Heterosis and Combining Ability Studies in Onion (Allium cepa L.)
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Date
2016-09
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University of Agricultural Science, Dharwad
Abstract
An investigation was conducted in the Department of Horticulture, College of Agriculture, Dharwad to study the heterosis and combining ability studies in onion (Allium cepa L.) with the objectives of identifying good general combiners and to assess the magnitude of heterosis for seventeen characters and to know the performance of hybrids. In the present investigation 54 entries have been evaluated (13 parents : 40 hybrids : 1 commercial check). Performance of hybrids like GKD-75 x Line-13 (11.83 t/ha), Kumata local x Line-13 (10.57 t/ha), ASKO-1201 x Cross-5 (9.60 t/ha) and Kumata local x cross-5 (8.88 t/ha) for the marketable yield was better than commercial check – Bhima Shakti (6.55 t/ha). These expressed considerable magnitude of heterosis over commercial check for yield. The top yielding entries [GKD-75 x Line-13 (4.013), ASKO-1201 x Cross-5 (2.431) and Kumata local x Line-13 (2.258)] involved positive (significant) x positive (significant) general combiner. Variance due to GCA and SCA was significant for the yield trait, indicating the involvement of both additive and non additive gene action. However, the estimates of SCA were higher than GCA variances indicating predominance of non-additive gene action in controlling the inheritance of this trait during kharif season.
Marketable yield is the ultimate and most important trait. The performance of hybrids for marketable yield point to entries like ASKO-1299 x GKD-77 (26.80 t/ha), ASKO-1201 x Line-13 (26.25 t/ha), Bhima Shakti x Line-13 (26.25 t/ha), ASKO-1201 x GKD-77 (26.20 t/ha) and Bhima Shakti x cross-5 (24.65 t/ha) are statistically at par with commercial check [Bhima Shakti (24.6 t/ha)]. Expressed considerable magnitude of heterosis over commercial check for yield. For marketable yield, significant positive SCA effect for this trait was exhibited by cross ASKO-1299 x GKD-77 (5.602) which involved positive (non significant) x positive (significant) general combiner. This was followed by Bhima Shakti x Line-13 (5.207) which involved negative (significant) x positive (significant) general combiner. Variance due to SCA was significant indicating the involvement of non additive gene action during rabi season.