Evaluation Of Resistance Leave Among Different Wolfberry Varieties To Aphis Gossypii Glover

Wolfberry aphids belongs to Hemiptera:Aphididae,which is an important pest that harms a variety of plants such as Solanaceae,Malvaceae,Rutaceae,Cucurbitaceae and so on,among which Aphis gossypii Glover is the dominant population in Ningxia region.The nymph and adult of A.gossypii feed on the young tissues of wolfberry(young leaves,young shoots and green fruits,etc)with together,resulting in a decline in goji berries fruit,reduced yield or even no harvest.In addition,the large-scale use of chemical pesticides can induce a series of problems such as food safety,medicinal value and aphid resistance.Therefore,the aphid resistance of A.gossypii on 4 main wolfberry varieties was investigated in Ningxia region.The feeding behaviors of A.gossypii on 4 wolfberry varieties were explored using electrical penetration graph technology,and the physical and chemical characteristics of wolfberry varieties were measured and compared,Set up an indoor population life table,at the same time,the aphids were artificially received in the field,and the aphid resistance levels were identified,furthermore,the free choice of wolfberry leaf by indoor aphids was observed.The goals of our study are expected to provide theoretical support for the selection and breeding of aphid-resistant wolfberry varieties and the green prevention and control of A.gossypii in wolfberry planting areas.It main research results are as follows:1.The aphid-resistance of different wolfberry varieties was identified by aphid ratio method.The results showed that the resistance to A.gossypii on Ningqi No.1 is the strongest,followed by Ningqi No.5 and Ningqi No.7,Ningqi No.10 is the weakest.2.The leaf disc test was used to study the free selection of wolfberry varieties by A.gossypii.The results showed that there were significant differences on the free selection of different wolfberry varieties by A.gossypii,among which the free choice of Ningqi No.1 was the lowest but the free choice of Ningqi No.10 was the highest.3.The age-stage two-sex life table was used to obtain the growth and population parameters of A.gossypii after feeding on different wolfberry varieties.The results showed that there were significant differences in the oviposition period,fecundity and longevity of A.gossypii on different wolfberry varieties.The oviposition period,total longevity,adult longevity and fecundity of A.gossypii feeding on ’Ningqi No.1’ were significantly lower than ’Ningqi No.5’,’Ningqi No.7’and ’Ningqi No.10’.In addition,there are significant differences among net reproductive rate(R0),gross reproductive rate(GRR),intrinsic rate of increase(r),mean generation time(T)and finite rate of increase(λ)of A.gossypii feeding on different wolfberry varieties.The R0,GRR,r and λvalues of A.gossypii feeding on ’Ningqi No.1’ were significantly lower than ’Ningqi No.5’,’Ningqi No.7’ and ’Ningqi No.10’.The T value of A.gossypii on ’Ningqi No.1’ was significantly lower than’Ningqi No.10’,higher than ’Ningqi No.7’.The results showed that A.gossypii had the lowest adaptability on Ningqi No.1 and the highest adaptability on Ningqi No.10.4.The feeding behaviors of A.gossypii on 4 wolfberry varieties were recorded using electrical penetration graph technology.The results showed that A.gossypii fed on different wolfberry varieties showed eight kinds of waveforms,including Np,A,B,C,Pd,E,G and F waveforms.During thefeeding of A.gossypii,the duration of E1 waveform on Ningqi No.1 was the longest,followed by that on Ningqi No.5 and Ningqi No.7,and that on Ningqi No.10 was the shortest.The total duration of E2 waveform on Ningqi No.10 was the longest,and that on Ningqi No.1 was the shortest.The total duration of F waveform on Ningqi No.1 was the longest,and that on Ningqi No.10 was the shortest,and the duration on Ningqi No.5 and Ningqi No.7 was between Ningqi No.l and Ningqi No.10,suggesting that Ningqi No.1 have strong mechanical resistance and Ningqi No.10 have weak mechanical resistance.The results showed that the preference level of A.gossypii was the lowest on Ningqi No.1 and the highest on Ningqi No.10.5.The study of physical characteristics and their correlation with the aphid number ratio on different wolfberry varieties.The results showed that there were significantly different in physical characteristics such as surface wax content,vascular bundle depth,and thickness of cuticle of leaf among different resistant wolfberry varieties,Among them,the aphid-susceptible variety"Ningqi No.10’ of Lycium barbarum had thicker and larger of leaf than the aphid-resistant variety’Ningqi No.1’,and the high-resistant variety ’Ningqi No.1’ had higher wax content,deeper vascular bundles and thicker cuticle than the high-susceptible variety ’Ningqi No.10’.The correlation analysis between 6 physical characters and aphid number ratio showed that there was a correlation between the six physical traits and aphid number ratio,but the correlation was not significant,among them,aphid number ratio of different wolfberry varieties was positively correlated with thickness of leaf(R=0.937,P=0.063),area(R=0.567,P=0.433),and it was negatively correlated with wax content(R=-0.531,P=0.147),thickness of cuticle(R=-0.842,P=0.158),vascular bundle depth(R=-0.749,P=0.251),and thickness of lower epidermis(R=-0.422,P=0.578)in foliage.6.The differences in physiological and biochemical indexes of different wolfberry varieties and feeding stages were explored and analyzed.The results showed that there were significant differences in nutrient content,secondary metabolites content and protective enzyme activity of different wolfberry varieties before and after being eaten by A.gossypii.Before feeding,the content of secondary metabolites and protective enzymes were significantly lower than those of aphid-resistant varieties,while the nutrient content was higher than that of aphid-resistant varieties in aphid species.After feeding,with the increase of feeding time,the content of amino acids,soluble sugars,tannins,total phenols and other substances,as well as the activity of PPO and POD,showed a trend of increasing first and then decreasing,while the activity of SOD showed a trend of first increasing and then decreasing and then increasing and then decreasing.