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BULB YIELD AND QUALITY OF ONION (Allium cepaL.) AS AFFECTED BYSOWING TIME AND POTASSIUM SUPPLY
- The two experiments were conducted at the Horticulture Department, Yezin Agricultural University from October 2010 to April 2012 in order to examine the effects of various levels of K supply and different sowing times (ST) on yield and quality of onion. Two ST (31 October, 21 November) and four K levels (0, 50, 100, 150 kg K2O ha-1) in experiment I and three ST (7 November, 21 November, 5 December) and three K levels (0, 50, 100 kg K2O ha-1) in experiment II were laid out as main plot and sub-plot factors respectively. The growth parameters were recorded weekly and the yield parameters were measured at two harvests in experiment I and five harvests in experiment II. The quality parameters were evaluated at final harvest times and post harvest weight loss during the one month storage for both experiments. In experiment I, the plants heights from 21 November ST (farmers’ sowing time) showed higher than that from 31 October ST. The significantly higher values of shoot weight, bulb weight and bulb diameter but lower bulbing ratio were recorded in plants of 31 October ST in comparison to 21 November ST at 91 days after transplanting (DAT). Consequently higher weight loss % was observed in the onion bulbs from 31 October ST after one month of storage. Regarding the K supply, the plants treated with high K levels (100 and 150 kg K2O ha-1) produced the more number of leaves along the growth period, and showed the higher values in bulb weight, bulb diameter, bulb N and protein contents, shoot K content and total soluble solid (TSS %) at final harvest (91 DAT) and lower weight loss % at 28 days after storage as compared to control. Among the K levels, 100 kg K2O ha-1 revealed the significantly higher bulbing ratio than control. In experiment II, the plants from 7 November ST showed the maximum values of all vegetative parameters and bulb weight, but the minimum values of bulbing ratio, bulb K and TSS %. The plants from 5 December ST showed the minimum values of leaf number at 8 weeks after transplanting, shoot weight, bulb weight, bulb diameter and neck diameter but maximum bulbing ratio and bulb K contents at 97 DAT. Post harvest weight loss % was the highest from 21 November ST and the lowest from 5 December ST. Regarding the K supply, the x highest value of shoot weight and the lowest weight loss % was observed in the treatment of 50 kg K2O ha-1. The highest bulbing ratio and bulb K content was obtained from the treatment of 100 kg K2O ha-1.
- Yezin Agricultural University