Path analysis of summer maize agronomic traits and yield in the Huang-Huai-Hai Plain

The increasing water shortage in the agricultural sector in the Huang-Huai-Hai Plain (3HP) necessitates the selection and growing of more summer maize varieties with high yield and water use efficiency (WUE). A total of 11 hybrid maize varieties (commonly grown in the 3HP) were selected and planted in a random design and water-saving condition. The crops were irrigated only once at seeding stage. The agronomic traits, WUE and yield of the crops were analyzed via path coefficient and principal component analysis. The results showed that the yields of "Huafeng 8", "Liyu 18", "Jundan 20" and "Jiyu 3" exceeded 10 000 kg·hm^-2 with WUE greater than 3.0 kg·m^-3. This set of crops belonged to high WUE and super-high-yield type hybrid maize variety. Yields of "Yuanshen 213" and "Zhongke 11" were greater than 9 000 kg·hm^-2 with WUE of at least 2.7 kg·m^-3, this set of crops belonged to high WUE and high-yield type hybrid maize variety. The yields of "Jundan 18", "Denghai 662", "Jinong 1" and "Denghaichaoji" were higher than 8 000 kg·hm^-2 with WUE of 2.3~2.7 kg·m^-3, and which belonged to the stable-yield type hybrid maize variety. Principal component analysis showed that "Jiyu 3", "Liyu 18", "Huafeng 8" and "Jundan 20" were excellent varieties in terms of drought-resistance, water-saving and high-yield traits, and should therefore be widely cultivated in the study area of 3HP. Also based on path analysis, the comprehensive effects of 7 main agronomic traits on yield ranked as follows: core weight > 100-grain weight > row kernel number > bald point length > kernel length > ear length > ear row number. Whereas core weight, row kernel number and 100-grain weight had the most positive direct effect on yield, bald era length had the most negative effect on yield. The results of this study laid the basis for the selection and promotion of maize varieties with good traits for drought-resistance, water-saving and high-yield in the 3HP region.