Correlation matrix on weed parameters, growth and yield attributes of onion (<i>Allium cepa </i>) under Sudan savanna agro-ecological zone of Nigeria

Controlling weed development during the onion crop cycle is essential to obtain high yields and marketable produce. Field experiments were conducted in a farmer ׳s field at Birnin Kebbi during the 2017/2018 and 2018/2019 dry seasons to assess the association between weed parameters, growth, and yield attributes of onion (Allium cepa L.) under Sudan Savanna agro-ecological zone of Nigeria. The experiment was made up of three planting populations (500,000, 333,333, and 250,000 plants per hectare) and twelve weed control methods (Pre-emergence application of pendimethalin at; (i) 1.0 kg a.i. ha-1, (ii) 1.5 kg a.i. ha-1 and (iii) 2.0 kg a.i. ha-1. Butachlor; (iv) 2.0 kg a.i. ha-1, (v) 2.8 kg a.i. ha-1 and (vi) 3.6 kg a.i. ha-1. Postemergence application of fluazifop-p-butyl, (vii) 2.0 kg a.i.ha-1, (viii) Oxyfluorfen at 1.0 kg a.i. ha-1, (ix) Weeding at 3 WAT, (x). Weeding at 3 and 6 WAT, (xi) Weed free, and (xii) Weedy check given 36 treatment combinations replicated three times and arranged in Randomized Complete Block Design (RCBD). Data collected were planted height, leaf area, weed control index, weed dry matter, weed control efficiency, crop vigor score, bulb diameter, fresh bulb weight, total bulb weight, marketable bulb yield, and cured bulb yield. Results showed that Fresh bulb yield, total bulb weight, bulb diameter and marketable yield correlated positively and highly significantly (p<0.01) with cured bulb weight. Correlations between any two parameters also showed that leaf area index and plant height, marketable bulb yield and bulb diameter were strongly and significantly correlated in both years. It is therefore recommended that fresh bulb weight, bulb diameter and marketable bulb yield should be used as higher yielding character for improving onion production in this agro-ecology of Nigeria.