0023-6152

AA00697606

23759

Unrefereed

0023-6152

AA00697606

This investigation was conducted to elucidate the characteristics of dry matter and yield production of sweet potatoes (Zpomoea batatas (L.) Lam.) under field conditions. Two cultivars (Koganesengan and Minamiyutaka) were used as materials. The materials were grown under ordinary field cultivating conditions. Growth analysis was periodically done throughout the whole growth duration. Further, the relations of climatic factors to dry matter production and yield were made by correlation analysis. Dry weight of total and tuberous root (yield) of Koganesengan were 2,047g DW/m^2 and 1,754 g DW/m^2, respectively. These values were larger than those of Minamiyutaka. Its harvest index was 84.6 %. The growth period of this crop was divided into two from the variation of LA1 with growth. The first half period was the stage of LA1 increase and the second half was that of maintaining matured LA1 (canopy). In both cultivars the maximum LA1 reached about 5.0 and optimum LA1 was 3.67. Further CGRmax was 20.66 g DW/m^2/day. CGR in the first half period depended highly on LA1 through mean air temperature and in the second half period on NAR through mean solar radiation. Yield growth rate (YGR) in the second half period was also more influenced by NAR through mean solar radiation than air temperature. Lower air temperature, within favourable range of growing temperature, was good for YGR.