The apple (Malus ×domestica Borkh.) cultivars Starkspur Supreme Delicious and Melrose were planted in 1987 on eight apomictic apple rootstock selections made in Germany by Dr. Hanna Schmidt and on M.7. Selections 2 [M. hupehensis (Pamp.) Rehd. parentage] and 8 [M. sieboldii (Regel) Rehd. parentage] were similar to M.7 in precocity, cumulative yield per tree, and yield efficiency, while the other selections with M. sargenti Rehd. in their parentage were slower to flower and had lower yields and yield efficiencies. Selections 2 and 8 tended to result in larger trees than M.7, while the selections with M. sargenti parentage were generally similar to M.7 in size. Except for trees on M.7 and selection 2, `Starkspur Supreme Delicious' developed more severe symptoms of internal bark necrosis (IBN) than did `Melrose', which normally does not show IBN. However, `Melrose' showed IBN symptoms on selections with M. sargenti parentage. IBN symptoms were positively correlated with leaf Mn concentrations. Influence of rootstocks on other nutrient elements, although significant, were small compared to the effect on Mn. A significant interaction occurred between cultivar and rootstock in their effects upon branch morphology, mostly because fewer flowering spurs and more vegetative spurs were observed on `Melrose' than on `Starkspur Supreme Delicious' when grafted on Selection 2. These apomictic selections offered no advantage over M.7 as rootstocks for apples.
David C. Ferree
Roger Kjelgren and Craig Spihlman
Limited root development of nursery stock in root-control bags facilitates harvest but without irrigation may predispose stock to water stress. The effect of bags and irrigation on growth and water relations of field-grown Malus sieboldii var. zumi were investigated following transplanting as large liners into a silty-clay soil. Predawn leaf water potential (ψ), and midday stomatal conductance (gs) and ψ, were measured periodically through the season. Late-season osmotic potential (ψπ), caliper, leaf area, and root growth were also measured. Non-irrigated treatments exhibited water stress during an extended mid-summer drought, as predawn ψ and particularly gs were less than irrigated treatments, resulting in lower vegetative growth and ψπ. For combined bagged treatments water relations did not differ, but leaf area, root growth, and ψπ, but not caliper, were less than non-bagged trees. Growth measurements and ψπ of non-irrigated bagged trees, however, were consistently lower but nonsignificant than the other treatments. Bag-induced root reduction can limit some top growth even with optimum soil water. Moreover, in terms of potential Type-II errors extrapolated over a conventional production cycle, trees grown in root-control bags in normally non-irrigated soils may be more susceptible to water stress and subjected to further cumulative growth limitation.
Wanmei Jin, Qiang Zhang, Sunzhong Liu, Qinping Wei, Wanmei Jin, Zongming Cheng, Xiaohui Xue, and Tingzhen Yang
. 134 228 235 Seemüller, E. Moll, E. Schneider, B. 2008 Apple proliferation resistance of Malus sieboldii -based rootstocks in comparison to rootstocks derived from other Malus species Eur. J. Plant Pathol. 121 109 119 Shao, K.J. Li, D.K. Zhang, Z
Ying Li, Liyi Zhang, Zhen Zhang, Peihua Cong, and Zong-Ming Cheng
-mildew-resistance gene Pl (1) from Malus robusta in cultivated apple Plant Breed. 114 530 534 Moriya, S. Iwanami, H. Takahashi, S. Kotoda, N. Suzaki, K. Yamamoto, T. Abe, K. 2009 Genetic mapping of the crown gall resistance gene of the wild apple Malus sieboldii Tree
Sogo Nishio, Masahiko Yamada, Yutaka Sawamura, Norio Takada, and Toshihiro Saito
quality traits in apple Tree Genet. Genomes 4 647 661 Moriya, S. Iwanami, H. Takahashi, S. Kotoda, N. Suzaki, K. Yamamoto, T. Abe, K. 2010 Genetic mapping of the crown gall resistance gene of the wild apple Malus sieboldii Tree Genet. Genomes 6 195 203
Gennaro Fazio, Yizhen Wan, Dariusz Kviklys, Leticia Romero, Richard Adams, David Strickland, and Terence Robinson
. Yamamoto, T. Abe, K. 2012 Aligned genetic linkage maps of apple rootstock cultivar ‘JM7’ and Malus sieboldii ‘Sanashi 63’ constructed with novel EST-SSRs Tree Genet. Genomes 8 709 723 Oraguzie, N.C. Yamamoto, T. Soejima, J. Suzuki, T. Silva, H.N.d. 2005