Search Results
Sequencing amplification fragments produced using simple-sequence repeat (SSR) primer pairs pchgms2 and UDP96008 in `Dayezhugan' japanese apricot showed that SSRs obtained included a microsatellite locus originally identified in peach. The microsatellite sequence homogeneity between UDP96008 in japanese apricot in this study and UDP96008 in the peach in GenBank was 98%. Twenty-four japanese apricot genotypes originating in diverse geographic areas had been identified with 14 SSR primer pairs developed in different species of Prunus. In total, 129 alleles were obtained and per primer pairs detected 2.5 alleles on the average. The results from cluster analysis showed that the genetic distance between `Nanhong' and `Zhonghong' was the closest, and cultivars from China and from Japan could not be separated completely.
Understanding of root growth patterns and architecture of apple (Malus ×domestica Borkh.) trees is very important for commercial apple production. Most commercial apple trees are usually a grafted complex consisting of the scion and the rootstock, each of which is a different genotype. Recently, rootstocks of dwarf tree species have been used extensively to meet the convenience in management; however, this practice appears to negatively impact root development. Using minirhizotrons, we investigated root dynamics, root spatial distribution, and shoot growth in ‘Red Fuji’ scion grown: 1) directly on dwarf and vigorous root stocks and 2) on a dwarf root stock placed in between the non-dwarf scion and non-dwarf rootstock (hereinafter referred to as an interstem). The results showed that: 1) one or two peaks in total root length density (TRLD) were observed in each scion/rootstock combinations every year; 2) the greatest TRLD peaks were always observed in between May and December. The peaks of shoot growth were always asynchronous with that of white root length density; 3) compared with scion/vigorous rootstock combinations, inserting a dwarfing interstem between the scion and vigorous seedling rootstock reduced the TRLD; 4) scion/vigorous rootstock combinations had a relatively deep, widespread and large root system. Scion/dwarfing rootstock combinations had a root system distributed in a small region; and the root systems of scion/dwarfing interstem/vigorous rootstock combinations tended to be intermediate between those of scion/vigorous rootstock and scion/dwarfing rootstock. This implies that the insertion of interstems altered the root architecture by not only the quantity of roots, but also the spatial distribution.