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Heterosis of purple blotch (Alternaria porri (Ellis) Cif.) resistance, yield and earliness in tropical onions (Allium cepa L.)

Author:
Abubakar, Lawali, Ado, Shehu G.
Source:
Euphytica 2008 v.164 no.1 pp. 63-74
ISSN:
0014-2336
Subject:
Allium cepa, onions, cultivars, varieties, disease resistance, fungal diseases of plants, Alternaria porri, heterosis, crossing, plant development, maturity stage, leaf development, crop yield, early development, bulbs, agronomic traits, Nigeria
Abstract:
Five open pollinated onion cultivars Red Creole, Kaharda, Koumassa, Sokoto local and Ori were crossed in a complete diallel and their progenies were evaluated in replicated trials, at Sokoto and Talata Mafara, Nigeria, during the 2004/2005 and 2005/2006 seasons. The experiments were randomised as complete block design with three replications. 30 mls of 10⁻¹ cfu of spore suspension of Alternaria porri prepared by serial dilution was poured into the centre of each plot (sunken bed) immediately after irrigation at 2 weeks after transplanting. Combined analysis across seasons and locations indicated significant (P < 0.05) differences between the populations with respect to all the characters under study. Crosses Ori x Koumassa and Koumassa x Ori recorded highly significant (P < 0.01) positive high parent heterosis for bulb diameter. Crosses Ori x Sokoto local and Ori x Koumassa recorded highly significant (P < 0.01) negative high parent heterosis for days to maturity. Cross Sokoto local x Koumassa exhibited highly significant (P < 0.01) positive high parent heterosis for number of leaves/plant. Crosses Red Creole x Kaharda and Kaharda x Red Creeole recorded highly significant (P < 0.01) positive high parent heterosis for disease incidence. Red Creole x Kaharda and Kaharda x Red Creeole also recorded highly significant (P < 0.01) positive high parent heterosis for fresh bulb yield. Cross Kaharda x Ori recorded highly significant (P < 0.01) positive high parent heterosis for bulb weight. The cross Kaharda x Sokoto local recorded significant (P < 0.05) negative high parent heterosis for days to maturity while the cross Red Creole x Kaharda recorded highly significant (P < 0.01) positive high parent heterosis for number of leaves/plant. Bulb diameter and bulb weight recorded highly significant (P < 0.01) and significant (P < 0.05) environmental correlation with days to maturity.
Agid:
739254