Genetic parameters, dissimilarity and performance of pumpkin accessionsPumpkin is very important in human and animal food, especially concerning family farms. The germplasm bank of vegetables of Universidade Federal de Viçosa (Federal University of Viçosa, UFV-BGH), Brazil, has several pumpkin accessions with wide genetic variability. All this genetic variability is of great importance for plant breeding. However, little is known about the true potential of BGH-UFV, because there are few scientific papers published with information on these accessions. The objective was to obtain information on genetic parameters, dissimilarity and performance of BGH-UFV pumpkin accessions. We evaluated 11 morphological descriptors of 55 accessions and three cultivars. The genetic parameters, expected gain with selection, phenotypic, genotypic and environmental correlations were estimated. For the dissimilarity study, the Tocher test was carried out and graphic dispersion of the canonical variables was evaluated. There was genetic variability among accessions, with a predominance of genetic effects over the environment. Higher gain selection for mass per fruit, plant appearance and location of the first male flower node are expected. The commercial cultivars Butternut and Tetsukabuto have excelled due to the lower mass per fruit and precocity of flowering, but they had the worst results in terms of phytosanitary aspect. There are negative correlation estimates between the phytosanitary aspect and growth habit, length and growth rate of the main stem, indicating that compact plants may have greater phytossanitary problems. Crossing accession BGH-7003 or cultivar Butternut with accessions BGH-1946 or BGH-7765 can generate progenies with potential for breeding.

RESUMO: Avaliou-se desenvolvimento de mudas de melancia em substrato comercial com diferentes doses de hidrorretentor. O experimento foi desenvolvido na Universidade do Estado da Bahia, Juazeiro-BA. Sendo o delineamento inteiramente casualizado, com cinco tratamentos e três repetições. A semeadura foi realizada em bandejas com 162 células, com três doses do polímero hidrorretentor (T1-1 g kg-1 , T2-2 g kg-1 e T3-3 g kg-1 de substrato) e duas testemunhas (T4 e T5) sem polímero hidrorretentor. Os tratamentos de T1 a T4 foram irrigados uma vez ao dia com 5 mL de água. O T5 foi irrigado duas vezes ao dia com 5 mL. Utilizou-se a cultivar de melancia Crimson Sweet. Ao final de 13 dias após a semeadura avaliou-se: emergência (E), índice de velocidade de emergência (IVE), altura da plântula (AP), diâmetro do hipocótilo (DH), comprimento e largura dos cotilédones (CC e LC), massa fresca da parte aérea (MFPA) e massa seca da parte aérea (MSPA). Obteve-se diferenças estatísticas para as variáveis IVE, AP, CF e MFA. O uso do hidrorretentor não afetou E, CC, LC, DH e CF. O T4 foi superior a T5 para AP e CF. A utilização da dose mínima do polímero resultou na produção de mudas de qualidade com 50% de economia de água.

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