Clustering Analysis On Root Traits And Developmental Difference Between Seminal And Nodal Roots Of Leading Wheat (Triticum Aestivum L.) Cultivars In Henan Province

Using twenty-three leading wheat cultivars currently grown in Henan Province as test materials, root traits were comprehensively studied by pot experiments and the root-guiding method. The study were aimed at making clear root characteristics and developmental difference between seminal and nodal roots of the leading cultivars so that theoretical references could be provided for reasonable utilization of the cultivars and for regulation of root system in order to realize high-yield,good-quality and high-efficiency production as well. The main results are as follows:(1) Clustering analyses were made on main morphological and quantitative root traits of the leading wheat cultivars. The findings showed that roots of these cultivars could be divided into three categories: the developed, the comparatively developed, and the underdeveloped root system. The developed root system was characteristic of more nodal roots per plant, and bigger root volume and dry root weight per plant.(2) Clustering analyses were also made on root physiological traits of the leading cultivars. The results showed that root system of the cultivars could be divided into three categories: the high-level, the medium-level, and the low-level physiological ability. Under the conditions of the present study, plants with the medium-level root physiological ability achieved the highest grain yield.(3) Differences in morphological and quantitative traits between seminal and nodal roots of the leading cultivars were made clear. The results from six representative wheat cultivars showed that difference in morphological and quantitative traits between seminal and nodal roots was significant at 5% level. Difference in morphological and quantitative traits between seminal and nodal roots during the whole growing period behaved as: growth and dry weight of seminal roots were dominant in early growing period, with advance in the growing period, growth and dry weight of nodal roots were gradually dominant, while in late growing period nodal roots were still parts dominant in growth. (4) Differences in physiological traits between seminal and nodal roots of those six cultivars were also clarified. The findings indicated that physiological characteristics traits of seminal and nodal roots were significantly different at 5% level. During the whole growing period, physiological potential of nodal roots was always higher than that of seminal roots. Contents of total nitrogen and sugar were higher in nodal roots than those in seminal roots, before flag leaf expansion stage, while after the stage contents of total nitrogen and soluble sugars in seminal roots were gradually dominant.(5) Relationships between root traits and grain yield and its components were elucidated. The results showed that correlations between seminal and nodal roots per plant, dry weight of seminal and nodal roots per plant, root vigor of seminal and nodal roots, and content of total nitrogen and soluble sugars in seminal and nodal roots and grain yield and its components were significant at 5% level.