Indicadores resposta à deficiência hídrica em cana-de-açúcar

Abstract

Water restriction is highlighted as a problem that affects a large proportion of areas cultivated in the world, especially those located in semi-arid regions. This work aimed to identify the response of varieties of sugar cane to water deficit evaluating gas exchange and growth in two consecutive cycles during the vegetative phase of its development. Thus, the plants were grown on the field at the State University of Montes Claros - campus Janaúba-MG. We used three varieties of sugar cane (SP70-1011, SP80-1842 and RB86-7515) under two water regimes: 80-100% of field capacity and water restriction from 40to 60% of the field capacity. Plant response was analyzed from the following variables: SPAD index, plant height, number of tillers, plant diameter and gas exchange (photosynthesis, transpiration and stomatal conductance), percentage of leaf water, chlorophyll fluorescence. Physiological indicators were more sensitive to variation of soil water moisture. The water deficit in 2013 was less severe than in 2012 not being able to cause stress in plants. TheRB86-7515 variety showed lower sensitivity to water deficit for most of the parameters studied and the SP80-1842 variety showed the thighest one. The used responses indicators were effective to show the behavior of sugar cane as for water deficit.