Development and Gas Exchange of Pre-sprouted Sugarcane Seedlings in Three Different Growing Substrate Media

Abstract

Objective: Evaluate the development and gas exchange of pre-sprouted sugarcane seedlings in different substrates. Study Design: A randomized complete block design was used with two genotypes, three types of substrate (2 x 3), four replicates and five plants per replicate, totaling 120 plants. Location and Duration of Study: Department of Crop Sciences of the Center for Agrarian Sciences, Universidade Federal de Paraíba in the city of Areia, Brazil, between August and October 2018. Methods: The following were the treatments: T1 – genotype 1 in commercial substrate; T2 – genotype 1 in commercial substrate + bovine manure; T3 – genotype 1 in bovine manure + sand; T4 – genotype 2 in commercial substrate; T5 – genotype 2 in commercial substrate + bovine manure; T6 – genotype 2 in bovine manure + sand. Variables analyzed: height, diameter, dry mass of shoot and root and physiological response of seedlings. Results: A significant difference at the 1% level was found for the dry matter of the seedling roots among treatments with difference substrates. A significant difference at the 1% level was also found for shoot length and a significant interaction at the 5% level was found between genotype and substrate for this characteristic. Significant effects were found with regard to the rate of photosynthesis, stomatal conductance, transpiration and carboxylation efficiency. Conclusion: The substrate with manure + sand favored the accumulation of root dry matter and shoot length. Genotype 1 exhibited its best performance with regard to photosynthesis and stomatal conduction in the treatment with the commercial substrate and demonstrated greater carboxylation efficiency than genotype 2, independently of the substrates. The pre-sprouted seedling production system needs to be explored further to obtain greater information regarding the nutritional requirements and characteristics of the genotypes.