EFFECTS OF DROUGHT ON CHLOROPHYLL FLUORESCENCE IN POTATO (SOLANUM-TUBEROSUM L) .2. RELATIONS BETWEEN PLANT-GROWTH AND MEASUREMENTS OF FLUORESCENCE

Relations between measurements of the slow kinetics of chlorophyll fluorescence and growth and yield were examined in seven potato genotypes grown either fully irrigated or droughted from the time of plant emergence. Drought reduced total dry matter production and yields and increased tuber dry matter concentration. Drought increased harvest index in cv. Spunta, but decreased it in cv. Pentland Crown. Total dry matter production was correlated with each of constant fluorescence, variable fluorescence and the half life of the decay in variable fluorescence. These correlations were determined largely by the effect of treatment, and did not discriminate effectively between genotypes within a treatment.