Resumo

SANCHEZ-HERNANDEZ, César et al. Heterosis in hybrids of squash type Grey Zucchini. Rev. Chapingo Ser.Hortic [online]. 2013, vol.19, n.1, pp.99-115. ISSN 2007-4034.  https://doi.org/10.5154/r.rchsh.2011.02.009.

The aim of the present study was to identify commercial hybrids with genetic value to produce high yield hybrids or varieties because commercial hybrids can be used with success in breeding programs. A total of eight commercial hybrids of squash (Cucurbita pepo L.) type Grey Zucchini and their 56 possible crosses were evaluated at Chapingo, Mexico during 2007 and 2008. Heterosis (average, varietal, specific) was estimated using the model II of Gardner and Eberhart (1966) and with respect to the best parent. Results showed positive average heterosis for all the characters (YH: 1.10 t·ha⁻¹; YPP: 13.10 g·plant⁻¹; FRW: 0.10 cm; FRL: 0.50 cm; DFF: 3 days and DMF: 3 days) studied. The hybrid 'Terminator' showed favorable positive effects of varietal heterosis for yield and components (RPH: 3.62 t·ha⁻¹; YPP: 63.37 g·plant⁻¹; FPP: 0.73 fruits, FRL: 0.33 CM, FRW: 0.20 CM, DFF: 1.66 days and DMF: 1.67 days). The best parents for yield were 'Terminator' and 'Lolita' because they showed greater varietal heterosis. The best crosses among hybrids were 'Grey Zucchini M+M' x 'Terminator' (3x7) (S_ij 3.78**), 'Hurakan' x 'Lolita' (5x4) (S_ij 3.86**) and 'Tala' x 'Terminator' (1x7) (S_ij 3.25**), which could be used in a breeding program to exploit the dominance effects by means of cyclic hybridization. The earliest three crosses, with 44 days to feminine flowering, were: 'Lolita' x 'Tala' (4x1), 'WA9041' x 'Tala' (6x1), 'Dolarzini' x 'Tala' (8x1) and the latest was 'Terminator' x 'Hurakan' (7X5)(54 days).

Palavras-chave : Cucurbita pepo L.; diallel analysis; fruit yield.

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