| Mulberry germplasm resources are widely distributed in the intermountain basin of eastern Tianshan Mountain,with various types,high nutritional value of mulberry fruit and unique variety characteristics in Xinjiang.In this study,through the investigation and collection of mulberry germplasm resources in the intermountain basin in the east of Tianshan Mountain,the geographical distribution characteristics,climatic water and heat conditions were analyzed,and the phenotypic characters and nutritional quality of mulberry fruits were quantified.the variation and diversity of mulberry resources were discussed,and multivariate statistical analysis was used to distinguish the difference characteristic indexes and classify the mulberry resources in order to clarify the population species structure.The germplasm with breeding potential was selected.The main results are as follows:（1）According to the investigation of mulberry germplasm resources in the intermountain basin in the east of Tianshan Mountain,a total of 114 mulberry trees were measured,including 17 ancient trees,35 specimens and 23 preserved in different places.The investigation results show that there are more mulberry resources such as white mulberry,black mulberry and medicinal mulberry in the intermountain basin in the east of Tianshan,while the proportion of pink mulberry and purple mulberry resources is relatively small;the characteristics of each mulberry species are distinct,and the phenotypic differences of local species are not obvious,but there are significant differences among individual plants;23 mulberry trees with excellent characters were collected and the branches with full buds were preserved in different places.（2）According to 18 climatic hydrothermal factors,it is known that the intermountain basin in the east of Tianshan Mountain has the climatic characteristics of sufficient heat,drought and little water,and the ecological adaptability of mulberry resources can be obtained from a wide range of limit and optimum range.The geographical longitude,latitude and altitude of mulberry resources are significantly related to climatic factors,which have a profound impact on mulberry distribution,growth,quality and phenotypic differences,thus promoting the genetic diversity of mulberry resources.The climatic factors that play a key role in the geographical distribution of mulberry germplasm resources in the intermountain basin of eastern Tianshan are poor temperature,moisture and annual air temperature.the coldest monthly minimum air temperature and annual average air temperature index can be used as breakthroughs to guide mulberry cultivation,selection of suitable introduction areas and comprehensive utilization.（3）The phenotypic diversity of mulberry germplasm resources in the intermountain basin of eastern Tianshan Mountain is high,and the variation of each character is extremely rich.There were significant correlations among 13 quantitative characters in 7 groups and 40 groups,which indicated that most of the characters had extremely significant correlation,and there were weak correlations among other indexes in different degrees.The key indexes affecting the classification of mulberry resources are fruit longitudinal diameter,leaf length,bud spacing,pitch and lenticel number.The 114 germplasm resources were divided into 5 groups by cluster analysis,and the most obvious intuitive classification feature was the difference of fruit color.According to the comprehensive evaluation,the top ten germplasm numbers are HM17,TLF16,TLF37,TLF27,TLF56-3,TLF4,TLF28,HM10,TLF52 and SS15.（4）There are some differences in nutritional quality among different mulberry fruits,and the coefficient of variation of basic quality index changes greatly,while the fluctuation of active substances is small,but the average content is high.There was significant correlation among the quality indexes in 23 groups and extremely significant in 17 groups.According to cluster analysis,different mulberry fruits were further divided into three groups:TLF1（medicinal mulberry）,TLF16（black mulberry）,SS13（white mulberry）,HM11（purple mulberry）and SS7（pink mulberry）.OPLS-DA analysis showed that the difference indexes were total phenols and total flavonoids.According to the mathematical model of comprehensive evaluation:Fensemble=0.541F1+0.261F2+0.197F3,the order of comprehensive score from big to small is TLF1（medicinal mulberry）,SS13（white mulberry）,TLF16（black mulberry）,HM11（purple mulberry）and SS7（pink mulberry）. |
