Regimes hídricos no desenvolvimento de acessos do gênero Manihot

Abstract

ABSTRACT The objective of this work was to select water deficittolerant accessions of the genus Manihot, through morphological characters under different water regimes. The experiment was conducted in a randomized block design, using a split-plot arrangement with plots consisting of tree water regimes (simulated rainfall and water depth of 100 and 20% crop evapotranspiration (ETc)), and subplots consisting of eight accessions of the genus Manihot (Gema-de-Ovo and Engana-Ladrão from the species M. esculenta Crantz, and BGMS-115, BGMS-110, BGMS-102, BGMS- 79, BGMS-24, and BGMS-48 from Manihot sp.). The accessions were evaluated considering two crop cycles: the first had 120 and 60 days from the application of the treatments. Plant height, stem diameter, number of leaves, leaf lobe length and shoot dry mass production were evaluated. For each cropping cycle, a split-plot analysis of variance was performed. The highest genotypic means were expressed by the accessions BGMS-115, BGMS-102, BGMS- 79 and BGMS-24 for most of the analyzed variables, regardless of the cultivation cycle. For the characteristic shoot dry mass production, accessions BGMS-102 and BGMS-79 showed the best performances under conditions of limited water regime (20% ETc), regardless of the cropping cycle. Accession BGMS-102 was also grouped in the group with the highest genotypic means, for this trait, in treatments with rain simulation and 100% ETc, in the first cycle, demonstrating that, under stress conditions, this accession is an option to tolerate low water precipitation and responds well when higher precipitation occurs.