analysing the model. The optimum comprehensive practices for high yield of the hybrid were, density of about 3500 plants, about 11.0 KG Navailable and about 5.0 KG P_2O_5 available per mu in the centre of the Sichuan Basin and around and in the high yield regions of the east, and density of 2813—3271 plants, 9.6—11.6 KG N available and 3.2—5.2 KG P_2O_5 available per mu in the lower yield regions of the east.

The relationships on grain yield of the new maize hyhrid CHENGDAN 13 of maize with density, nitrogen and phosphorus were studied, and a mathematical model involving the three factors which effect yield was established by using the orthogonal rotation design of quadratic regression in the different ecological regions. The effects of individual factor and its interaction on yield were determined and the optimum agronomic practices in certian conditions were found by analysing the model. The optimum comprehensive...

The relationships on grain yield of the new maize hyhrid CHENGDAN 13 of maize with density, nitrogen and phosphorus were studied, and a mathematical model involving the three factors which effect yield was established by using the orthogonal rotation design of quadratic regression in the different ecological regions. The effects of individual factor and its interaction on yield were determined and the optimum agronomic practices in certian conditions were found by analysing the model. The optimum comprehensive practices for high yield of the hybrid were, density of 3500—4000 plants, about 10.0 KG N available and about 7.0 KG P_2O_5 available per mu in the centre and to the south—east of the Sichuan Basin, and density of 2922—3324 plants, 6.9—8.6 KG N available and 3.4—6.0 KG P_2O_5 available to the north—west.