Effects of subsoiling depth,period interval and combined tillage practice on soil properties and yield in the Huang-Huai-Hai Plain,China

Compact!on layers are widely distributed in the Huang-Huai-Hai Plain,China,which restrict root growth and reduce yields.The adoption of subsoiling has been recommended to disrupt compacted soil layers and create a reasonable soil structure for crop development.In this paper,the effects of subsoiling depth(30,35 and 40 cm),period interval(2 or 3 years)and combined pre-sowing tillage practice(rotary cultivation or ploughing)on soil condition improvement was studied on a tidal soil in the Huang-Huai-Hai Plain.Seve n tillage patter ns were desig ned by combini ng differe nt subsoili ng depths,period intervals and pre-sowing.The evaluation indicators for soil condition improvement were as follows:thickness of the plough layer and hard pan,soil bulk density,cone index,soil three-phase R values,alkali nitrogen content,crop yield,and economic ben efits.The results showed that subsoiling can sign ificantly improve the soil structure and physical properties.In all subsoiling treatments,the depth of 35 or 40 cm at a 2-year interval was the most significant.The thickness of the plough layer in creased from 13.67 cm before the test to 21.54-23.45 cm in 2018.The thick ness of the hard pan decreased from 17.68 cm before the test to 12.09-12.76 cm in 2018,a decrease of about 40.07%.However,the subsoiling combined presowing tillage practice,that is,rotary cultivation or ploughing,was not significant for soil structure and physical properties.For all subsoiling treatments,the soil bulk density,cone index and soil three-phase R values of the 15-25 cm soil layer were significantly lower compared to single rotary cultivation.Subsoiling was observed to increase the soil alkaline nitrogen and water conte nts.The tillage patter ns that had subsoiling at the depth of 35-40 cm at a 2-year in terval combi ned with rotary cultivation had the highest alkali nitrogen and water contents,which increased by 31.08-34.23%compared with that of the single rotary cultivati on.Subsoiling can sign ifica ntly in crease the yield both of wheat and corn,as well as the economic ben efits.The treatment of subsoili ng at the depth of 35 cm at an interval of 2 years com bined with rotary cultivation had the highest ann ual yield and economic benefits.For this treatme nt,the arinual yield and economic ben efits in creased by 14.55 and 62.87%in 2018,respectively.In con clusi on,the tillage patter ns that involved subsoili ng at a depth of 35 cm at a 2-year interval along with rotary cultivation are suitable for the Huang?Huai-Hai Plain.

A Study on Genotype-by-Environment Interaction Analysis for Agronomic Traits of Maize Genotypes Across Huang-Huai-Hai Region in China

Facing the trend of increasing population,how to increase maize grain yield is a very important issue to ensure food security.In this study,28 nationally approved maize hybrids were evaluated across 24 different climatic conditions for two consecutive years(2018-2019).The purpose of this study was to select high-yield with stable genotypes and identify important agronomic traits for maize breeding program improvement.The results of this study showed that the genotype
environment interaction effects of the 12 evaluated agronomic traits was highly significant(P<0.001).We introduced a novel multi-trait genotype-ideotype distance index(MGIDI)to select genotypes based on multiple agronomic traits.The selection process exhibited by this method is unique and easy to understand,so the MGIDI index will have more and more important applications in future multi-environment trials(METs)research.The genotypes selected by the MGIDI index were G22,G10,G12 and G1 as the high yielding and stable genotypes.The parents of these selected genotypes have the ability to play a greater role as the basic germplasm in the breeding process.A new form of genotype(G)main effects and genotype(G)-by-environment(E)interaction(GGE)technician,genotypeyieldtrait(GYT)biplot,based on multiple traits for genotypes selection was also applied in this study.The GYT biplot ranked genotypes by combining grain yield with other evaluated agronomic traits,and displayed the distribution of their traits,namely strengths and weaknesses.

Evaluation of a new method for quantification of heat tolerance in different wheat cultivars

Heat stress seriously affects wheat production in many regions of the world. At present, heat tolerance research remains one of the least understood fields in wheat genetics and breeding and there is a lack of effective methods to quantify heat stress and heat tolerance in different wheat cultivars. The objective of this study was to use various wheat cultivars to evaluate stress intensity(δ) and a new method for quantification of heat tolerance and compare this technique with three other currently utilized methods. This new parameter for heat tolerance quantification is referred to as the heat tolerance index(HTI) and is an indicator of both yield potential and yield stability. Heat treatments were applied in a controlled setting when anthesis had been reached for 80% of the wheat. The stress intensity evaluation indicated heat shock was the main factor associated with kernel weight reduction while grain yield reduction was mainly associated with chronic high temperature. The methods evaluation showed that a temperature difference of 5°C from natural temperatures was a suitable heat treatment to compare to the untreated controls. HTI was positively correlated with yield under heat stress(r=0.8657, δ=0.15, in 2009–2010; r=0.8418, δ=0.20, in 2010–2011; P<0.01), and negatively correlated with yield reduction rate(r=–0.8344, in 2009–2010; r=–0.7158, in 2010–2011; P<0.01). The results of this study validated the use of HTI and temperature difference control for quantifying wheat heat tolerance that included the yield potential and the stability of different wheat cultivars under heat stress. Additionally, 10 wheat cultivars showed high HTI and should be further tested for their heat confirming characteristics for use in wheat heat tolerance breeding.

Heat stability of winter wheat depends on cultivars, timing and protective methods

Heat stress negatively affects wheat production in many regions of the world.At present,sensitivity to heat stress remains one of the least understood aspects of wheat genetics and breeding,and measures for preventing heat stress are understudied.In this study,we used three cultivars of winter wheat(GY2018,SL02-1 and SY20)to evaluate the effect of heat stress at different days after anthesis(DAA)on yield and quality.Heat stability of the cultivars were analyzed and evaluated for the effects of two kinds of regulators on wheat under heat stress conditions.Heat treatment at 7 DAA led to the most substantial reduction in yield while GY2018 had the best heat stability with respect to yield,and demonstrated the most positive effects on several quality traits including protein content,sedimentation volume and glutenin and gliadin contents.Heat treatment at 14 DAA had the least reduction in yield,while SY20 had the best heat stability with respect to yield and heat treatment had minimal effects on quality.Heat treatment at 21 DAA had only a limited effect on yield,while SL02-1 had the best heat stability with respect to yield,but it showed the most negative effects on quality.Stable time at 14 DAA and protein content at 21 DAA can be used as indicators for detecting the stability of quality under heat stress.Among the three studied cultivars,SY20 was the most sensitive to heat stress with the stable time decreasing from 26.4 to 9.1 min,a higher sedimentation volume at 7 DAA,and a lowerγ-gliadin content which increased 2.4-fold under high-temperature treatment.The addition of various regulators had different effects:potassium dihydrogen phosphate(KDP)was more protective of yield with heat stress at 7 DAA,while Duntianbao(DTB)had better effects on quality with heat stress at 21 DAA.

Efficacy and Phytotoxicity Trial of Different Dosages of 4% Nicosulfuron SC on Weeds in Corn Fields

[Objective]The paper was to study efficacy and phytotoxicity of different dosages of 4% nicosulfuron on weeds in corn fields.[Method]With summer corn variety Zhengdan 958commonly used in field production in Hengshui area of Hebei Province of China as the test material,different dosages（1 050,1 500 and 1 950mL/hm2）of corn postemergence herbicide 4% nicosulfuron SC were sprayed during five-leaf stage of corn,and the treatments with water spraying and manual weeding were set as controls.The effects of different dosages of 4% nicosulfuron SC on weed control efficacy and safety and yield of corn were analyzed in order to determine the optimal dosage.[Result]Spraying 4% nicosulfuron SC with dosage of 1 500mL/hm2 during five-leaf stage of corn not only had better control effect against various weeds,but also did not produce phytotoxicity on corn,and the yield of corn was higher.[Conclusion]The study provided scientific information for using 4% nicosulfuron to eradicate weeds in corn fields.

Extracts from cotton over the whole growing season induce Orobanche cumana(sunflower broomrape) germination with significant cultivar interactions

Five cotton cultivars and their parents were tested for induction of germination of Orobanche cumana Wallr.(sunflower broomrape) seeds in pot and field experiments. Germination rates induced by cotton root extracts were the highest followed by stem extracts then leaf extracts. Cotton seedlings at the six-leaf stage induced higher germination than seedling at the two-and four-leaf stage, in all five cotton cultivars and their parents. In the field, the highest concentration of cotton root extracts gave the highest germination rate of O. cumana, and the lowest concentration of cotton root extracts gave the lowest germination rate. Methanol extracts of cotton rhizosphere soil gave the highest germination of O. cumana. In general,the root, stem and leaf extracts were more active at the sixleaf stage than other seedling stages. In conclusion,extracts of cotton rhizosphere soil and tissues have high activity in the seedling stage. Extracts of cotton across the whole growing season were able to induce O. cumana germination but displayed significant cultivar interactions.

Effectiveness of ten commercial maize cultivars in inducing Egyptian broomrape germination

Egyptian broomrape(EB),Phelipanche aegyptiaca,is a devastating root parasite,causing enormous crop losses around the world.Maize has the potential to influence the growth of other plants through releasing certain allelochemicals and is able to induce germination of at least three broomrape species.To determine whether maize could be used as a trap crop for EB,10 maize cultivars were tested for their ability to induce EB germination.The results showed that maize cultivars can induce EB germination,and that germination rates in a cut-root experiment and a hydroponic experiment were consistent.Maize cvs Changcheng 799 and Zhengdan 958 induced the highest EB germination rates,while cvs Luyu 13 and Zhengyu 203 were the least effective.These four maize cultivars were further studied in a pot experiment.Rhizosphere soil,rhizosphere soil extracts,root extracts and shoot extracts from these cultivars were all able to induce EB germination,with cv.Changcheng 799 inducing the highest germination rates.Root extracts generally induced higher germination rates than shoot extracts.It is suggested that Changcheng799 could be planted as a trap crop for control of EB.