Establishment Of Cold Resistance System Of Pepper And Screening Of Materials

Pepper?Capsicum annuum L.?belongs to solanaceae family,which has rich nutritional value and is one of the favorite vegetables.Because of the characteristic of pepper thermophilia and low temperature effect the metabolism of pepper,the cultivation scope of pepper is limited,Therefore,the experiment materials of P70,AA5,P90,EC,Qiemen,P10,CK7 was provided by the pepper research group of horticulture college of Northwest A&F university.The identification equations of cold resistance were established by studying the characteristics of bud stage and seedling stage,The cold resistance of different pepper germplasm resources?P59,ZD24,CK6,B35,R15,R14,B48,R10,CK18,CK13,B6,P126,R22,R9,B41,CK11,R20,B49,R25,B8-1?was screened by using the cold resistance equation at bud stage and seedling stage.In order to provide good germplasm resources for pepper cold resistance breeding,the materials with good comprehensive characters and good cold resistance were selected.The main results obtained are as follows:1.By combining the 20?germination rate,15?germination rate,20?germination rate potential,25?germination index,20?germination index,15?germination index,20?radicle growth rate,25?vitality index,20 vitality index,15?vitality index and the mean value of the membership function of 7 tested pepper at the budding stage,Stepwise regression analysis showed that:The equation of pepper cold resistance at the budding stage is y=-1.14868+0.77205×x₄?p=0.001<0.01,x₄ represent 20?germination index?.A large number of germplasm resources can be screened by cold resistance equation in bud stage.2.The cold injury index of P70 and AA5 was under 0.4,and had the strongest cold resistance.The cold injury index of P90,EC and CK7 is lower than 0.6.The chilling injury index of Qiemen and P10 reached above 0.6,which was a pepper variety with weak cold resistance.This result is consistent with the screening result of cold resistance equation in bud stage.3.Through the pepper seedlings at low temperature we know:The P70 and AA5 relative germination rate is higher,its strongest cold resistance,its strong and cold resistance varieties,P90,EC and P10 relative germination were lower,its cold resistance varieties,CK7 and Qiemen has the lowest germination rate and the not cold resistance,he results are consistent with the results of cold resistance equation selection at bud stage and cold injury index at seedling stage.4.According to the mean value of the comprehensive membership function of the seven pepper physiological indexes tested,we konow:the cold resistance of the seven pepper varieties is P70>AA5>P90>P10>EC>CK7>Qiemen.This result is consistent with the cold resistance equation screening at the bud stage,cold injury index at the seedling stage and seedling emergence at low temperature.5.Through comprehensive seven selected chili seedling?day/night?10?/5?conductivity content,malondialdehyde content in 10/5?,chlorophyll content in 10/5?,proline content in 10/5,chlorophyll content in 20?/15?,malondialdehyde content in15?/10?and membership function the indicators,the stepwise regression analysis shows that the equation of pepper seedling cold resistance is Y=0.32541+1.34822x?p=0.0013<0.01,x represents 10?/5?of severe chlorophyll content under low temperature stress?.6.According to the comprehensive analysis of the cold resistance equation at the bud and seedling stages,the cold resistance of the 27 pepper varieties are:with strong cold resistance are P59,ZD24,CK6,B35,R15,R14 and P70.Cold resistance of the general variety are B48,R10,CK18,CK13,B6,P126,R22,R9,B41,AA5,EC,P90,P10.not cold resistant varieties are CK7,Qiemen,CK11,R20,B49,R25 and B8-1.