Differences of the canopy surface temperature between F1s and their parents in sugar beet （Beta vulgaris L. ssp. vulgaris）

Abstract

To investigate the effect of heterosis between F1s (F1:First filial generation) and their parents, we investigated the differences of canopy surface temperature ( T c ) 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. The diurnal variation of T c was maximal between 10:00 and 14:00. The maximum difference among genotypes was about 2.7 ℃ in daytime and the T c of “ NK195BR × NK388 ” showed the lowest among the other genotypes in 103 days after transplanting. The differences of T c among genotypes increased with increasing vapor pressure deficit. Comparing the 6 hours mean T c value of six genotypes from 10:00 to 16:00 and in descending order of its value, the results showed “ NK388 ” > “ NK235BR ” > “ NK195BR ” > “ NK235BR × NK195BR ” > “ NK235BR × NK388 ” > “ NK195BR × NK388 ” . Although there was a trend that the yield of F1s was higher than that of their parents with high T c , it is necessary to clarify the relationship between T c and yield in the future.