Seleção de genitores de trigo para estresse hídrico em fase inicial

Abstract

The use of wheat as an alternative in succession to irrigated rice. However, the cultivars available have little adaptability to the region, where they develop development problems due to the presence of floodplain soils. The stress caused by flooding negatively interferes with the physiology, growth and development of plants, thus limiting the productivity of the trichloric areas. The best understanding of the growth mechanism under conditions of oxygen deprivation can contribute to the proper management of the crops. Given the importance of culture in the market, the present work aims to estimate the genetic distance and to select parents for environments with water stress in the initial phase, through the selection of genetically distant parents, especially for the region, since it is a real and promising alternative . For this purpose, 26 wheat cultivars of different Brazilian breeders were used, in two treatments (with water stress and without stress) and four replications. The experiment was carried out in the laboratory at 20ºC during all the driving. The evaluations were carried out to determine the seedling temperature at 10 (T10) and 23 (T23) days after sowing (DAS), seedling length at 10 DAS, leaf length 1 and 2 (C.1ºF), (C.2ºF ) respectively, and, the production of green matter and dry matter. For analysis of variance, we used Scott and Knott at 5% probability, using the Genes computational program. Genotypes were classified by the generalized distance method of Mahalanobis. As a result, there was interaction of the variable length of 1st leaf (C.1ºF) with the treatment, being this along with the length of 2nd leaf (C.2ºF) the characters that contributed most to the analysis of the environment without stress. However, for the stress environment, several traits influenced the final choice of the cultivars, especially the length of the second leaf, followed by the length of the first leaf, dry matter, and green matter contributing as much as the temperature at 10 DAS (T10). The analysis of the obtained dendogram allowed to recommend genotypes to compose the crossing blocks. Thus, with the use of genetic distance estimation, it was possible to select parents for the environment without stress and water excess.