Study On Effects Of Intercropping With Maize Hybrids Of Single Parent Improvement

In general,the different maize varieties utilized ecological niche complementarity principle to inter-and mixed-cropped,and need differences in morphological and physiological characteristics or resistance.It turned out to be a effective way to increase stress resistance of maize population,grain yield and population genetic diversity.Yet,to the best of our knowledge,this diversity technology has several limitations: it seldom involves related breeding concepts and methods;in addition,there are many difficulties in keeping uniformity,such as the non-uniformity of maturation times,growth periods and end-use qualities,which always bring lots of trouble to cultivation,production and marketing.What's more,the cultivars are limited to reach the certain intercropped standards.These factors illustrated above have restrictions in popularizing and applying this technology.From the breeding programs point of view,the male parent of the maize cultivar Yudan606 was improved,and two hybrids were selected from the cross between the female parent and improved male parents.The criteria for choosing the hybrids of single parent improvement were similar to Yudan606 in plant,ear and grain types.These improved hybrids should have good performances on grain yield and quality,and have difference in plant height.Among them,Yudan606,about 300 cm,had good performance but is prone to develop abnormal ears under high temperature stress;607,nearly 287 cm,exhibited good performance of ear development;613,about 284 cm,had high yield potential but less resistance to stalk rot.Then the treatments of Yudan606 intercropping with hybrids of male parent improvement were carried out.This study was conducted under field conditions at Xiping(the south of Henan Province),Zhengzhou(the central Henan Province)and Sanya(southern Hainan Province)in 2015,using one maize variety(Yudan606)and two male parent improved hybrids(607 and 613).The objective of this study was to investigate the effects of compound colony on yield,agronomic characters,stress resistance and grain quality in intercropping with maize hybrids of single parent improvement.The results were as follows: 1 The yields and LER on intercropping with maize hybrids of single parent improvement.There is a effect of “1+1>2” on the intercropping with YD606 and its hybrids of single parent improvement.The yield of 606 || 607 was 0.8% ~ 12.7% higher than 1/2(606 S+607 S),and the average yield of all sites was increased by 6.2%.The yield of 606 || 613 was 0.6% ~ 7.1% higher than predicted yield,and the average yield of all three sites was increased by 2.6%.The yield of 606 || 607 was generally higher than monoculture of the high yield hybrid.Also,land equivalent ratio(LER)was enhanced in the intercropped compound colonies.2 Agronomic characteristics on intercropping with maize hybrids of single parent improvement.The reasonable difference of plants height plays an important role in genetic diversity populations.It can optimize the group structure,improve the aeration and transmittance condition of the compound colony and finally enhanced the yield.Compared to the monoculture hybrids,the plant height,evenness degree of height and ear height showed the downtrend;and the basal third eustipes diameter had a increased trend.These change trends have a positive influence on increasing resistance to lodging.3 The disease resistance on intercropping with maize hybrids of single parent improvement.This study showed that reasonable intercropping of maize cultivars with its hybrids of single parent improvement could enhance the resistance to diseases,especially under the severe conditions.YD606 and its hybrids of single parent improvement had similar disease index of southern corn rust and ear rot,but the ability to resist air-spread diseases was enhanced by intercropping compound colony.It may be due to the improvement of microclimate in the field.For physiological disease,the population density of high incidence hybrid was diluted.Consequently,the incidence rate of intercropped population was decreased,and the yield was increased.4 The grain quality on intercropping with maize hybrids of single parent improvement.In the period of selecting breeding materials,the uniformity of ear and grain type were considered.The reasonable intercropping with maize cultivars with its hybrids of single parent improvement had no effect on the uniformity of grain quality.So it could meet the needs of modern corn industry and feed processing.