Genetic Diversity Analysis Of Phenotypic Traits And Comprehensive Assessment Of Tuber Quality In Introduced Potato Germplasm Resources

Potato belongs to foreign crop in China.Due to the lack of germplasm resources and the narrow genetic basis of germplasm,the introduction of potato germplasm from abroad and comprehensive assessment is an effective way to enrich germplasm resources in China.In this study,the genetic diversity of phenotypic traits in 119 potato clones introduced from Peru International Potato Center was analyzed.On the basis,we analyzed the relationship between plant architecture and tuber yield,and the relationship between canopy-air temperature difference and drought tolerance.The color qualities and texture properties of potato tubers were also evaluated.The main results were as follows:1.The genetic diversity of phenotypic traits in 119 introduced potato clones was analyzed using Shannon-Wiener's diversity index.The results showed that there existed differences in the diversity index and variation coefficient.The range of variation coefficient was 10.52-69.91,and the variation coefficient of yield per plant reached maximum.The range of diversity index was 1.56-4.37,and the diversity index of growth period reached maximum.2.The high and stable yield characteristics of germplasm resources were analyzed.The results showed that CIP393228.67 and CIP385561.124 in arid area and CIP304350.95,CIP392797.22,and CIP388615.22 in semi-arid area exhibited high and stable yield characteristics.3.There was no direct correlation between plant growth habit and tuber yield.The high yield of potato is formed from the interaction of each plant architecture traits,the nature plant height,erectness coefficient and drooping angle in the plant architecture traits were significantly correlated with the average tuber weight.In the 119 introduced potato clones,the plant erectness coefficient of high-yield germplasm type were significantly increased by14.10%-22.47%than that of other yield types.In the basal internodes length trait,the 4^th,5^thh and 6^th basal internode lengths of high-yield germplasm type were higher than other yield types.The angle between leaf and stem was decreased from base to top of main stem.The fifth angle is 5.56°less than the fourth angle,and the sixth angle is 6.01°less than the fifth angle.The average drooping angle of high-yield germplasm type was largest,which was significantly increased by 8.26%and 7.40%than the middle-low-yield germplasm type and low-yield germplasm,respectively.This plant architecture characteristic could avoid the plants or plant leaf to cover each other,improve photosynthesis efficiency,and achieve high yield.4.The plant phenotypic traits and photosynthetic physiological indexes and canopy-air temperature difference in these introduced potato clones were determined,and the drought tolerance was evaluated.The results indicated that the canopy-air temperature difference,transpiration rate and stomatal conductance were mostly sensitive to drought stress.The canopy-air temperature difference was significantly different in different potato clones under semi-arid and semi-humid environments.The drought tolerance coefficient of canopy-air temperature difference showed significantly positive correlation with the drought tolerance coefficient of plant phenotype and photosynthetic physiological indexes.It was suggested that the canopy-air temperature difference can be used as the identification index of potato drought resistance.The canopy-air temperature difference is an effective indicator to evaluate potato drought tolerance by using infrared thermometers,which could provide theoretical basis for the research of potato drought tolerant breeding.5.When tubers stored at 25?for 120 d,the changes of tuber and flour color of these introduced potato clones reached maximum.The effect of low-temperature?4??storage environment on tuber and flour color was greater than high-temperature?25??storage environment within 60 days.However,the low temperature storage environment has an inhibitory effect on tuber and flour color change within 120 days.During storage,the change of tuber color was significantly correlated with the soluble sugars and reducing sugar content in tubers.The higher the soluble sugars content in tuber,the darker the glossiness of flour.6.There was significant correlation between the starch content in potato tubers and the extrusion force and adhesive force of potato puree.These potato germplasm materials had different tuber and potato puree texture characteristics,which could be evaluated and screened for different processing purpose.