水稲の葉層構造と収量の解析 : 第1報穂重型, 穂数型両品種について作期, 栽植様式および栽植密度を異にした場合

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Two lowland rice cultivars, Yamahoushi (panicle-weight type) and Kinki No. 33 (panicle-number type), were grown in three cropping seasons (early, normal and late plantings) at three levels of planting density (40, 20 and 10 hill/m^2) in 1968. Yamahoushi was square-planted and Kinki No. 33 was planted both in square and in low. Canopy structure was characterized by (1) total biomass of the aerial parts of plant and (2) vertical distribution of leaf blade determined by "the stratifying clip method" and was expressed as the percentage of leaf dry weight in each stratum to the total leaf dry weight. Sampling was done at four growth stages, that is, the active-tillering, young panicle formation, heading and maturing stage, respectively. The canopy profile (the space between the soil surface and the top of plants) was evenly divided into five strata and the stratifying clip method was applied to each stratum. The relationships between yield and total biomass and those between yield and vertical distribution of leaf blade were examined by principal component analysis. The first and second component axes obtained by the analysis (Table 1) were rotated to derive axes which are easier to understand and enable a more convenient comparison of the contributions of the strata (Table 2, Fig. 1). In general, the angle (degree) of rotation of axes on a plane, say θ is difined as θ=45°-ε/2, which maximizes f(θ) given by f(θ)=Σ^^p__<i=1> (α_iA_icsθ+α_iB_i sin θ)^2+Σ^^q__<j=1>(-β_jA_j sin θ+β_jB_j cos θ)^2. The formula for the parameter ε in the former equation is ε=tan^<-1>[Σ^^p__<i=1>(α_iA_i)^2+Σ^^q__<j=1>(β_jB_j)^2-Σ^^p__<i=1>(α_iB_i)^2-Σ^^q__<j=1>(β_jA_j)^2] ÷(2Σ^^p__<i=1>α_i^2A_iB_i-2Σ^^q__<j=1>β_j^2A_jB_j), where subscript i (=1, 2,‥, p) designate the variables to be located on or approached to one of the rotated axes, subscript j. (=1, 2, ‥, q) showing the variables to be located on the other axis. Symbols A_i and B_i stand for the factor loadings of variable i for the first and second principal components, respectively, α_i being the weight which is determened according to agronomical importance. Symbols A_j, B_j and β_j are similarly defined for variable j. In the present experiment, the group of variable i consists of the two leaf strata, No. 2 and 4, and the group of j contains only one leaf stratum, No.3. The weights α_i and β_j were assumed to be unity for brevity. θ was calculated to be -8.62°. Using the factor scores in the two axes derived by the rotation (F_1 and F_2), the vertical distribution of leaf weight percentage (leaf stratified structure) and the relation between yield and these scores were investigated. The results are summarized as follows: 1. As F_1 score increased, the leaf weight percentage of the upper stratum increased, whereas that of the lower stratum decreased. As F_2 score increased, the leaf weight percentage of the middle stratum decreased. After rotation of the axes, the tendencies found in these factors were clearer than in the original principal components (Fig. 2). These two factors explained approximately 90% of total variation (Table 2). 2. Leaf weight percentage in the upper stratum became larger as plants grew. At the heading stage the percentage in the middle stratum became larger in both varieties grown in early and normal seasons. This was more evident in Kinki No. 33 than in Yamahoushi (Fig. 3). 3. The weakness of the correlation between F_1 or F_2 score and top dry weight suggests that these parameters are relatively independent of each other. 4. The correlation between yield (hulled rice) and top dry weight at each growth stage was shown to be significant in most treatments. The correlation was highly significant in all treatments except four, i.e., both varieties grown in early season and row-planted Kinki No. 33 grown in late season (Table 4). 5. The correlation between yield and F_1 or F_2 score at e
日本作物学会の論文
1983-12-05

水稲の葉層構造と収量の解析 : 第1報穂重型, 穂数型両品種について作期, 栽植様式および栽植密度を異にした場合

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水稲の葉層構造と収量の解析 : 第1報 穂重型, 穂数型両品種について作期, 栽植様式および栽植密度を異にした場合

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水稲の葉層構造と収量の解析 : 第1報穂重型, 穂数型両品種について作期, 栽植様式および栽植密度を異にした場合