EFFECT OF INTRA-ROW SPACING ON GROWTH PERFORMANCE AND YIELD OF ONION (Allium cepa L.) VARIETIES AT MIZAN-AMAN, SOUTHWESTERN ETHIOPIA

Abstract

Onion is among the most important vegetable crops produced in Mizan-Aman for home consumption and as income sources. However, lack of site based varieties and inappropriate planting density have been the major bottlenecks of onion production and productivity in the area, since there are no recommended spacing and variety for that area specifically. Rather farmers use to practice non-uniform plant spacing. This study was thus conducted at Mizan ATVET College in 2015/2016 with the objective of investigating the effect of intra-row spacing on growth performance and yield components of onion varieties. Three varieties (Adama Red, Bombay Red and Melkam) were evaluated under four different intra-row spacings (6, 10, 14 and 18 cm) and constant inter-row spacing of 20 cm by using randomized complete block design replicated three times. Data on days to maturity, growth performance and yield were recorded and subjected to analysis of variance using SAS version-9 software. Results of the study indicated that, intra-row spacing and variety had significant effect on plant height, leaf number per plant, leaf length, days to maturity, bulb diameter and length, bulb dry matter, total bulb yield as well as, marketable and unmarketable bulb yield. Closer intra-row spacings enhanced early maturity, while wider spacing delayed maturity. The maximum plant height, leaf length and leaf number were recorded in 10 cm intra-row spacing. Bombay Red variety was early maturing with the highest mean value for growth and yield parameters. It had the highest total bulb and marketable bulb yield than Melkam and Adama Red onion varieties specially when planted at 10 cm intra-row spacing. Bombay Red with 10 cm intra-row spacing also gave highest total bulb and marketable bulb yield. The correlation values also confirmed the significant and positive association between growth parameters and bulb yield. Based on the result of this study, higher onion yield with better quality was attained when Bombay Red variety was planted with 10 cm intra-row spacing under Mizan-Aman condition, for recommendation, although additional verification trial is needed to substantiate the result.