Avaliação inicial de potenciais porta-enxertos de citros

Abstract

The diseases are one of the main problems for the citrus crop in Brazil, the fact that Rio Grande do Sul has its citriculture concentrated on a single rootstock ('Trifoliata') increases the phytosanitary risks, in a possible dissemination of diseases that this rootstock is susceptible. There is a great need to diversify the genetic basis of citrus rootstocks in the state of Rio Grande do Sul, which can be solved through studies of genotypes that adapt to the climatic conditions of the state. The goal of this study was to evaluate the development and adaptation of different rootstocks, from seed emergence to the period that preceds the grafting. The dissertation brings an article, elaborated in the years 2016 and 2017, at the headquarters of Embrapa Clima Temperado in Pelotas-RS . Entitled "Initial development of potential rootstocks for citrus", analyze the behavior of the rootstocks in the period in which the seeds are emerging, through the variables: seedling emergence percentage, iniciation, duration and emergency uniformity, as well as growth, through the variables of height and diameter measured from 130 days after sowing and adaptation to local climatic conditions by mortality rate. It was verified that Trifoliata rootstocks, TSKC X CTSW-041 and TSKC X CTSW-025, showed seeds with higher seedling emergence, and that 'Trifoliata' showed premature emergence, faster and more uniform compared to the others. It was possible to observe that many rootstocks did not develop well under local climatic conditions, such as the LCR X CTSW-009 and LVK X LCR-039 genotypes, which had 100% and 90% of dead plants respectively. On the other hand, it was verified that some genotypes were perfectly adapted, the 'Swingle' citrus tree rootstock, presented higher height and diameter associated with a very low mortality, other rootstocks besides the 'Swingle' citrus tree are promising for citrus cultivation of the state due to superior initial development and low mortality, such as the genotypes Cleo X TRBN - 245, Cleo X TRSW - 287, citrandarins 'Índio', 'San Diego' and 'Riverside', LRF X (LCR X TR) - 005 and lemon tree 'Cravo'.