Stalk dry mass and industrial yield of 16 varieties of sugar cane cultivated under water restriction

The great extension of the cultivated area, associated with the low water availability to supply the sugarcane demand in the periods of drought and the high evapotranspiration demand, requires varieties adapted to these specific conditions. The aim of this study was to assess 16 sugarcane varieties regarding the efficiency in water use (EWU) and in photosynthetically active radiation (PAR), cultivated under a water restriction, in the production of stalks dry matter, sugar and alcohol. The experiment was carried out in the Brazilian savannah biome, Goiás State, during the 2011/2012 crop year, in a randomized blocks design, with four repetitions. The treatments consisted of 16 varieties of sugarcane cultivated on a supply of only 50% of the water demand demanded by the crop. The EWU and EUPAR of the varieties were evaluated for the production of stalk dry mass (SDM), sugar and alcohol. During the crop cycle there was sufficient precipitation to supply the water demand of sugarcane; however, the irregular distribution of rainfall resulted in a water deficit of -697 mm during its cycle. The varieties IAC 91-1099, CTC-15, CTC-11, SP 86-0042 and IAC 87-3396 showed higher EWU and better photosynthetically active radiation for the production of stalks dry matter, sugar and alcohol. IACSP 94-2094 and CTC 09 varieties presented the same efficiency in industrial yield and lower dry matter yield than the five following varieties IAC 91-1099, CTC-15, CTC-11, SP 86-0042 and IAC 87-3396. Therefore, these last varieties are the most efficient in water use and photosynthetically active radiation aiming the stalks dry matter, sugar and alcohol production under water restriction.