Effect of Plant Spacing on Big Onion (Allium Cepa L.) Yield in Yala Season
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Date
2013
Journal Title
Journal ISSN
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Big onion (Allium cepa L.) is an essential condiment in Sri Lankan diet so it is cultivated in Sri
Lanka. It mainly grows in Matale, Anuradhapura, Polonnaruwa, Kurunegala districts and
Mahaweli H zone. Pusa red, Rampure, Agri found light red, Kalpitiya selection, N53 and Nasic
red are the recommended varieties for Sri Lankan conditions considering the factors such as
high yield, seed setting ability, storage adaptability, pungency and color etc. Local production of
big onion, which is approximately 61,037 MT per year, is not sufficient to meet the annual
demand of big onion approximately in between 200,000 - 220,000 MT per year (Department of
Census and Statistics, 2011). The major constraint to improve the productivity of big onion in
Sri Lanka is the unavailability of good quality seeds of recommended varieties in adequate
quantities (Mettananda, 2006). In addition, the poor quality of imported seeds from India is
another constraint to enhance the big onion production. Poor quality seeds are characterized by
poor germination and poor bulb formation ability and poor quality seeds will result the bulbs
which show high thick neck percentage and low yield (Edirimanna, 2003). Minimizing the land
area devoted for big onion seed production is a challenge and one way to overcome this
challenge is to explore the possibilities of increase in plant density by decreasing plant spacing
without affecting seed yield. The objective of the present study was to study the effect of
reduction in plant spacing on big onion seed yield of variety Agri found light red which is
popularly cultivated in Sri Lanka.
Methodology
This experiment was conducted at the big onion cultivation site of CIC Agri Busisesses at
Palwehera, Dambulla from May 2013 to September 2013.Two plant spacings; 17.78 cm×17.78
cm and 15.24 cm×15.24 cm were used in the experiment which was laid out in a Completely
Randomized Block Design (CRBD) with 10 replicates. Agri found light red variety was used to
assess the final seed yield of onion.
Planting beds were prepared in size 1 m × 3 m. Vernalized medium sized (50-70g/bulb) mother
bulbs were selected and treated with Chlorpyrifos 400g/L EC (20ml/10Lof water) and Thiram
(80% (w/w) WP) (15g/10L of water).Treated bulbs were planted randomly in planting beds
according to the design. Watering was done daily. Oxyfluorfen 240g/L EC (11 ml/10 L of
water) was applied in 5 days after planting to control weeds and one or two hand weeding was
followed to effectively control the weeds. Recommended concentrations and volumes of
fertilizers and other chemicals were applied depending on the growth stages of onion. Hand
pollination was done 50 days after planting and it was continued for about 21 days. Matured
umbels were harvested in 85-95 days after planting and harvesting was continued for about 30
days. The umbels were air dried for about 15 days. Air dried umbels were sundried and
processed to separate seeds from seed heads. Cleaned seeds were dried to reduce the moisture to
8% and weighed.
Yield components of big onion plants were assessed during the study period. Number of umbels
per 1m , number of florets per umbel, percentage of fertile florets per umbel, number of seeds
per fertile floret, 1000 seed weight and total plot yield were measured as yield components.
Collected data of yield components were statistically analyzed using Analysis of variance
(ANOVA) in MINITAB 15 software.
Description
Keywords
Big Onion, Agriculture, Export Agriculture, Crop Production, Crop Production Technology, Vegetable Cultivation