テンサイ一代雑種およびそれらの親系統の個葉における気孔コンダクタンス，蒸散速度および純光合成速度の系統間差

抄録

　To investigate the effect of surface temperature (T_c) differences and to clarify the plant physiological differences between F₁s (F₁：First filial generation) and their parents, we analyzed the differences of the stomatal conductance (g_s), transpiration rate (E) and net photosynthesis rate (A) among six sugar beet genotypes.
　Three of the genotypes: “NK195BR”, “NK235BR” and “NK388” were tested as parents, while the other three “NK235BR×NK195BR”, “NK195BR×NK388” and “NK235BR×NK388” were tested as F₁s. From the comparison of the mean T_c value of six genotypes measured at 6 hours (from 10:00 to 16:00), the results, in descending order of their value, showed “NK235BR” > “NK388” > “NK195BR” > “NK195BR×NK388” > “NK235BR×NK195BR” > “NK235BR×NK388”.
　To analyze the relationship between T_c and plant physiology, g_s, E and A were measured at six times during mid-growing season. As a result, g_s and E had a significant varietal difference among the six genotypes every measurement. Both the g_s and E values of F₁s had a trend higher than those of their parents. A comparison between g_s and the differences between T_c and air temperature (ΔT), revealed that the two had a negative liner correlation such that the higher the g_s was, the lower the ΔT. On the other hand, A had a significant varietal difference depending on the day. However, there was no clear relationships to indicate that F₁s had a trend higher than those of their parents.
　In relation to yield component and plant physiological properties, root weight and sugar yield were significantly correlated with both of g_s and E and had no significant correlation with the sugar content. On the other hand, A had no significant correlation with root weight, sugar content or sugar yield.