Effects of Planting Density on Growth of the Andigena Strain (S. tuberosum ssp. andigena)

[摘要] In recent years, Andigena (S. tuberosum ssp. andigena) has attracted the attention of potato breeders as a material for improving yield capacity. The autors reported that one of Andigena strains (W553-4) had high yield capacity and an efficient canopy structure for light transmission. In this experiment, W553-4 was planted to estimate its characteristics of dry matter production and canopy structure at the three population densities (Table 1). 1. W553-4 had large dry weight of stem, root and stolon, and later tuber initiation by 15 to 20 days compared with Norin N0.1. The tuber initiations at the medium and the high density, however, were earlier by several days than that at the low density, and after the middle of August, their total dry weights were considerably large (Fig. 1). In addition, W553-4 showed a tendency that at the higher density, percentages of tuber dry weight were high and those of shoot (leaf and stem) dry weight were low (Fig. 2). 2. The peaks of crop growth rate (CGR) and tuber growth rate (TGR) for W553-4 were later than those for Norin No. 1 (except that of CGR at the low density), and values at the medium and the high density were rather high. W553-4 had large differences in leaf area index (LAI) among densities, and showed rapid decline of net assimilation rate (NAR) at the early growing season (Fig. 3). 3. For photosynthetically-active radiation intercepted by crops during the experimental periods (ΔPAR) and efficiency of dry matter accumulation per ΔPAR (EPAR), the medium density for both W553-4 and Norin No. 1 was high (Table 2). As for each experimental period, CGR was correlated positively with ΔPAR during emergence to the tuber initiation, and also closely related to EPAR during all periods (Fig. 4). 4. Canopy structures for W553-4 were efficient for light transmission compared with those for Norin No. 1. Large amount of leaf area distributed in lower layers at the low density, and leaf area at the medium and the high density distributed uniformly over all layers with small light extinction coefficient (K) values (Fig. 5). For compound leaf area, W553-4 had large differences among densities, and considerably large leaves existed at the low density (Fig. 6).

[学科分类] 农业科学（综合）