Effectiveness of PGPR for improving nutritional quality of red lettuce cultivars

The purpose of this experiment was to study the effectiveness of PGPR dosages applied for improving nutritional quality (anthocyanins, carotenoid and total chlorophyll) of two red lettuce cultivars. The experiment was conducted in Dadaprejo Village, Junrejo District, Batu in July - August 2017. This was a factorial experiment arranged in Completely Randomized Block Design which consisted of 2 factors. The first factor was two red lettuce cultivars consisted of Red Rapid (V1) and Lollo Rossa (V2). The second factor was a PGPR dosage consisted of 6 levels: without PGPR (P0), 100 ml PGPR (P1), 150 ml PGPR (P2), 200 ml PGPR (P3), 250 ml PGPR (P4) and 300 ml PGPR (P5). Parameters observed were anthocyanins, beta-carotene and total chlorophyll content at 25, 35 and 45 days after planting (dap). The result showed that there was interaction between red lettuce cultivars and various PGPR dosages on chlorophyll content at 45 dap. Combining Lollo Rossa with 250 ml PGPR produced the highest chlorophyll content. On the other hand, no interaction found between red lettuce cultivars and various PGPR dosages on carotenoid and anthocyanins content. However, cultivars and PGPR dosages had significant effect on anthocyanins content respectively, while only cultivars significantly affected carotenoid content. Red Rapid cultivar outperformed Lollo Rossa on both carotenoid and anthocyanin content observed. Highest anthocyanin content obtained by applying 250 ml PGPR.