RESPONSE OF VERMICOMPOST ON YIELD AND PROCESSING QUALITY OF POTATO DERIVED FROM TPS AS INFLUENCED BY ITS SIZE

Abstract

The experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka-1207, during the period from November, 20 IS to April, 2016 to assess the effect of vermicompost and tuber size on the yield, specific gravity, dry matter, starch, sugar content, antioxidant and polyphenol activity of potato. The experiment was consisted of two factors, i.e., factor A:- Vermicompost level (Vm-4): Vml: 0 t ha", Vm2: 3 t ha", Vm3: 6 t ha" and Vm4: 9 t ha"; factor B:- Tuber size (T-S): r.:S-10 g, T2: 10-20 g, T3:20-30 g, T4: 30-40 g and r; >40 g. Experiment was conducted in a split-plot design with three replications. Vermicompost levels were assigned to main plots and tuber sizes were to sub plot. Low yield and inferior quality are crucial bottleneck for potato production in Bangladesh. The application of vermicompost may enhance the yield and quality of potato. The present research exhibited that vermicompost had significant effect on most of the yield and quality contributing parameters investigated under present experiment. Results showed that yield and other processing quality parameters increased with increasing vermicompost level irrespective of tuber size. Among the twenty (20) treatment combinations, vermicompost at the rate of9 t ha! with tuber size >40 g produced the maximum yield (31.33 t ha') and exhibited the highest firmness (44.349 N), specific gravity (1.084 g cm"), dry matter (22.77%), starch (23.81 mg g" FW), antioxidant (478.84 Trolox IlMol 100 g" FW), polyphenol (96.133 GA mg 100 g-1 FW), flesh color (L *- 7S.60; a*- 11.76; b*- 24.96) and the lowest reducing sugar (0.1020 mg g-1FW) and non-reducing sugar (0.2947 mg g-1FW). In respect of ambient storage condition; firmness, specific gravity, dry matter, starch, skin color and flesh color decreased with increasing storage time while weight loss, total soluble solid (TSS) increased with increasing storage time. In case of total soluble solid (TSS), reducing sugar, non-reducing sugar, antioxidant and polyphenol content slowly increased with increasing storage time up to 40 days after storage (DAS) and thereafter sharply increased and finally became nonsuitable for both table and processing purpose. Therefore, present study suggests that potato growers may use vermicompost for increasing yield and improving processmg quality of potato and can store potato up to 40 DAS at ambient condition.