わい性および半わい性台木を利用したリンゴ'スターキング・デリシャス'樹における純生産量とその樹体内分配に及ぼす栽植密度の影響(栽培管理・作型)  [in Japanese] Effect of Planting Density on Net Production and Partitioning in 'Starking Delicious' Apple Trees on Dwarfing and Semi-dwarfing Rootstocks(Crop Production & Cropping Type)  [in Japanese]

純生産量(t乾重/ha/年)とその樹体内分配に及ぼす栽植密度の影響を無勢定状態のわい性および半わい性台木利用リンゴ'スターキング・デリシャス'樹を供試して検討した.個体年間生産量(⊿pn)と果実,葉,枝,幹および根の1樹当たり年間生産量(fd,ld,⊿pb,⊿ptおよび⊿pr)は,各台木樹とも栽植密度(p)の増加に伴って減少した.⊿pn,z(ld,⊿pb,⊿ptあるいは⊿pr)およびfdに関する密度効果は,それぞれ1/⊿pn=A_1p+B_1,1/z=A_2p+B_2およびfd=K' exp(-k'p)という関係式で表された.純生産量(⊿Pn)と葉,枝,幹および根の純生産量(Ld,⊿Pb,⊿Ptおよび⊿Pr)は,各台木樹とも栽植密度(p)の増加に伴って増加した.しかし,果実生産量(Fd)はM.26台木樹以外の台木樹では,それを最大にする最適栽植密度(p_<opt>)が存在した.⊿Pn,Z(Ld,⊿Pb,⊿Ptあるいは⊿Pr)およびFdに関する密度効果は,それぞれ1/⊿Pn=A_3+B_3/p,1/Z=A_4+B_4/pおよびFd=H'p/(A_1p+B_1)^<h'>という式で表された.葉,枝,幹および根への分配率(Ld/⊿Pn,⊿Pb/⊿Pn,⊿Pt/⊿Pnおよび⊿Pr/⊿Pn)は,各台木樹とも栽植密度(p)の増加に伴って増加したが,果実への分配率(Fd/⊿Pn)は減少した.Z/⊿Pn(Ld/⊿Pn,⊿Pb/⊿Pn,⊿Pt/⊿Pnあるいは⊿Pr/⊿Pn)とFd/⊿Pnに関する密度効果は,それぞれ1/(Z/⊿Pn)=A_5+B_5/pとFd/⊿Pn=K' exp(-k'p)という式で表された.果実生産量(Fd)と純生産量(⊿Pn)の関係は,式Fd=-a_1(⊿Pn)^2+b_1(⊿Pn)+c_1で表され,果実生産量(Fd)と果実への分配率(Fd/⊿Pn)の関係は,式Fd=-a_2(Fd/⊿Pn)^2+b_2(Fd/⊿Pn)+c_2で表された.純生産量(⊿Pn)と果実への分配率(Fd/⊿Pn)の相対的関係を⊿Pn/(Fd/⊿Pn)と定義して,果実生産量(Fd)と⊿Pn/(Fd/⊿Pn)をlog〜log座標に図示すると,両者の関係は(第6図)はlog Fd〜logp曲線(第2図)と同様のパターンを示した.以上の結果から,果実生産量に関する密度効果は,栽植密度によって⊿Pn/(Fd/⊿Pn)が変化し,それによって果実生産量が変化する現象と考えられる.

The effect of planting density (330-3178 trees/ha) on net production (t DW/ha/y) and partitioning was studied in 11 to 13-year-old 'Starking Delicious' apple trees on M.9, M.26, M.7 and MM. 106 without pruning. On all rootstocks, individual annual dry matter production (⊿pn) and annual dry matter production per tree of fruit (fd), leaf (ld), branch (⊿pb), trunk (⊿pt) and root (⊿pr) decreased as planting density (p) increased. The density effects on ⊿pn, z (ld, ⊿pb, ⊿pt or ⊿pr) and fd could be represented by the following equations, respectively: 1/ ⊿pn=A_1p+B_1, 1/z=A_2p+B_2, and fd=K exp (-kp). On all rootstocks, net production (⊿Pn) and net production of leaf(Ld), branch (⊿Pb), trunk (⊿Pt) and root (⊿Pr) increased as planting density (p) increased, but on three rootstocks excluding M.26, the net production of fruit (fruit production: Fd) was maximized at the optimum planting density (p_<opt>). The density effects on ⊿Pn, Z (Ld, ⊿Pb, ⊿Pt or ⊿Pr) and Fd could be represented by the following equations, respectively: 1/ ⊿Pn=A_3+B_3/p, 1/Z=A_4+B_4/p, and Fd=H'p/(A_1p+B_1)^<h'>. Partitioning ratio into leaf (Ld/ ⊿Pn), branch (⊿Pb/ ⊿Pn), trunk (⊿Pt/ ⊿Pn) and root (⊿Pr/⊿Pn) increased as planting density (p) increased, but that into fruit (Fd/ ⊿Pn) decreased. The density effects on Z/ ⊿Pn (Ld/ ⊿Pn, ⊿Pb/ ⊿Pn, ⊿Pt/ ⊿Pn or ⊿Pr/ ⊿Pn) and Fd/ ⊿Pn could be represented by the following equations, respectively: 1/ (Z/ ⊿Pn)=A_5+B_5/p and Fd/ ⊿Pn=K' exp (-k'p). The relationship between fruit production (Fd) and net production (⊿Pn) could be represented by the following quadratic function: Fd=-a_1 (⊿Pn)^2+b_1 (⊿Pn)+c_1. The relationship between fruit production (Fd) and partitioning ratio into fruit (Fd/ ⊿Pn) could be represented by the following quadratic function: Fd=-a_2 (Fd/ ⊿Pn)^2+b_2 (Fd/ ⊿Pn)+c_2. The relative relation between the net production (⊿Pn) and the partitioning ratio into fruit (Fd/ ⊿Pn) was defined as ⊿Pn/ (Fd/ ⊿Pn), and the relations between fruit production (Fd) and ⊿Pn/ (Fd/ ⊿Pn) plotted on the log〜log coordinates (Fig. 6) showed the same pattern as the log Fd〜logp curves (Fig. 2). From these results, it was suggested that the density effect on fruit production is a phenomenon that ⊿Pn/ (Fd/ ⊿Pn) changes with planting density, and, as a result, fruit production changes.