Heterosis and combining ability studies in onion (Allium cepa L.)

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UAS, Dharwad
An investigation was taken to decipher the magnitude of diversity, heterosis and combining ability in onion. The material for the study consisted of 34 genotypes. These were collected from National Research Center on Onion and Garlic (NRCOG) Rajaguru nagar, IIHR Hesarghatta and local varieties maintained at Olericulture section, Department of Horticulture, UAS Dharwad were evaluated in randomized block design with three replications during 2004-05 to study the diversity, magnitude of heterosis and combining ability using Line X Tester analysis. Genetic diversity for yield and yield contributing traits was carried out involving 34 genotypes. Based on D2 value the total genotypes assigned in to 9 clusters indicating the presence of appreciable amount of diversity. The cluster III with two genotypes and cluster V with three genotypes were most divergent groups with maximum inter cluster distance (137.63). Out of 12 characters, bulb yield contributed maximum to the divergence The study on heterosis revealed that, significant heterosis was found for all the characters studied. For yield five hybrids exhibited significant positive heterosis over mid parent. Three crosses viz., NRCOG-937 x NRCOG-327, Bellary Red x NRCOG-327 and Telagi Red x Arka Kalyan have exhibited significant positive heterosis over better for yield. The Bellary Red proved as good general combiner for TSS and storage loss. For yield, Arka Pragati has found to be good general combiner for yield the crosses Telagi Red x Arka Kalyan and NRCOG-937 xNRCOG-327 were found specific combiners for bulb yield.